[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.
[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.
[bongodrummer] wanted to use a lathe to make some gifts for his family. Instead of buying one, he decided to make one and recycle some parts in the process. More info after the break. Continue reading “How To Build Your Own Lathe”
Pulse Width Modulation is a topic that tends to give a lot of beginners trouble. [Daqq], whose nixie plasma ball we covered a few days ago, has a simple but effective PWM project that you should take a look at. The circuit used 9 LEDs clustered together into 3 sets of RGB modules and connected them to an AVR ATtiny2313 through some current limiting resistors. Most of the time the PWM function of the AVR’s timers would be used to generate the signal but this application calls for 9 signals which is more than can be produced by this chip. The workaround is to generate the signals using software PWM. Continue reading “Software Pulse Width Modulation”
Over at SpriteMods, [sprite_tm] realized that a microcontroller could be used as a boost converter to power itself. A boost converter steps up voltage from a battery by switching the output of a coil. First, it is tied to ground so a magnetic field can build up in the coil. It is then released as a higher voltage than the input. Normally dedicated chips do this at an incredibly high frequency, but the PWM signal from an AVR works well enough. This can be used in low-power situations where space is an issue.
[via EMSL]
[youtube=http://www.youtube.com/watch?v=WnWJki-zwsE]
[Humberto] from NerdKits sends in the newest addition to their excellent collection of videos. This video goes over the basics of DC motor control with microcontrollers. They begin by showing nine experiments and observations that can be done by the average hacker with a multimeter, motor, LED, and jumperwire. Using the results from these they show how to model and calculate the properties of a motor. Lastly, it shows how to control a motor using PWM. They have supplemental text and demonstration code for an ATmega168 on their website.
[Hazard] wanted a full color POV display for his bike wheel. Adafruit’s SpokePOV is single color and Monkeylectric’s original version didn’t display images. He also balked at the cost and decided to manufacture his own version. It uses 16 RGB LEDs on a single layer board he manufactured himself. It’s an entirely through-hole design to make assembly easy. It uses a hall effect sensor to synchronize the image display. The two main components are an ATmega328p microcontroller, which should make it Arduino compatible, and a TLC5940 PWM LED driver. It’s a very well documented build and certainly a good looking effect.
[via adafruit]
