A crystal radio is a common enough science fair project, but the problem is, there isn’t much on anymore. The answer is, of course, obvious: build your own AM transmitter, too. AM modulation isn’t that hard to do and [Science Buddies] has plans for how to build one with a canned oscillator and an audio transformer.
We don’t imagine the quality of this would be so good, but for a kid’s science project it might be worth a shot. Maybe something like “What kind of materials block radio waves?” would be a good project statement.
The Golden Age of Radio Shack was probably sometime in the mid-1970s, a time when you could just pop into the local store and pay 49 cents for the resistors you needed to complete a project. Radio Shack was the place to go for everything from hi-fi systems to CB radios, and for many of us, being inside one was very much a kid in a candy store scenario.
That’s not to say that Radio Shack was perfect, but one thing it did very well was the education and grooming of the next generation of electronics hobbyists, primarily through their “Science Fair” brand. Some of us will recall the P-Box kits from that line, complete projects with all the parts and instructions in a plastic box with a perfboard top. These kits were endlessly entertaining and educational, and now [NetZener] has recreated the classic neon “Goofy Light” P-Box project.
As it was back in the day, the Goofy Light is almost entirely useless except for learning about DC-DC converters, multivibrators, RC timing circuits, and the weird world of negative resistance. But by using the original Science Fair instructions, compiling a BOM that can be filled from Mouser or Digikey, and making up a reasonable facsimile of the original P-Box chassis, [NetZener] has done a service to anyone looking for a little dose of nostalgia.
Sometimes you have to start out with big goals. Ninth-graders [Finja Schneider] and [Myrijam Stoetzer] are aiming to make a magnetic field scanner that would be helpful in finding large underground metallic objects, like unexploded WWII bombs that pose a real threat whenever a new parking garage is excavated in Germany. But even big goals have to start out somewhere, so they’re gaining experience with the sensors and the math necessary to recreate 3D magnetic flux vector fields on household objects like sawblades and magnetized screwdrivers.
For their science-fair project, [Finja] and [Myrijam] took a mid-80s fischertechnik “toy” 2D scanner kit, mounted a 3D magnetic sensor to it, and wrote some firmware to scan around and pass the data back to a computer where they reconstructed the field lines and made some nice visualizations. Along the way, they tried a number of designs, from a DIY chassis on carbon-fiber rails to sensors with ferrofluid. They document their successes and failures equally nicely in their lab report (PDF, German). You can get a lot of the gist, however, from [Myrijam]’s blog and their Hackaday.io entry.
You might also recognize [Myrijam] from her work with [Paul Foltin] on their eye-controlled wheelchair interface. These are some really cool projects! We’re excited to see how they develop, and are stoked that the future of hacking is in such capable hands.
Hacking has always brought more good to the world than not hacking. The successful efforts of the Allies during World War II in deciphering the Enigma machine output still reminds us of that. Today, the machine is a classic example of cryptography and bare-metal computing.
For her science fair project, [David]’s daughter had thoughts about dipping eggs in coffee, or showing how dangerous soda is to the unsuspecting tooth. Boring. Instead she employed her father to help her build a Morse Code waterfall.
[David] worked with his daughter to give her the lego bricks of knowledge needed, but she did the coding, building, and, apparently, wire-wrapping herself. Impressive!
She did the trick with two Arduinos. One controls a relay that dumps a stream of water. The other watches with an optical interrupt made from an infrared emitter and detector pair to get the message.
To send a message, type it in the keyboard. The waterfall will drop spurts of water, and then show the message on the decoder display. Pretty cool. We also liked the pulse length dial. The solution behind the LEDs is pretty clever. Video after the break.
The red cylinder shown in the image inlay is his test rig. It is covered well on his project site linked above. You just need to click around the different pages using the navigation tiles in the upper right to get the whole picture. The propulsion module uses water sprayed out the nozzle to push the enclosure forward. The hull is made of PVC, with a bladder inside which is connected to the nozzle. The bladder is full of water, but the cavity between it and the hull is full of air. Notice the plastic hose which is used to inject pressurized air, squeezing the bladder to propel the water out the nozzle. Pretty neat huh?
We think [Alex’s] work stands on its own. But we can’t help thinking what the next iteration could look like. We wonder what would happen if you wrapped that bladder in muscle wire? Would it be strong enough to squeeze the bladder?
You can see all fifteen finalists at the GSF announcement page. Just don’t be surprised if you see some of those other projects on our front page in the coming days.
If you’re around the Washington, DC metro area next weekend, here’s something for you. It’s the USA Science and Engineering festival, and if you’ve ever wanted to talk to [Adam] and [Jamie] from Mythbusters, [Bill Nye], and several astronauts, this is where you should be next weekend.
This is the second USA Science and Engineering festival. The first festival, brought to bear because of an act of congress. The last festival was highly successful (and fun), so we can’t wait to see the reports from next weekend roll in. This time around, there will be scale models of the Orion Service Module, an F-22 cockpit Demonstrator, and a demonstion of an F-35 taking off vertically. Yep, Lockheed Martin is hosting this festival, but it’s still cool.
Even though the website makes it seem this festival is geared towards children, we’re sure we’d have a blast visiting. Here’s a solution: borrow a niece or nephew and show them what engineering can do.
We have to note you can also visit the NASA Goddard Space Flight Center while you’re in DC. It’s just a short Metro ride (with a bus transfer) from the convention center where the festival will be taking place. We highly recommend the tour of the facility. If anyone knows if you can see the space shuttles Discovery and Enterprise at the Udvar-Hazy center next weekend, drop us a line. We’ll amend our DC ‘look at cool stuff’ recommendations.