Mar 13

Yet another drill on my workbench

How many drills do I really need? Well, one more would not hurt, I guess. I have got dead 9.6 volt Black and Decker with dead battery from my neighbor on a garage sale last year. My idea was to hook it up to 12 volts from PC power supply.

I knew that small wall outlet – style power supplies would not work – see my learning curve.

I have two old PC power supplies to play with. They both shut down as soon as I hooked up the motor. Oh well. I was about to give up, but then I decided to try 5 volts. Surprisingly, even though motor does not spin very fast at this speed (fast enough to drill, but not fast-like-crazy), it has a lot of torque. I cannot stop the spindle with my hand. What is good – it is high quality high precision drill. I was able to drill a hole across the yard wooden ruler (I have a broken one to play with), and the ruler is thinner than USB connector, and one inch wide, and the drill bit came out right in the middle.

Anyways, here is the drill:

P.S. Do you think connecting the drill to wires +5 and +12 to get 7 volts is a good idea? Well, may be in theory. It does not work, power supply just turns off (I have a lot of respect to whoever designed protection circuit for PC power supplies – it works great)!

Dec 11

High speed photography

Lyosha Kojenov was excited about high-speed photography. He has all the photo-setup, but has no equipment to trigger a flash at the right moment. I do not have all the photo set-up, but I have Arduino. We decided to combine efforts.

The idea is simple – something happen that makes noise – microphone catches it, amplifier amplifies it, rectifier rectifies it, Arduino measures it with ADC, add some delay and trigger a flash.

Studio shall be dark, camera shutter shall be open. That’s pretty much it.

First, I made audio amplifier on a breadboard.

Continue reading