Gadgeteer Genius



"He said: "To hell with moisture detectors. I'm going to build a giant robot." So we built a giant robot."

- Everything2 Podcast

It doesn't matter if she's 13 years old or 13,000, she's the greatest scientific genius in the universe and can prove it by building a 50,000-horsepower battle robot out of tin cans and an old transistor radio. Overnight. Sometimes her creations fail with entertaining explosions, but they always work for at least a little while. In Anime, the Gadgeteer Genius is usually female, and often still in grade school. In Western depictions the gadgeteer is usually male, and can be of any age.

There can be a very fine line between Gadgeteer Genius and Mad Scientist.

A Wrench Wench is a slightly more realistic depiction. Expect her Battle Cry to be "For Science!"

When the Gadgeteer Genius's creations cannot be replicated by lesser minds see The Spark of Genius. When it's the results are impossible according to internal logic and Played for Laughs, it's Impossible Genius.

When the character is known for skill in electronics rather then mechanics he or she is a Techno Wizard. It is possible of course for the same character to be both or for a Gadgeteer and a Techno character to compliment each other on the same team.

Anime and Manga

 * Bulma will single-handly perfect time-travel, launch the space exploration industry, and artificially produce energy comparable to a small celestial body if it will help Goku or Vegeta. Gotta love that girl.
 * Washuu from Tenchi Muyo! In the original OVA she actually isn't much of a gadgeteer—most of her time was spent in doing research so complex that the viewers were rarely let in what she was doing. The later TV series increased her gadget-building role considerably.
 * Rin-Rin from Sister Princess can build custom laptop computers overnight for pocket change, complete with her own hand-written operating system. She's also built an android duplicate of herself, but the poor thing can't speak and is still a bit klutzy at household chores.
 * Li Kohran from Sakura Taisen.
 * Skuld from Ah! My Goddess: when she came into contact with an actual professor of robotics, he almost went mad at the sight of a little girl who could make functional battle robots when he was struggling to make a robot that could walk. Of course she is the goddess of the Future, so it's slightly excusable.
 * Kaolla Suu from Love Hina.
 * Nanoca Flanka from Aoi Umi No Tristia (Tristia of the Deep Blue Sea).
 * Rika Domeki from Dai-Guard.
 * Satomi Hakase in Mahou Sensei Negima.
 * Not to mention Chao Lingshen.
 * Hayashida Heihachi in Samurai 7.
 * Niea from NieA 7 was shown to have built a functional UFO out of trash materials, and powered by a regular AC power outlet. Unfortunately, it exploded once it was unplugged.
 * Irina Woods, one of Arika's friends and roommates from Mai-Otome, has taken a great interest in engineering. She even tried to build a giant house-cleaning machine to assist Arika with her punishment duty (which broke down almost immediately, but at least she tried).
 * Nina Einstein from Code Geass. She invented a in the last episode of the first season using the contents of a High School science lab! Granted, it was only semi-functional and broke down before, but STILL. And not to mention, she later did build a functioning ... with disastrous results.
 * And by the end of S2... she builds an device. In a month. And it works, both for Lelouch and her fandom reputation (partially, in the latter's case).
 * Sonic X: Chis Thorndyke's aged up and smarted up version pretty much fills this role.
 * Tails is a better example.
 * Shari of Magical Girl Lyrical Nanoha, who by the age of 17, had already created the Danger Room-like training grounds of Riot Force 6 and the Intelligent Devices of the rookies.
 * Chie from Hyakko is still in high school, but is quickly advancing in the field of robotics. Her most notable achievement to date is Mecha-Torako.
 * Dr. Agasa from Detective Conan.
 * Toma is training to be a magical version of this in Doki Doki Densetsu Mahoujin Guru Guru
 * Rat from Free Collars Kingdom.
 * Spanner and the future Giannini from Katekyo Hitman Reborn. They can do anything. Including building giant robots and motorcycles which are as quiet as mimes.
 * Notably, both are male.
 * Franky and Usopp of One Piece. Franky is much more advanced, able to build crazy machines and ship-enhancements, while Usopp has that original flavor, his best example being Nami's weapon, the Clima Tact.
 * B-Ko from the Project A-ko series, who introduces a Humongous Mecha, complete with heat-seeking missiles, laser weaponry and titanium armor, with the nonchalant disclaimer that "it did take me most of last night to build". She's not bluffing, either: until she eventually settles into a Powered Armor suit, she spends about a week going through more and more elaborate new mechas on a daily basis.
 * Hotaru of Gakuen Alice. Her's is the invention Alice.
 * Ursula Hartmann from Strike Witches combines this with Improbable Age. A 10-years old who is a rocketry expert.
 * So does Noel from So Ra No Wo To,.
 * Kana/Kanna from NEEDLESS have this as her superpower.
 * Hanaukyo Maid Tai. Ikuyo Suzuki, head maid of the Technology department. Among her inventions are a Weather Control Machine, an amphibious giant robot in the shape of a brontosaurus and a vehicle capable of Teleportation.
 * For a Jidai Geki series, Ayakashi Ayashi has one hell of an example - Masurao, a member of the 'People of the Craft', proves capable of whipping up devices in feudal japan that would be considered revolutionary TODAY - including a fully-functional handgun made from paper. His Crowning Moment of Awesome, however, comes when he is pursued by the heroes through a construction-site, grabs some random pieces of wood and some tools without slowing, and craft them into an attack-robot to sic on his pursuers. Without ever stopping.
 * The Child Prodigy in the Kuroshitsuji manga goes in a space of a few weeks from not knowing anything about technology to single-handedly inventing the field of robotics... in 1889.

