- on Home & Garden
- Published in issue 9/2012 on page 40
The principle is a very simple one: once the bike has been set on its stand, three carefully-positioned mercury switches give position information to a microcontroller, which it then memorizes when it is powered up. The surveillance starts right away; any change in the bike’s position will upset the configuration of the three switches and set off the alarm.
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R1 = 22kOhm
R2 = 1kOhm
C1,C2 = 10µF 16V, radial
D1 = 1N4148
T1 = BC547C
IC1 = ATTINY13-20PU (Atmel, DIP-8, Elektor # 120106-41)
IC2 = 78L05
S1,S2,S3 = tilt switch, 90 degrees, e.g. RBS040200