[Kizo] built an extraordinary persistence of vision clock. The design uses a PC cooling fan to spin the propeller-like PCB. As it goes around, a hall effect sensor synchronizes the illumination of the LEDs to draw the display. Power for the rotating electronics is transferred wirelessly via a transformer on the base and coil on the spinning board. The final version uses an ATmega324 microcontroller running at 20 MHz and has an IR receiver for changing the settings. The 3000 lines of code bring a lot of bells and whistles, including a menu system with a huge amount of settings from tweaking the clock display, to font selection for scrolling messages. Take a look at the demo after the break. The double-sided board looks like it’s pretty difficult to etch at home, but as you can see from the forum post (translated), [Kizo] did a great job on this build from start to finish. Continue reading “Spinning POV clock done oh-so-right”
[Tyler LaVite] tipped us off about the generator he built. He combined a 5.5 horsepower Honda motor with a 10 horsepower electric bandsaw motor. To get an induction generator to produce alternating current you must feed electricity into the system to start the magnetic flux. [Tyler’s] solution was to include a bank of capacitors totaling 230mF which charge from the motor, then release back into the system. It’s not as green as the syngas generators we’ve seen since it still uses fossil fuel, but it reuses old parts sending less to the landfill.
[Tim] let us know about a video outlining some covert camera devices the Air Force is developing. The video takes a lot of time to explain induction to those who’ve never heard of it but we liked to see the bird-like concept animations. They’ve already developed cameras that will clamp on to power lines in order to use induction as a power source. Shown in the video is an eight-rotor quadcopter they’re hoping to use to deliver the camera covertly. But the animations show a winged robot similar to a hawk that has a camera for a head. Having seen some of the other flying devices in development this may not actually be that far off.
[Tim Williams] likes to heat things up with this induction heater he built. At peak it can use 1000W and as you can see in the video, that’s more than enough power to heat, burn, and melt a plethora of different objects. The case design uses a center divider to isolate switching noise from the magnetic field with the whole unit housed in aluminum because it won’t heat up from stray magnetic fields. He’s selling plans and kits in case you want one, but we just don’t know what we’d use it for.
Continue reading “1000W induction heater”
[Robotkid249] details how to build a wireless power transmission system. This is similar to the commercial applications we have seen in a TED talk as well is in a Sony prototype. Power is fed to a ring made of magnet wire. A smaller loop is attached to the system that you want to power and picked up from the base unit. In this case, he is powering some LEDs but the concept can be tailored for your purposes such as an inductive charging pad. We’d like to see a hack that incorporates the base into a mouse pad (or the desk itself) and the receiver into the body of a wireless mouse. We’ve seen a commercial solution along these lines but we want one that doesn’t require a physical connection for power transfer.