A Self-Driving Bicycle Is Something To Marvel At

June 10, 2021 by Zoe Skyforest 44 Comments

One of the most annoying things about bicycles is that they don’t stay up on their own, especially when they’re stationary. That’s why they come with stands, after all. That said, if you had plenty of advanced electronic and mechanical equipment fitted to one, you could do something about that, and that’s just what [稚晖君] did.

The video of the project comes without subtitles or any translation, but the gist of it is this. A reaction wheel is fitted to the seat tube, along with a motor which can turn the handlebars via a linkage attached to the head stem. There’s also a motor to drive the bicycle forward via a friction drive to the rear wheel. Combine these with an inertial measurement unit and suitable control system, and you have a bike that can balance while standing perfectly still.

The performance of the system is impressive, and is even able to hold the bike perfectly upright while balanced on a fence rail. Thanks to an onboard camera and LIDAR system, the bike can also drive itself around with no rider on board, which is quite a spooky image. Find a way to do the same while hiding the extra mechanics and you’d have one hell of a Halloween display.

Similar projects have been attempted in the past; we featured a self-balancing bike built as a university project back in the distant past of 2012. Video after the break.

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An Explanation Of A Classic Semiconductor Riddle

June 10, 2021 by Zoe Skyforest 14 Comments

Back in 1996, Bob Pease posed an experiment in an April Fools column. “Take an ordinary NPN transistor, ground the base, pull the emitter up to 12 V with a 1 KΩ resistor and measure the collector voltage referenced to ground.” Do the experiment, and you might be surprised to find a small negative voltage present on the collector. [Filip Piorski] has always loved the riddle, and has explained how it works in a Youtube video.

The key to the trick is the breakdown voltage of the transistor; normally somewhere around 7-8 volts for a typical small NPN transistor. At this point, where the base-emitter junction enters the breakdown regime, it begins to emit light. This light actually travels through the silicon lattice, where it reaches the base-collector junction, which acts like a photodiode under the right conditions. This generates the negative voltage seen at the collector under these conditions.

[Filip] goes on to try the experiment with a TO-3 transistor with the top cut off so he could visualise the effect in action. His photos, taken in a dark room, show tiny flecks of light appearing at spots on the silicon die. If you’ve got more insight on the effect in action, drop a comment below.

It might seem like a simple curiosity, however silicon junctions and their light emissions are an area of active research in semiconductor physics. Video after the break.

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Automatic Chessboard Lets Online Players Move The Pieces

June 10, 2021 by Zoe Skyforest 13 Comments

Playing chess online is all well and good, and opens up a whole world of competitors that would otherwise be unavailable in one’s local area. But there’s something to be said for playing over the board, which comes up often enough for many players that they refer to it with the acronym OTB. [Carlos] built an automatic chessboard by the name of Phantom, intending to bridge the disparate worlds of chess, from cyberspace to meatspace.

The basic idea is a chessboard that a player can use in the typical way, moving the pieces on the board as normal. The opposing pieces are then moved automatically to reflect an opposing player’s moves as received from an online chess server.

The board outwardly appears normal, with little to suggest anything is amiss. Only the metallic gleam at the base of each piece gives the game away. Pieces are moved by a SCARA arm hidden inside the board, which uses a magnet to drag them around from position to position. It’s quite something to watch the pieces glide around as if by magic, even more so when one is dragged off the board in a combat situation.

As for the control system, an Arduino Nano 33 IoT handles online connectivity to fetch game data from the Lichess chess server, while an ESP32 is responsible for all the motors, and a regular Arduino Nano scans a matrix of Hall effect sensors responsible for locating pieces on the board.

The system allows for seamless play, detecting when pieces are moved by the player via the Hall effect sensors, and reporting back to the chess server online. Similarly, when the game state is updated, the SCARA arm steps in to move the relevant pieces reflecting the moves of the distant player.

It’s a fun project, and one that will surely light up the many chessheads in the Hackaday community. We’ve seen other automated chess builds before too, like Trap Chess, in which pieces can suddenly fall from the board at any time. Video after the break.

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Old Phone Becomes MIDI Controller

June 9, 2021 by Zoe Skyforest 5 Comments

MIDI controllers come in all shapes and sizes. Commercial products based on keyboards or matrixes of buttons are popular, but there’s nothing stopping you from whipping up your own creations out of whatever strikes your fancy. [Kevin] has done just that, turning an old telephone into a working MIDI device.

