Controlling An AC Drill Using One PWM Connection

August 31, 2010 by Mike Szczys 22 Comments

This peculiar setup allows [Ben Krasnow] to control an alternating current device using one pin on a microcontroller. He’s experimenting with a power drill and has relocated the trigger circuitry that makes it spin. On that board he found a variable resistor combined with a capacitor which control a triac, actuating the speed of a drill. [Ben’s] solution works great and isolates the drill from the control circuitry. He replace the variable resistor with a cadmium sulfide photoresistor (basically a variable resistor whose resistance depends on the intensity of light). Pulse-width modulation is used to adjust the brightness of an LED shining on that photoresistor and thereby affect the speed of the drill. This is such as simple alteration to the drill we’d call it MacGyver-esque.

See a demonstration after the break.

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RGB Lamp Bulb Replacement

August 9, 2010 by Caleb Kraft 14 Comments

[youtube=http://www.youtube.com/watch?v=TwZBMJS1teg]

Wanting to make some unique and interesting gifts for his nieces as well as improve his PCB skills and expand beyond Arduino, [Jay] has made these color changing Ikea lamps. He’s using an ATTiny2313 for the brains, a handful of RGB LEDs plus 3 warm white LEDs to keep the wife happy. you can download the schematic and PCB files if you want to reproduce this one yourself. You can see his PCB making skills have improved since the nursery room temperature monitor. We think his nieces will be pleased with their gifts.

[via HackedGadgets]

Sound Card Driven Servo Motor

May 26, 2010 by Mike Szczys 14 Comments

[youtube=http://www.youtube.com/watch?v=1LG2Ecsk13Q]

[Darrell] is using a sound card to drive this servo motor. The motor draws power from a cellphone battery with the control signal coming from one of the audio channels. It’s not too surprising that this works since the motor just needs a PWM signal to operate and that’s what is used to create the different frequencies of sound on electronic speakers. We’re not sure what [Darrell’s] got planned for this system but he mentions that two servos can be used, one on each audio channel. If you’re not using your sound card this would be a way to stop using the Arduino for that mail checker and just use a little flag attached to a servo. When mail comes in the appropriately engineered sound raises the flag.

USB VU-meter

April 22, 2010 by Jakob Griffith 14 Comments

[youtube http://www.youtube.com/watch?v=jsg24MGNpRc&feature=player_embedded%5D

WaitingForFriday’s [Simon Inns] is quite possibly the USB interface and PIC master. This week he let us know about his VU-meter repurposed as a computer performance monitor using a PIC18F2550 and his open source USB Generic HID communication class. With PWM the meter’s needles and RGB LED can be accurately set and even dampened for CPU usage, network usage, HDD utilization, and even memory usage. Oddly enough, in his software we didn’t find the ability to use the device as a VU-meter – go figure.

PWM Fan Controller For External Hard Drive

April 14, 2010 by Caleb Kraft 27 Comments

[Alan] noticed that his external hard drive was getting quite hot to the touch after a few hours. He says that it was probably designed to handle the heat sufficiently, he thought it would be fun to beef it up. He’s using a pic 12f675 microcontroller as the brain and an LM35 temperature sensor. The Fan speed is varried in 8 steps from 35 degrees C to 45 degrees C.

Autonomous Bassline Generator

December 18, 2009 by Mike Szczys 16 Comments

[youtube=http://www.youtube.com/watch?v=dcqpxd0O6Mw]

We’ve been watching this project ever since [Dann] emailed us about the first prototype back in September. This bassline generator has a lot of functions we like, such as an adjustable melody seed, light-sensitive controls, and device interactivity. Line up a row of them and they’ll sync up the beat, building layers of sound on top of each other (see the first video after the break).

The system is built around an ATtiny84, putting its pulse width modulation channels to work for sound generation. [Dann] has some kits available but he’s also posted everything – the schematics, PCB layout, and code – if you want to throw one together on a breadboard.

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