Vibration Sensing Circuit

The LED flickers, the Calvary is on the way. You signal your comrades to get ready. Hoof beats grow louder, the bugler sounds CHARGE.........and ACTION! Analogue VOM meter is our miniature generator using needle vibration to move coil wire in permanent magnet field as input to LM339 amplifier. Any unused LM339 pin should be tied to ground. Meter may need to be turned on side to be most sensitive to up and down motion of table or brick and needle setting off zero to give better swing movement. Meter sensitivity makes a difference as 0 to 50 uA is more sensitive than 0 to 1 mA. Power supply can be 9 to12 volt range.

published 10 years ago