Bob Could Stop On A Dime

October 25, 2004

Unfortuneately, others could not. Tired of rear-end repairs, Bob designed an automatic flasher that uses a pressure sensor in the brake line to measure the pressure applied to the brake pedal. The sensor output controls the rate of a 555 multivibrator chip, which in turn drives a high-power MOSFET in series with the brake lights. The harder Bob brakes, the faster his brake lights flash, and hopefully the harder the people behind him brake.

Brake Warning System Parts List
Amt Part Description Allied Part #
2 NE555 Timer 248-0294
1 Capacitor .001 muF 852-1145
1 Capacitor 10 muF 852-5683
1 Capacitor 1 muF 852-5677
2 Resistors 221 KU 296-0024
3 Resistors 100 KU 296-0011
1 Resistor 100 U 296-0007
1 Resistor 332 U 206-0031
1 Transistor NPN 431-0408
1 Transistor IRF5210 273-0279
1 Toggle switch 642-1148
1 Red LED 749-0700
Additional parts required: transport vehicle with brake lights

For Bob Walter's complete instructions on how to build a brake warning system, go to

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