Another Stir Plate

[motleybrew]

In the spirit of a restless brewer, I've been stepping up my processes; and the next step was better pitch rates.

This stir plate is made of 99.99% salvaged parts. The only purchased component was the 555 chip used for the PWM circuit. Everything else came from a dead computer, a curbside home stereo receiver, and the box is an old gift box for teas.

The main control is a PWM circuit powered by a 555 timer chip. Pulse width is controlled via the 500k (or 50k, can't remember) pot. I used a hard drive magnet and glued it to an 80mm case fan.

Total cost was $2 for the 555 chip.

Breakdown of the internals:
1)AC mains comes in and is fused with a 1A inline Buss fuse.
2)A step down transformer takes 120V to 18V.http://afrotechmods.com/tutorials/2011/11/28/electrical-transformer-tutorial/
3)A bridge rectifier converts to DC.http://afrotechmods.com/tutorials/2011/11/28/diode-tutorial-and-ac-to-dc-conversion/
4)A linear voltage regulator holds V at 12V.http://afrotechmods.com/tutorials/2011/11/28/voltage-regulator-tutorial-and-usb-charger-circuit/
5)The PWM circuit http://afrotechmods.com/tutorials/2011/11/28/pulse-width-modulation-pwm-tutorial/

Questions?

[ame="http://youtu.be/aNxSRedAEZ0"]http://youtu.be/aNxSRedAEZ0[/ame]

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[mtnagel]

Looks awesome. Good job!