Here is an way of making a simple electrical motor, to see more interesting videos have a look at the collection that David Colarusso has put together.

uC Hobby has a nice article about a project that uses an Arduino Microcontroller to read in temperature data and control an optically coupled motor using PWM.

“Oscar Gonzalez gives us a simple tutorial for speed controlling a PC FAN and reading a LM35 temperature sensor with an Arduino microcontroller. He covers the use of an optocoupler, PWM (Pulse Width Modulation) and reading analog voltages with the Arduino. This devices is very simple. It consist of an phototransistor and a LED inside the same package. The phototransistor turns on or conducts current when the internal LED lights. The brighter the internal LED the more current can pass through the phototransistor. The LED and phototransistor are physically isolated from each other. This physical isolation protects the input side (the LED) from voltage spikes on the output side (phototransistor) and can provide the voltage translation needed for this project. When the LED is activated from the 5V Arduino the phototransistor will turn on and pass current for the 12VDC fan. The isolation provided by the optocoupler keeps the Arduino is safe from destruction.

The optocoupler’s internal transistor does not have sufficient current capacities to drive a DC motor (like our FAN) directly. To boost the current I used a BD137 transistor which can drive up to 1.5 Amperes. This power transistor is sufficient for controlling PC Fan motors. The PC Fan model I used runs needs about 300 mA.”

Hack your old UPS and install a covert hard drive by using the existing USB connector for access. No one can tell that there is storage in there.

“Your computer downloads in plain sight. Pictures, movies, music, files, whatever! Nobody will even know it’s there. Not your kids, your wife, a burglar – not even the RIAA!”

Via: Hack n Mod

I can just imagine how much fun Andrew Hundt, Boris Lipchin and Ned Fox from Carnegie Mellon University had creating this Wiimote Lego Tank Surveillance Robot.

“This robot is composed of Legos and uses a handyboard as the control hardware. It has 4 wheel drive each controlled by a lego motor, and a pan tilt mount for directing light and the video camera. The Wii Remote talks to a MacBook Pro over bluetooth to modified DarwiinRemote software, and the computer in turn communicates with the robot over a serial port. This robot was designed for and used in a small scale demonstration of Urban Search and Rescue (USAR) as an assignment in Intro to Robotics at Carnegie Mellon University. Designed, built, and programmed by Andrew Hundt, Boris Lipchin, and Ned Fox at CMU.”

Lush Projects has an cool tape deck hack that allows for some neat sound mods.

“First mod was to setup one deck to allow scratching. To do this I originally removed the pinch roller so that the tape could run free. Later on I realised I could modify the pause button to retract the pinch roller without actually pausing the player.

The second mod was to make a tape delay out of the two decks. The key point here was making a double cassette which allows one tape to be looped through both mechanisms. I then reversed the decks so that the machine recorded one one deck and then played back on the other a moment later.”

Have a look at this huge Seven Segment Display made by Turd, a Hacked Gadgets Forum member. Other than the ones made by the guys as Sparkfun this has got to be the largest one I have seen.

Watch a video of it in action.

“I made this for a test. It’s made from a picture frame, some foam from a camping mat, blue translucent film and a shopping bag all from A Buck Or Two. The LEDs I got out of a crappy flashlight. “

These are probably some of the most expensive clocks around. I would love to have a Robot Arm Clock in my living room though.

“The robot arm is probably the most mathematically complex robot you could ever build. As such, this tutorial cant tell you everything you need to know. Instead, I will take shortcuts and just talk about the bear minimum you need to know to build an effective robot arm. Please bear with the math . . . enjoy!

To get you started, here is a video of a robot arm assignment I had when I took Robotic Manipulation back in college. My group programmed it to type the current time into the keyboard . . . (lesson learned, dont crash robot arms into your keyboard at full speed while testing) ”