Comics

 * X-Men's Forge has the ability to intuitively determine how anything works, and by this point, after years of exposure to all manner of gadgetry, is able to whip up any manner of Applied Phlebotinum you can possibly imagine. We're talking Star Wars level.
 * He is also a shaman. This fact isn't brought up so much, because combining the two aptitudes leads to questions of why he has not whooped most of evil's ass by now.
 * Oh, but he has. He stopped the Adversary, an evil Physical God and banished it from the world. Twice. It's probably going to.
 * Scalphunter, a member of the Marauders that regularly clash with the X-Men has these technical abilities too, being able to reform mechanical components into anything he can think of. Given that he's a murderous Psycho for Hire, he generally tends to create shotguns, grenade launchers, high-powered automatic rifles, and other lovely toys.
 * The writers of X-Men: Evolution decided that wasn't Badass enough and gave him the ability to transform his arms into any imaginable tool to help him make his creations. Considering the tendency of his creations to get away from him, one must wonder if he's not as good as his comic and 1990s series counterpart or if he's simply a lot less responsible.
 * Angie from the superhero comic PS238 by Aaron Williams (author of Nodwick) combines the ability to make just about anything out of old cars and other junk with having the mindset of the cast of Pimp My Ride. Bling-bling and Explosive Overclocking tends to riddle whatever she ends up building, which is just the way she likes it.
 * And of the male (and not quite as explosive) type, the school also hosts Zodon and Herschel Clay, who both have significant gadget construction and tinkering skills in addition to (or due to) being prime examples of, respectively, the Evil Genius and the Mr. Fixit.
 * Brainiac 5. He's been described as a genius among a species of geniuses, the type of prodigy that comes along once in a millennium (which is how far the Legion is from the rest of the DCU). The solution and cause of a lot of the Legion's problems. Is currently working on rebuilding the economy of the United Planets and inventing a new way to break the speed of light.
 * Iron Man, who in turn inspired a Gadgeteer Genius (aptly codenamed Gadget) to build a tech-suit in her garage. Probably from a box of scraps.
 * In Astro City, Beautie's origin is revealed:
 * Not to mention the Junkman, who uses stuff that's been thrown out to create his devices (as he considers himself cast off by society because of his age). Despite the self-imposed handicap, he is one of the few villains in Astro City who, as it is implied he with the recognition he craved and all the loot he stole.
 * Alpha Flight supporting cast member Madison Jeffries has the mutant power to physically alter machines, metals and related inorganic objects, which he initially used as a mechanic. (His brother Lionel had a similar power over living tissue, which had gruesome results when he went insane. Another more conventional genius was Box, a quadriplegic who used his tremendous scientific skills to build machines that overcame his disability.
 * The original, pre-Crisis version of Lex Luthor was the archetype of all comic book Mad Scientists, but he most displayed his juryrigging skills with his trademark jailbreaks. For instance, a substitute prison warden was dumb enough to get him to fix a printing press and he turned it into a tank like escape vehicle to smash his way out. Sometimes he would smuggle tools inside with him when he was carted off to jail—tiny tools hidden under a false patch of skin on his thumb for example—but he was perfectly capable of building an escape device without them.
 * In Warren Ellis's newuniversal (based on The New Universe), this is the power provided by the Cipher Power Tattoo. Of the three known bearers, one was a prehistoric woman who invented electric lighting and energy weapons, but believed they were gifts from the gods; one was this world's version of Tony Stark; and the most recent is Humongous Mecha designer Dr Jennifer Swan.
 * Too many Marvel Comics characters to list, really. Reed Richards, Bruce Banner, Henry Pym, Tony Stark, and the Black Panther are some of the most prominent heroes, while Doctor Doom, the Wizard, the Terrible Tinkerer, the Mad Thinker, and the Fixer are prominent villains.
 * There's also Tom Thumb and Master Menace from Marvel's Squadron Supreme alternate universe.
 * Gyro Gearloose can build literally anything. In one story he built a functional space rocket out of a couple of toasters and duct tape, overnight.
 * Lewis, Mechanika's armourer in Lady Mechanika.
 * Al Jabr in Demon Knights. It's The Dark Ages and he has a telescope and an electrified whip.
 * Batman is this to a certain degree. Though most of his larger contraptions (like a Satellite that monitors all meta human activity down to the slightest) are built by a subsidiary of his corporation, WayneTech, making this overlap with Crimefighting with Cash. That being said, most of his arsenal (including the Batsuit) is designed and built by himself.
 * Fantasio of Spirou and Fantasio was a talented inventor in the earlier volumes. Later volumes ignored this attribute but his skills are alluded to in "Aventure en Australie", where he fixes a broken down train despite everyone in town insisting that it was beyond repair.
 * Most recently Static in the pages of Teen Titans. Previously, Static was just a very bright kid, but in Lobdell's Teen Titans, he's become a full blown Teen Genius: designing Red Robin's glider wings and creating a new costume from scratch for Kid Flash that prevents his powers from vibrating him to nothing.
 * Ted Kord as the Blue Beetle is the defining example of a gadgeteer genius superhero. He invented all of his gear himself, a lot of which was reverse-engineered alien technology (you think HTML code is tough?), up to and including a beetle shaped flying ship. Guy Gardener has even said that Ted was smarter than Batman.

Fan Works

 * Calvin is exaggerated into this in Calvin and Hobbes: The Series. Among his inventions include the MTM, Mega Shrinker 5000, Time Stopper, Movie Transporter...

Films

 * Doc Brown, slightly crazy inventor and engineering genius from the three Back to The Future movies. Built a time machine in the form of a Delorean car. Then a second even more stylish time machine which combined a 19th century steam locomotive with antigravity and cold fusion technology from the future.
 * He turned a regular steam train into a time traveling steam train with nothing that didn't exist before the 1800s, except for a hover-board.
 * And let us not forget his epically-impractical ice-making machine.
 * The Blade movies (especially Blade Trinity) have several characters who build high-tech equipment for the vampire hunters. Seriously... ultraviolet light bullets??
 * Q from James Bond, although he's the chief of a MI 6 sector of Gadgeteer Geniuses.
 * In several of the novels by John Gardner, Q/Major Boothroyd's character is downplayed so Bond can flirt with his Hot Scientist assistant, Ann Reilly. Her nickname is "Q'ute," which explains a lot.
 * Tony Stark in the 2008 Iron Man movie (not to mention the comics it's based on) is depicted as a gadgeteer genius. He builds the power suit prototype and his own Unobtainium artificial heart using spare parts provided for the construction of a Jericho missile. In his own lab, he creates even more impressive gadgets.
 * Both Artemus Gordon and Dr. Loveless fill this part in Wild Wild West. Artie creates the first bulletproof vest and a primitive airplane; the Dr. Loveless produces an enormous mechanical arachnid.
 * To be fair, most of the work for the latter is done by the scientists he has captured. He doesn't even hide that fact. He's smart enough to survive being blown in half.
 * Lewis from Meet the Robinsons.
 * Willy Wonka is a Candy Genius, which wouldn't normally qualify. However, considering he built not only the Factory but the Great Glass Elevator, one suspects his skills go a bit beyond chocolate.
 * Yes, but he also had an army of Oompa-loompas - some of which may have actually come up with the designs themselves.
 * Dr. Cockroach from Monsters Versus Aliens managed to build a working computer out of a pizza box and paper clip, and that's after an experiment turned him into a humanoid cockroach. If he ever gets his hand on a box of LEGO bricks and some uranium, watch out!
 * Gwen/Royal Pain from the super-teens comedy Sky High calls herself a "technopath." She demonstrates the ability to magically repair electronics, as well as presumably designing and building her own armored super-suit.
 * Anakin Skywalker of Star Wars fame built a protocol droid and a pod racer before the age of ten.
 * The Specials: Mr. Smart, smartest man in the world, inventor of such devices as a winged rocket-backpack and a machine that amplifies his sense of smell 3,000 times.
 * Flint Lockwood from Cloudy with a Chance of Meatballs.
 * Ling Ling Fat (008) in Steven Chow's Forbidden City Cop is a genius inventor who uses his wits to protect the Emperor better than the kung-fu masters making up the rest of the Imperial Guard.
 * The title character of The Adventures of Buckaroo Banzai Across the 8th Dimension invented the Jet Car, a surgical technique to implant a microphone in the human skull so people can give orders to their own brain, and (with Professor Hikita) the Oscillation Overthruster. And that's just what was mentioned in the movie - it's implied that he's done much more.