The phone in question is a Doro X20 wired landline phone. Being surplus to [Kevin’s] requirements left it ripe for the hacking. A Raspberry Pi Pico was wired in to the phone’s keypad, slimmed down with a hacksaw in order to allow it to neatly fit inside the original enclosure. Then it was a simple matter of whipping up some code to read the buttons and output MIDI data via the Pico’s serial output.

Later, [Kevin] brought the design into the modern world, setting it up to talk USB MIDI using the Pico’s onboard USB hardware. This makes using it with a computer a cinch, and lets [Kevin] control a DAW using the handset controller.

It’s a fun build, and one that shows how you can easily build your own MIDI hardware using nothing but a soldering iron, some buttons, and a modern microcontroller. From there, the sky really is the limit. Whether you like big knobs, easy playing, or have your own personal tastes, you can build what you like to suit your own style. When you do, drop us a line! Video after the break.

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Old DSLR Lens Becomes Useful Soldering Magnifier

June 9, 2021 by Zoe Skyforest 10 Comments

Soldering tiny stuff is hard, if not impossible, without some optical assistance. [Ad_w00000] was having just this problem, so built himself a soldering magnifier to help.

The magnifier uses a variety of components [Ad_w00000] had lying around. For the optical side of things, an old Canon DSLR zoom lens was pressed into service as the main magnifying element. The lens was then fitted with an old laptop webcam, which was glued into an old lens extender to avoid modifying the main lens itself. The webcam is hooked up to an Asus Tinkerboard fitted with a touchscreen display to show the images. The whole lens assembly is then fitted onto an old TV stand to enable it to sit far enough above the work surface to focus properly.

The build is a great example of building something useful out of whatever you have on hand. Sometimes, that’s cheaper and quicker than spending money and waiting for something to ship. It also has the bonus that you’ll learn useful skills along the way.

We’ve seen other great soldering hacks recently, too, like this gimbal to help steady hand tremors. If you’ve got your own coming together, be sure to let us know!

Nintendo DS Transformed Into Gameboy Macro

June 8, 2021 by Zoe Skyforest 7 Comments

Nintendo’s Game Boy line were the world’s most popular handheld gaming systems, but did have their drawbacks. Most notably, the Game Boy didn’t receive a backlit color LCD until the Game Boy Advance SP launched in 2003. Of course, you can always build your own Game Boy that rectifies this and other shortcomings, and that’s what [JoshuaGuess] did with this Gameboy Macro build.

The build ends up like a bigger version of the Game Boy Micro, the final release in the Game Boy line.

The build is based around a Nintendo DS Lite, one of Nintendo’s later handhelds featuring dual screens. In this build, the top screen is removed and discarded entirely. The motherboard is then hacked with a resistor on some test points to allow it to still boot with the top missing. The shell of the bottom half is then cleverly modified with epoxy clay and paint in order to hide the original hinge and give a clean finished aesthetic.

The final result is essentially a larger version of the Game Boy Micro, the final handheld in the Game Boy line. It also has the benefit of a bigger, brighter screen compared to virtually any Game Boy ever made. The only thing to note is that the DS hardware can only play Game Boy Advance games, not the earlier 8-bit titles.

It’s a fun build, and one that goes to show you don’t have to throw a Raspberry Pi in everything to have a good time. That can be fun too, though. If you end up building the Game Boy Nano or Game Boy Giga, please let us know. Be sure to include measurements to indicate how it’s scaled in SI units relative to the Game Boy Micro itself.

Electric Vehicles Could Be The Grid Storage Solution We’ve Been Dreaming Of

June 7, 2021 by Zoe Skyforest 157 Comments

As nation states grapple with the spectre of environmental and economic losses due to climate change, we’ve seen an ever greater push towards renewable energy sources to replace heavier polluters like coal and natural gas. One key drawback of these sources has always been their intermittent availability, spurring interest in energy storage technologies that can operate at the grid level.

With the rise in distributed energy generation with options like home solar power, there’s been similar interest in the idea of distributed home battery storage. However, homeowners can be reluctant to make investments in expensive batteries that take years to pay themselves off in energy savings. But what if they had a giant battery already, just sitting outside in the driveway? Could electric vehicles become a useful source of grid power storage? As it turns out, Ford wants to make their electric trucks double as grid storage batteries for your home.

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