Hidden automotive kill switch

316

03:05:32

07/24/2021: Initial design

2 555 timers, a reed switch and a 12V automotive relay are the major components of this kill switch. The switch is a reed switch hidden under the dash, activated by a small magnet in a key FOB. LED #1 lights for about 2 seconds. This LED indicates successful circuit activation and is mounted somewhere easily viewable by the user. LED #2 lights for about 25 seconds. This LED is for test only and indicates ignition line active.
This resistor and LED pair are not part of the installed circuit. In the install case the 12V automotive relay activation completes the ignition wire circuit from the ignition switch for about 25-30 seconds, more than enough time to start your car. After that the circuit deactivates and the car can not be started until the magnetic fob is used to reactivate the circuit again. Unless you have a magnet and know where the switch is located under the dash the car is impossible to start.

07/25/2021: Updated to real world R/C values for breadboarding.

published 4 years ago

wyoelk

4 years ago

Real cool circuit! Have used couple logic gates with rc tanks but two 555s look simpler and with a potentiometer could easily change time delays. Again, nice circuit

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