Literature

 * Tinker in Wen Spencer's Tinker novels.
 * In the Discworld novels by Terry Pratchett, a recurring character is the befuddled genius inventor Leonard of Quirm (an obvious parody of real-world Renaissance Italian inventor and painter Leonardo da Vinci).
 * In Thief of Time, we encounter the gadgeteer Qu, an obvious parody of James Bond's Q.
 * The Wild Cards series features quite a few gadgeteer characters, such as Jetman, but in a subversion, the gadgets they make don't actually work. Some of them actually have no means of operating. The gadgets are just tokens that serve as a crutch for their powers.
 * Foaly from Artemis Fowl. He is stated to be the reason the People are still ahead of humans.
 * Ashley Stalworth from Dragons in Our Midst.
 * Tom Swift is the ur-example, making this trope Older Than Radio.
 * But don't forget Frank Reade Jr. or Johnny Brainerd.
 * Soledad O'Rourke of Those Who Walk In Darkness is a specialist, only designing Abnormal Ammo. However, she deserves to be on this list after creating BLAM bullets, which "lock in on molecular structures in a state of hyperkinetic motion," turning in midair to target foes who possess Super Speed.
 * Tom Clancy's Net Force, based on the name alone, would be expected to have a lot of these. And it does. But no one can best Jay Gridley.
 * One guy bests Jay Gridley, but it takes a Quantum Computer (manifested as a T-Rex) to do so. Gridley eventually recovers, hunts it down in VR, and blows it away with a rocket launcher.
 * In the novelization of Metropolis, Rotwang is one of these mixed with Mad Scientist Classic. He was Joh Fredersen's right-hand man in building the titular city, and in only a few years designed all its major technical achievements: the workers' underground city, all the machines, the reservoir, the subway, the road system, and the New Tower of Babel. (Even the soundproofing in Fredersen's office is named for him.) Even in his stagnant period following the loss of his wife Hel, he builds a mechanical replacement arm and a robot companion. Fredersen esentially imprisons him in the city to act as emergency technical advisor.
 * Brother Kornhoer from the second section of A Canticle for Leibowitz creates a working electrical generator and an arc lamp with wagon wheels, melted coinage, a bit of graphite, and some newly-recovered theoretical knowledge. The Isaac Newton-expy is floored to see it.
 * In the Percy Jackson and The Olympians series (and the sequel series, The Heroes of Olympus), all of Hephaestus' demigod children are this. Their cabin is MUCH bigger on the inside due to very clever (and probably impossible) design.
 * Abner Perry in At The Earth's Core by Edgar Rice Burroughs.
 * Violet Baudelaire in A Series of Unfortunate Events. This girl used a window shade and six roller skates to make an automatic rolling pin. When she was five.
 * Cogs in The Grimnoir Chronicles books are exactly this. Unlike most other examples though, Cogs tend to be specialized.
 * The main character of The Chronicles of Professor Jack Baling is able to build a disintegrator gun out of parts from his microwave, flatscreen TV, laser pointer, refrigerator, and his wife’s hair dryer that plugs into any standard wall socket.
 * Isaac Asimov's short story "Homo Sol" portrays Earthpeople as, by comparison with the Galaxy's other intelligent peoples, an entire species of these — specializing in weapons. One extraterrestrial describes how Earth's researchers rebuilt an alien geological sensor, used to detect ore deposits and not very effective, as an absolutely deadly targeting sensor: "It will automatically lay a gun or projector on a completely invisible target in space, air, water — or rock, for that matter."

Live Action TV

 * One of the most famous gadgeteers of TV was MacGyver, although he was more of a tinkerer. The series that spawned the term "MacGyvering." Usually worked alone, without a sidekick. Oddly enough, though, there was an episode of MacGyver where he teamed up with a classic Gadgeteer Genius girl—an ultra-intelligent schoolgirl who could match him move-for-move.
 * Micah from Heroes is a ten-year-old boy whose mastery of machines allowed him to make his own circuitry for his computer. This is later explained to be of machines.
 * Magical Version: in Charmed, The Scrappy Billie managed to "MacGyver up" a magical potion from the contents of a hostage's purse, despite the show always stating that potion ingredients are quite specific.
 * Basically every Chief Engineer from Star Trek is an engineering genius: Scotty, Geordi La Forge, Miles O'Brien, B'Elanna Torres, "Trip" Tucker.
 * Starfleet Engineers in general seem to have a reputation for this. In the Deep Space Nine episode "Rocks and Shoals," a wounded Vorta says of a broken transmitter system, "It needs repair, but I'm willing to bet that you've brought one of those famed Starfleet engineers who can turn rocks into replicators." Further, in the Expanded Universe there's an entire novel series called "Starfleet Corps of Engineers."
 * Presumably, the dry dock engineers are geniuses too, since they manage to survive and repair all the alien tech that all homecoming vessels seem to be infested with.
 * Spock was also sometimes expected to be a Gadgeteer Genius, even with only primitive materials to work with. In "City on the Edge of Forever," he expresses his frustration at having to do this with 1930's technology: "I am endeavoring, ma'am, to create a mnemonic memory circuit, using stone knives... and bearskins."
 * On the original series, while Scotty did an impressive job MacGyvering and was a remakably fast and thorough Mr. Fixit, plot-resolving new technology usually required a teamup with Spock, who was otherwise fairly consistently presented as a theoretician and IT man.
 * Justified with the Enterprises because, as capital ships, their officers are the best of the best from an organisation spanning hundreds of planets, or in the case of Enterprise, at least the whole of Earth.
 * For Deep Space Nine, Miles O'Brien was actually Chief Petty Officer on a Federation outpost, and they don't hand those positions out readily. For Voyager, well, Maquis, being outlaws with secondhand gear, have to do a lot of MacGyvering, and apparently Torres was just the best at it.
 * Lampshaded in the 2009 movie: Scotty is just a little too smart for his own good, having beamed "Admiral Archer's prize beagle" across the galaxy for a bet. To allow him time to wait for it to arrive, he's sent to the Starfleet equivalent of a remote Alaskan radar station. Apparently, Porthos was going to re-materialize at the very end of the film, but it was cut for time, alas.
 * Seamus Zelazny Harper from the spaceship Andromeda is both an engineering genius (which by later seasons extends itself even to human cloning) and also a hyperactive archetypal Mr. Fixit and tinkerer.
 * Power Rangers has had several characters who could apparently create/repair Humongous Mecha in a matter of hours. The most egregious example is the Ass Pull of two fully-functional copies of a mecha introduced out of the blue. Cam's just that good.
 * Then there's the fact that Billy Cranston, the first Blue Ranger, invented a collection of wristwatches that could be used both as personal communicators, and could remotely activate an alien teleportation grid. Villains aren't the only ones who could Cut Lex Luthor a Check.
 * The most impressive part? He put the teleportation thing in by accident. He was just trying to connect to the alien communications network. The day after meeting the aliens for the first time.
 * Supposedly, the Professor from Gilligan's Island, though just how good he is remains something of a mystery as he can't patch a hole in a boat.
 * Maritime engineering clearly just isn't his thing.
 * Can't, or won't? Plenty of folks believe he just played dumb with fixing the boat, knowing that he'd never get a better shot at Ginger and Maryanne once they got back to civilization.
 * In Doctor Who, the Doctor can save the universe with a kettle and some string, though he usually does so off-camera. He also has a knack for taking diabolical inventions cobbled up for some nefarious purpose and subverting their intended purpose, usually with disastrous results for the villain of the day.
 * Also Professor Yana,, who build a rocket's computer system "out of food and string and staples."
 * Pixel and Robbie Rotten from LazyTown.
 * Pixel is able to build almost anything, from hovering cameras, to a device that can transport people into storybooks, to a remote control which can control literally everything, including random electronic things he has in his room to people. In Secret Agent Zero, the 007 parody Episode, he played the role of Q. And he is 9 years old.
 * Robbie Rotten can build anything out of anything he has in his lair. He even has a Microwave which creates the inventions for him.
 * Red Green of The Red Green Show aspires to this. Usually he doesn't make it and his inventions backfire horribly, but on rare occasions they actually work. A forklift built out of a K-car is truly a wonder to behold.
 * It doesn't come up much, but it's implied that Joel Robinson, of Mystery Science Theater 3000, as well as a number of other characters on the show are this. In the theme, they even say that Joel used the "special parts for controlling where movies begin and end" to create the four seemingly-sentient robots, three of whom watch movies with him.
 * The original premise of the show was that the Mads (mad scientists) stranded Joel in space specifically so that they could steal his inventions. In several episodes, during the Invention Exchange, Joel complains when the Mads steal his ideas. The Invention Exchange didn't really last long after Joel left, however... instead of inventing stuff, Mike would fill his time by either confusing the Mads (for example, by pretending to be a drive-though restaurant, or shilling them "bold" BBQ sauce), or attempting to escape (for example, challenging Pearl to a game of three-card Monty).
 * Just about everyone in the town of Eureka at some point, on the television show Eureka, except for Sheriff Carter.
 * In the Torchwood episode "Fragments", it's revealed that Toshiko Sato once built a working sonic screwdriver from incorrect blueprints.
 * This is what got her hired, actually. The alternative was life in prison.
 * Scholar Mek of Spellbinder began the second series by designing and building a transdimensional boat... when he was supposed to be making a set of musical jewels for the Dragon Lord.
 * As noted above, Artemus Gordon on The Wild Wild West cobbled together all sort of useful gadgets for his partner James West to use.
 * The crew of MythBusters should DEFINITELY count, especially Grant and Jamie.
 * Claudia Donovan from Warehouse 13. H.G. Wells is a villanous version of the tropes.
 * Siroc from Young Blades is known for his (frequently anachronistic) inventions, including a submarine, a machine gun, a metal detector, a bomb concealed in a hollowed-out watermelon, and a machine that generates static electricity by turning a wheel of artificial feet wearing socks so that they rub against a static-generating material.
 * Fred on Angel fits this, especially with her improvised flying blade of beheading in season 3 "Fredless".

Magazines

 * One of the Mascots of Top Secret is Prof. Dzemik, who originally was facetiously created as an expert who responded to the readers' technological questions, and also starred in the magazine's comics where he was usually a plot device who invented the time machine or exposited on a dimensional transporter that was the basis of a story's plot.

Oral Tradition, Myths and Legends

 * Vulcan/Hephaestus/Hephaistos in Classical Mythology. Of note are the trap-bed he made to catch Aphrodite cheating on him with Ares, the Mechanical Horses he built to pull his chariot, the Robot Girl maids he built to serve him and sing for him, the gold and silver lions and dogs he built to protect the palace of Alkinoos, Eros' bow and arrows of love and hate, Hermes' winged sandals which allow him to fly, Helios' chariot, and mechanical tripods which could walk to and from Mt. Olympus.
 * The Dwarves in Norse Mythology. Of note regarding the things which they built are Gullinbursti, a mechanical boar made of gold which could travel incredibly fast both over land and underground, Thor's hammer Mjöllnir, which could cause lightning to strike when thrown, and be shrunk down to a tiny size, Odin's spear Gungnir, which could strike any target it was thrown at, Tyr's ship Skidbladnir, which could be shrunk down to a tiny size, a wig for Thor's wife Sif which grew just like real hair, and, most intriguing and disturbing of all, the dwarf brothers  Fjalar and Galar made magic wisdom-granting mead  from a man's blood.

Tabletop Games

 * Urza and Mishra, the Brother Artificers of Magic: The Gathering, build enough weapons and doomsday devices in their lifetime to leave their world a nearly-blackened cinder by the end of their lives.
 * From the first incarnation of the World of Darkness RPG:
 * The Sons of Ether from Mage: The Ascension are Mad Scientist in the purest sense, with oft-retro aesthetics ranging from Raygun Gothic to Victorian-esque Steampunk. The Virtual Adepts were technomantic computer hackers with Urban rebel Cyberpunk flair, doing in the real world what Neo did in The Matrix. And of course there was the Technocracy, which had lots of gadgeteer genius engineers of their own, especially among the Iteration X; the difference being that the Technocracy encouraged a mass-producible, utilitarian type of gadgeteering, while the Sons of Ether used idiosyncratic gadgets that may or may not work for others, and the Adepts fell somewhere in between.
 * One tribe of werewolves, the Glasswalkers, in Werewolf: the Apocalypse had adapted to modern times and learned to use their spirit magic to talk to the spirits of machinery and urban landscapes.
 * The Nockers from Changeling: The Dreaming are changelings whose fairy souls are drawn to technology, although their curse means every gadget they build will have some sort of hidden flaw, which sometimes results in explosions; the evil counterparts of the Nockers are called Gremlins, who in their Fairy self look nothing like the creatures in the movies of the same name but more like small pointy-eared people with green skin and sharp pointy teeth... and they grin a lot, especially when they've just planted a booby-trap somewhere or sabotaged a piece of technology.
 * Nockers are also capable of scaring a piece of machinery into working temporarily by cussing at it.
 * In the second incarnation of the World of Darkness:
 * Werewolf: The Forsaken has the Iron Masters, who tend to stay close to humanity and urban habitats. They have an affinity for Technology Gifts that, at the highest level, allow them to make a technological device out of the base materials (that is, a circuit-board out of plastic and sand).
 * Mage: The Awakening has the Free Council, modernist mages whose studies take them towards examining magic with a scientific lens—often resulting in SCIENCE!!!
 * Changeling: The Lost has the Wizened, who were kept as caretakers, craftsmen, and busybodies for the True Fae. They have an affinity with Contracts that allow them to manipulate and construct (or deconstruct) machinery; the top level of one set allows them to make a hovercraft out of a go-kart and an inflatable raft.
 * And then there's the fanline Genius: The Transgression, where most of the player characters are these, capable of making inventions that bend the laws of physics to the breaking point. Powerful Geniuses are easily the most effective at gadgeteering, whipping up an entire fleet of spaceships is possible.
 * The Mad Scientists in Deadlands are similar to the series example above; the devices they make barely . The power behind their science-breaking steampunkness is . Well, not Hellstromme, he knows exactly what he's doing.
 * The Artificer base class from the Eberron campaign setting of Dungeons & Dragons is a magical version of the Gadgeteer Genius.
 * GURPS has two levels of this. Gageteers can build things that break the laws of physics if they have lots of funding. Quick Gageteers can do the same thing in half the time with rubberbands and cheese.
 * And their options get even wilder if the Gizmo advantage is also taken. For a Gadgeteer character, that means that at a crucial moment, he or she can build exactly what they need on the spot. (Alternatively, it can also mean happening to have just the right gadget in his or her pocket.)
 * In Warhammer Fantasy the Skavens clan Skyre is a group of giant rats numbering hundreds of thousands if not millions of Gadgeteer Geniuses. The engineers of the empire follows this trope quite good as well. The dwarfs might at first appear like this but their constructions aren't that improbable and most are old engines based on experience and new inventions are rare.
 * The Ork Mekboyz of Warhammer 40,000 might as well be gods of this trope, being able to construct Humongous Mecha out of a mound of scrap metal and a hot water heater. Not to mention every other piece of Ork technology from cars to guns to back scratchers are made in this way. Since this knowledge is bred into their DNA, and they aren't really that bright, they use latent psychic powers to cover up flaws.
 * And make Da Red Ones Go Fasta!
 * The D20 supers game Godlike likewise has gadgeteers turn out to actually have nonsensical gadgets that only work because their "inventors" believe they do, most likely as a way to prevent a Reed Richards Is Useless situation.
 * Traveller: The Terran Confederation is this in Intersteller Wars. When they first meet the Vilani they are thousands of years behind. However they surpass them in less then two hundred years.

Toys

 * Bionicle: Nuparu, Avak, and Telluris

Video Games

 * If a character in any Final Fantasy game is called Cid, two things are almost certain: 1. He's a Gadgeteer Genius and 2: His specialty will be Airships, for example:
 * Never seen, but Cid of the Lufaine in Final Fantasy I (at least all it's remakes) was the inventor of the first airship.
 * The very first Cid appears in Final Fantasy II, who offers taxi service with his airship to the heroes.
 * Final Fantasy III gives us Cid Haze, skilled enough to convert a Cool Ship into a Cool Airship.
 * Cid Pollendina of Final Fantasy IV was the first playable Cid, who refuses to let little things like riding a nuke into an enemy vessel and an Avalanche of millions of tons of rock and magma stop him from fixing up your airship. He's also a Cool Old Guy/Boisterous Bruiser which would become recurring Cid traits.
 * Final Fantasy V's Cid Previa builds airships, surprise surprise, and makes Crystal Power Enhancing... Thingies.
 * Cid Del Norte Marquez from Final Fantasy VI oddly enough doesn't work with Airships, but is no less of a Gadgeteer Genius seeing as he invented Magitek and designs Powered Armor, weapons, and even pseudo-genetic engineering.
 * However, if you go out of your way to visit the crashed Blackjack after Terra and Locke leave Vector on the way to the Crescent Island, you can find Cid on board offering to help Setzer repair it, claiming he has some prior experience with airships. Setzer politely turns him down.
 * Cid Highwind of Final Fantasy VII fame is probably the most well known on this list. He does the same in the Kingdom Hearts games, except he doesn't fight. or smoke(he gets a toothpick). Or swear.
 * Cid Kramer of Final Fantasy VIII put up part of the money used to rebuild the mass people mover that would eventually become Balamb Garden, which functions as the party's primary mode of transportation early in the story, and negotiates with a city of engineers to help actually create it to his specifications.
 * Cid Fabool IX of Final Fantasy IX. His proficiency at designing airships has led Lindblum to become Gaia's prominent air power. He also spends some time as a frog after an argument with his wife.
 * Final Fantasy X's Cid. He builds airships and he's loud and boisterous. He doesn't really bring anything new to the table.
 * His daughter, Rikku counts as well with her "Mix" Overdrive.
 * Final Fantasy XI's Cid is, fittingly enough, the most prominent engineer and inventor in Vana'diel.
 * Final Fantasy XII's Cidolfus Demen Bunansa (Dr. Cid for short) is the first Cid to actually feature as a fully fledged villain, being the Mad Scientist responsible for most of the airships and weapons built for the Archadian Empire.
 * Jennifer from Disgaea created super-robot Thursday at the age of 5.
 * Billy Blaze, alias Commander Keen, from id Software's Commander Keen series. Commander Keen built a spaceship in his garden, made from old soup cans, a joystick, a car battery, a vacuum cleaner and a bottle of Everclear.
 * Andy, from Heart of Darkness, is pretty much a clone of Billy Blaze above.
 * Lucca in Chrono Trigger.
 * Little Mad Scientist girl Penny Crygor from Wario Ware: Smooth Moves fits the trope to the letter. She's also totally adorable.
 * Max from Dark Cloud 2 can make items out of pretty much anything he sees. He just needs to capture photos for inspiration.
 * Lash from Advance Wars, who combines this trope with being an Enfante Terrible, much to the protagonists' dismay.
 * Shinra from Final Fantasy X-2, although his entire race is exceptionally technologically advanced, the rest of the game world having been Luddites until shortly before the game's beginning.
 * The Vances from Half Life 2. Eli built a robotic dog for his daughter, Alyx. Over the years, she upgraded Dog into a super-strong, semi-sentient Lightning Bruiser.
 * Jeff Andonuts of EarthBound. He's capable of using laser guns, bombs and the like, and can turn various broken irons, antennas, harmonicas, and the like into powerful weapons and battle items overnight. And did we mention that he's only thirteen years old?
 * Tron Bonne and Roll from Mega Man Legends.
 * Ciel from Mega Man Zero. And the two above examples seem like amateurs compared to her. Her accomplishments? Creating a perfect replica of X (Cain certainly couldn't, partially why mavericks exist), she created an energy system to solve the energy crisis that is not only effective but just beautiful (take a look at the reactor of the Guardian airship from ZX!), and she made Biometals to match Master Albert's, but also added the dual Mega-Merge feature. And she created Copy-X when she was nine years old. Don't believe me? Read the MegaManZero Complete Works.
 * Area from Street Fighter ex2 plus. While they didn't give her much of a story, they did say that she was a greater inventor than her father.
 * Miles "Tails" Prower and Dr. Robotnik from the Sonic the Hedgehog games.
 * Bentley and Penelope from the Sly Cooper series.
 * The Engineer of Team Fortress 2 is capable of creating NASA-level sentry turrets and teleportation devices using nothing more than his wrench and scrap metal collected from weapons dropped by the recently dead.
 * Don't forget his laws-of-thermodynamics-be-damned dispenser, and the fact that he can make one from scratch using the raw metal of a butterfly knife. Which he invented. In the 60s. Then again, he does have 11 PHDs, so it's a little justified.
 * Butterfly knife be damned that man can make a physics defying dispenser out of a wooden baseball bat.
 * Or an empty glass bottle!
 * Or a glass jar filled with urine!
 * He also built himself a robotic hand to replace his missing right hand. A hand that he cut off so he could replace it with a robotic hand.
 * This trope is the defining characteristic of Gnomes in World of Warcraft. Gnomish tinkerers are famous for inventing just about anything, including (but not limited to) helicopters, robots, guns, and even some mechanized melee weapons. Players can take the "Engineering" profession, which allows them to embody this trope. The profession even allows the player to create Mad Scientist style goggles.
 * Although true to Gnomish tradition, player made inventions have a nasty tendency to backfire through explosions, accidental size modification, poultryfication, and teleporting you far above the ground. If it does not do any of this it is either a bomb, has a massive cooldown time, or is a robot or something that works once before breaking.
 * Another gnome from a completely different universe/game (and a definite case of Our Gnomes Are Weirder), Jan Jansen from Baldur's Gate 2 starts the game with a crossbow (including bolts), gloves, boots, and goggles of his own design, most of which give him a big bonus to his thieving skills. Originally, he would have invented more gadgets as the game went on, but this was sadly scrapped due to lack of development time.
 * Grubb from Septerra Core. He built several robots of different types out of rubbish thrown down from Terra 1.
 * in The Nameless Mod; he built an inanimate object with the powers of a board admin, something couldn't do, hence why he was.
 * Edgar from Final Fantasy VI designed many of the machines used and exported by his kingdom, including the weapons he uses in battle, most infamously his giant chainsaw. His Job class is described as "Machinist" and, where everyone else is wielding swords, knives, or staffs, Edgar is the only one holding a huge gun.
 * Purge from Space Channel 5 Part 2.
 * Momo from Breath of Fire III.
 * Nono the airship mechanic from Final Fantasy Tactics Advance and Final Fantasy XII. In Final Fantasy Tactics A2 Hurdy explained that Nono built his own airship called "Brilliante I."
 * Bill from Pokémon Red and Blue, who invented the storage system, as well as his colleagues who helped him. In the manga, he also invented the Vs. Seeker.
 * Carl, your chief engineer in Mechwarrior 4 has a reputation as one. The saying goes "Give Carl a hundred tons of steel wool and he'll knit you an Atlas overnight."
 * Professor E. Gadd from the Super Mario series. Also, Shy Guys, who count as Gadgeteer Genius Mooks. Luigi also becomes this as Mr. L.
 * The steampunk RPG Arcanum allows players to be gadgeteer geniuses, eventually building such things as steam-powered robots, staffs that shoot lightning and a device that can revive the dead.
 * The whole Bui bui species from Loco Roco series. To lesser extent, Mui mui too.
 * Touhou has Nitori and the Kappa race in general. In a setting that has a medieval level of technology, Nitori has managed to create things like optical camo suits.
 * The Gadgeteer is an actual class in Wizardry 8, and it's just as powerful as you'd expect. Thankfully the rarity of components means that you can't really have more than one in the party, which keeps the game from becoming unbalanced.
 * Gadgeteering exists as a power set in the MMORPG Champions Online. One of the abilities being an 'Experimental Ray' which has a chance for various effects, including turning the target into a teddy bear.
 * The Gadgeteer is also the name of a class in Twilight Heroes - they make many of the gadgets and devices that they use in combat.
 * Funky Kong; he can make helicopters, watercraft, and guns out of Bamboo Technology. All while being a Surfer Dude.
 * Puck of Vanguard Bandits is capable of repairing the strongest and oldest ATACs in record time and can keep them in working order with the smallest of resources.
 * Unwritten Legends has two classes based on gadgeteering, making the characters either this or at least the Genius Ditz
 * Victoria Van Bathysphere from LittleBigPlanet 2. The later portion of her level is an Eternal Engine and she made a robot army.
 * Eagle Eye Mysteries: Word of God says that Jennifer Eagle's character was created specifically for her to be this. In-game, she built the Eagle Eye Detective Agency's TRAVIS hand-held computer, and is rather picky about who gets to wield it (only Eagle Eye members have the privilege).
 * Solatorobo has Merveille, who is credited with single-handedly raising the bar for Kurvasz Mini-Mecha design. The shopkeeper Suzette and Red's sister Chocolat are both Wrench Wenches.
 * The Lombaxes from Ratchet and Clank are an entire race of Gadgeteer Geniuses. Ratchet himself was able to build a functioning space ship out of A BOX OF SCRAPS! spare parts IN A CAVE! on Veldin simply by following Gadgetron's voice prompts (not to mention the list of his wacky inventions that Clank rattled off), and the Lombax Secret is in fact According to the Smuggler, Lombaxes can't leave any invention the way they found it and are forever tinkering.

Web Comics

 * Agatha Heterodyne of Girl Genius, and the other Sparks (Mad Scientists). An example of Schizo-Tech because Sparks are able to screw with the laws of physics. Examples include electrical lightning moats, cloning pods, Death Rays, giant airships, autonomous robots and Frankenstein monsters in a world that is otherwise at the tech-level of the 19th century. (That's her in the page image. Yes, that is a coffee maker. No, you don't want any coffee from it.)
 * Yes you do! If you haven't seen Vanamonde von Mekkhan's description of this coffee, you will find the need to find the Foglios and have them tell you how they came to our universe so we can go there and get some. The only downside is you'll never be able to fully enjoy other cups of coffee again.
 * Kat from Gunnerkrigg Court builds an antigravity generator out of a thermos and coat hangers for the school Science Fair. She didn't see this as anything special, and built it simply in order to allowe her protein synthesis experiment to work properly. Much to her chagrin, nobody cared very much about proteins, but were fascinated by her anti-grav machine. Later, she converts it into a personal aircraft.
 * Tedd from El Goonish Shive is a male version of this trope. Grace, the squirrel-girl girlfriend of Tedd, has her moments as well.
 * Scarlett from Sequential Art is either this, or an Idiot Savant. Several strips indicate that she'd be an engineering genius were it not for her crippling case of ADD.
 * It later turned out she is actually one-fourth of a biocomputer gestalt, she is a lot more competent when she's with her "sisters"
 * Though they do have a disturbing tendency to make things that explode... including bug nets and self-motivated slinkies. That explode.
 * In The Adventures of Dr. McNinja, Sean "Dark Smoke Puncher" McNinja, the brother of Dr. McNinja, is shown to be particularly technologically adept and his own brother noted that his own Mecha-Mooks are more dangerous than normal.
 * Molly from The Inexplicable Adventures of Bob. An artificially (or rather, accidentally) generated creature, she is less than a year old and has the common sense of a little girl, but is quite capable of building a giant robot out of a milking machine, and an interstellar transmitter out of an umbrella and a Speak n' Spell.
 * Her sister Galatea is no slouch, either.
 * Thomas the Cat from Penny Arcade, as seen here and here.
 * Not to mention Annarchy, especially in the Rain Slick Precipice of Darkness games where she upgrades your weapons and builds a . Also meets the female and school-age requirements.
 * Dust Puppy in User Friendly wrote Erwin the Artificial Intelligence overnight, in Cobol, only 53 days after Dust Puppy himself was born.
 * Sluggy Freelance's Riff has built several robots, a device for opening gates to other dimensions, the Omnitaser Supreme, and a staple remover with a 100 feet range.
 * A more specific version, but Megatokyo's Largo can build a computer out of almost anything, including cereal boxes.
 * Sev'vil and Anira in Juathuur are the greatest scientific minds in the world.
 * The titular pair from Casey and Andy?
 * Dr. Nonami stars a young female scientist who invents a variety of machines to fight evil.
 * Doc and Roger from The Whiteboard tend towards this, triply so (at the very least) if alcohol is involved. Notable inventions include a fusion-powered paintball gun capable of firing through time, and a micro air compressor which runs on nitroglycerine as petrol isn't powerful enough.
 * Voodoo Walrus has a "house badger" by the name of Professor Kaboodles who has seemingly evolved in the background from being a simple pet badger to a full on goggle and lab coat wearing inventor. Though no one notices. Even when he's shooting lasers at floating pygmy cows.
 * Walter from Dubious Company, regularly upgrades the ships he steals with complex Magitek, and is the go-to-guy for Techno Babble. His first on panel instance of this is in the shipwrecked arc, where he built a fully-furnished house in the course of an afternoon without tools. It was also a Visual Gag about his animal instincts.
 * Equius Zahaak from Homestuck uses his mechanical skills to build new body parts for his wounded allies. He also builds robots for various personal uses.

Web Animation

 * Sudoku from Banana-nana-Ninja! has built a Transformation Ray and a Swiss Army Weapon (the Omni-Functional Kitchen Gadget, an all-purpose kitchen tool that can transform into a Humongous Mecha).

Web Original

 * The various gadgeteers (follows the laws of physics) and devisors (considers them more of a guideline) of the Whateley Universe have this as their mutant talent. Ironically, Word of God has canonically stated that even they can't actually make a giant robot that works. Not that this keeps the relevant perpetual school project nicknamed "Tiny Tim" from having its own Crowning Moment of Awesome during the Halloween battle...
 * Makes-Things, Techno-Dann, in Protectors of the Plot Continuum. Technically, anyone who works for the Department of Sufficiently Advanced Technology can qualify.
 * The Web Serial Novel The Descendants has a lot of these: Codex, Tink, and (at least in the backstory) Chaos all serve this role, as do many of the villains—most notably Maven.
 * The Podcast Critical Hit has two: the PC Randus du Thane, played by Brian, and the NPC Thony.
 * A staple villain type in Super Stories, usually with their own, restricted specialty. Veldron is a whiz at electronic circuitry, Clockwork is brilliant with medium-scale engineering such as, well, clockwork, and Devnull is a programming and hacking genius.
 * There's also the Masks universe, where this is one of the mutant powers, besides for instance Bricks (really tough and strong) and Flyers.
 * This is a super-power in the Global Guardians PBEM Universe. Some Gadgeteer Geniuses have only the power to make one very, very advanced device (Roland Jaffe created an iPod-sized battery that could store more electricity than a ten-foot-high pile of car batteries, and Peter Dansker, a technician for Lucent, built a truly sentient android over the course of a weekend), while others are able to toss out new technology as easily as they can breathe.
 * In the web novels Trinton Chronicles there are two characters who fit this, one is Robert who took actual schooling on robotics and the other is Brandon who's super power actually allows him to understand machines.
 * Essay (hero), Gimble (neutral) and Triton (villain) are notable examples in the Academy of Superheroes universe. Gimble is notable because she makes physics-violating tech that everyone can use—even Anchors.
 * The League of STEAM boasts several, especially Crackitus Potts.

Western Animation

 * Phineas and Ferb:
 * Phineas and Ferb.
 * Dr. Heinz Doofenshmirtz. Despite being a normally Harmless Villain, he is capable of building -inators that are as impressive as the inventions of the title characters.
 * Also, the Fireside Girls, led by Isabella. They're usually just helping the boys out, which is impressive in itself, but they can build a Time Machine.
 * Jimmy Neutron is only a kid, but he has already surpassed any known scientist in capablity. Each episode focuses on one of his invention although his inventions usually fall pray to Flowers for Algernon Syndrome.
 * Gadget Hackwrench from Chip 'n Dale Rescue Rangers.
 * Dexter's Laboratory has a gadgeteer for its main character.
 * Codename: Kids Next Door.
 * They make holographic projectors out of steam engines and lasers out of a flashlight, a piece of wood, and a bottle.
 * AND SPACESHIPS!
 * If you're looking for a person example, Numbuh 2 would be your man. You just have to get past his Punny way of life.
 * Edd from Ed, Edd 'n' Eddy. He makes an industrial-grade excavator out of junk he found around his neighborhood.
 * Professor Von Slickstein of Inspector Gadget, who even incorporated gadgets into the title character's body. T
 * The Inspector's niece and dog, Penny and Brain, are the more competent gadgeteers, though they are just as likely to become the Damsel in Distress (both of them are subject) or Wrongly Accused (Brain, while simultaneously being the Damsel sometimes) while Gadget plays the Spanner in the Works.
 * In addition to commentary, Stone Cold Steve Austin provided this service in the original run of Celebrity Deathmatch. His technological expertise yielded a fully-functional cloning machine (used to combine DNA from dead celebrites into fighting mutants) and a rickety time machine (used to bring to life such matches as The Three Tenors vs. The Three Stooges).
 * Gear from Static Shock, who initially thought his power was rather lame: "How am I supposed to fight supervillains, think them into submission? All I can be is your Mega-Mechanic." Which turns out to be a great way to fight supervillains.
 * Sandy Cheeks from SpongeBob SquarePants, especially in the later seasons.
 * Kani on Sushi Pack fits the bill, although others have tried to steal credit for her inventions on occasion.
 * The Spectacular Spider-Man has two. Adrian Toomes is the inventor of the Magnetic Air Transport System, a suit of Flight-capable Powered Armor that he uses as the Super Villain Vulture to antagonize Norman Osborn for stealing his designs. Chameleon's henchman Mason (aka, the Tinkerer) is responsible for developing all the Shoe Phone technology the Chameleon needs for his work as a Master of Disguise.
 * Widget from Wow! Wow! Wubbzy!.
 * Jack and Maddie Fenton in Danny Phantom seem to fit this trope, with their inventions being proven inoperable by a normal person, or even The Guys In White, due to the quirks because of said "tin cans and an old transistor radio" method of construction.
 * Professor Utonium from The Powerpuff Girls creates things like a supersuit or a giant robot or a car that can turn into a giant robot.
 * ...or superpowered kindergarteners.
 * Jérémie from Code Lyoko. His gadgeteering occurs more in the virtual world, however, as he is the primary programmer and the one who is most adept at using the Supercomputer. However, it is a confirmed fact that he can build robots, participating in a robot competition in Season 1. He also created an EMP bomb in episode "Ultimatum," which has efficiently stunned a XANAfied person at this occasion.
 * Unfortunately that EMP bomb in "Ultimatum" also fried Ulrich's cell phone, preventing the news that Yumi and Odd were alive and rescued from getting back to Jeremie. Ah well; easy come easy go I guess.
 * Wade from Kim Possible is able to build more or less anything that the plot demands. And the Tweebs that were able to really pimp Kim's car. The three of them are 10 years old...
 * On the villainous side, Motor Ed is a mechanical genius. Seriously!
 * In his "bad boy" mode, Ron Stoppable is this. It's even latent in his "good" mode, when he builds a weapon (at Drakken's insistence) IN A LAIR, from A BOX OF SCRAPS!
 * Tanya from The Mighty Ducks is introduced as "She was so smart, she actually knew how to program a timer on a VCR!" As well as building the team's machines and blowing up those of the enemy, she used a wrist mounted chainsaw in battle. She also had a stutter due to her brain going so fast (and trying to explain things in terms the others could understand).
 * Ginger Snap from Strawberry Shortcake.
 * Donatello from Teenage Mutant Ninja Turtles.
 * Tinkerbell is one of these in her origin story movie. This actually comes from the original JM Barrie Peter Pan: She mended pots and kettles, at least. The name really does come from her being a tinkerer.
 * Grumpy from Adventures in Care-a-Lot straddles the line between this and Bungling Inventor. He apparently built an entire theme park at one point, not to mention a cloning device, among many others, but his inventions sometimes turn on him (i.e. the clone cloned itself and both clones kicked him out for not being "Grumpy" enough) or fail because of (unwanted) help from Oopsy.
 * The Geek from Sam and Max Freelance Police fits the original mold perfectly, as a young genius girl who built a gigantic robot Max in her underground lair.
 * Rattrap in Beast Machines was stripped of all weapons upon being reformatted, so compensated by developing all sorts of handy devices to stop the Vehicons.
 * AJ from The Fairly OddParents.
 * Froggo from Histeria! was always asking for things because, as he put it, "You've got your inventions, and I've got mine."
 * Velma Dinkley produces a number of remarkably sophisticated pieces of equipment in her spare time in What's New, Scooby-Doo? In the same series, Fred also makes a few minor modifications to the Mystery Machine, such as equipping it to transform into a submarine at the press of a button.
 * Similar to Fred's modification of the Mystery Machine, Alan of The Amazing Chan and The Chan Clan programmed the iconic Chan Van to be able to transform into just about anything. Even a dynamite truck.
 * Tech E. Coyote manages to cobble together a model of the city in his spare time. This model comes complete with trains that actually run on time. When not in his spare time, he makes the heroes' arsenal.
 * Don't forget Wile E. Coyote in the Bugs Bunny cartoons on occasion, though mostly he used Acme Products.
 * Wakfu's Nox, a brilliant (if unsuccessful) clockmaker, had a bit of this going on before he went utterly crazy. And then he went on to prove just how scary an evil Gadgeteer Genius could be.
 * In the Ruby-Spears Mega Man show, Roll modified her Utility Arm herself. This included such appliances as a vacuum, a blender, a circular saw, and modifying a baking sensor to detect earthquakes.
 * Tracey McBean
 * Philly Phil from Class of 3000.
 * Coop from Megas XLR tuned up a Humongous Mecha until it worked better than the original, even despite all the parts he keeps breaking on account of not being all that bright besides.
 * The Mechanist from Avatar: The Last Airbender.
 * Wheeljack, from Transformers! How has he not been mentioned yet? He created the Aerialbots and the Dinobots, and while some of his inventions don't quite work out, in the, ah, explode-y sense.. his fuel pump is in the right place. I mean, he also invented lots of useful things! Like the Immobilizer, which worked great until it blew up, and the Negavator, which worked great until IT blew up, and that bomb they used one time, which was supposed to blow up, so it DEFINITELY worked great, and I think I'm starting to sense a trend here...
 * Gretchen Grundler from Recess

Real Life

 * The book The Boy Who Harnessed The Wind is about a real-life example of this. William Kamkwamba, a fourteen-year-old Malawian boy, was forced to drop out of school because his family could no longer afford the tuition. Using some books from a foreign-aid funded library and parts from a scrapyard, he constructed a fully functional windmill to run appliances in his family's home, largely creating the design from scratch.
 * Wolfgang von Kempelen (Kempelen Farkas) was a real life example from the 18th century, known for creating, among other things, a speaking machine and a chess playing 'automaton'. The later required an operator sitting inside and controlling the puppet through an elaborate mechanism, and using several other mechanisms to conceal himself when the machine is opened up, creating the illusion that the whole structure is fully mechanical.
 * Wu Yulu is a 46-year old farmer from a rural area of China near Beijing. While he has very little in the way of formal education, he has over the past thirty years built over 26 robots to do everything from light cigarettes, to scale walls, to drive rickshaws, building them out of scrap metal. In true Mad Scientist tradition, he nearly drove his wife to divorce, plunged them both into tremendous debt, destroyed his home and scalded his face with acid. All For Science!! Or at least his crazy hobby.
 * Draper Kauffman, the head of the Underwater Demolition Teams (World War 2 Seals effectively) was good at gadgets and had a number of skilled gadgeeteers in his crew. He was once a bomb tech during the blitz, and latter planned the breeching of obstacles at Saipan.
 * Victorinox is a corporate gadgeeteer genius specializing in making one of Switzerland's most famous products.
 * Swiss in general are famous for gadgets. They make watches after all and though they did not actually invent the cuckoo cloak they could have.