I'm trying to create an accessory controller for my 2001 BMW motorcycle. To those who aren't familiar with the older BMWs, there is a separate "turn signal cancel switch" on the handle bars that when pressed, grounds an input on the flasher relay and stops the lights from flashing.

I would like to use this ground signal as a trigger to turn on/off some auxiliary lights. .

I want to make it so that:

  1. You hold down the turn signal cancel button for 3-5 seconds to turn on the aux lights.
  2. You tap the turn signal cancel button to turn the lights off.

I've looked at some examples using a 555 chip LIKE THIS however this example uses a constant trigger voltage source. I would like to keep the footprint a small as possible. Ideally, I would like the footprint of the entire circuit to be the size of a typical automobile relay.

There is an aftermarket controller already available that does this however I have additional ideas that will incorporate this controller into a fuse block/accessory all-in-one to keep the footprint small. Plus I want to LEARN!

Any help you can provide will be greatly appreciated! Thanks in advance!

  • \$\begingroup\$ A microcontroller is typically used for this. You should add the relevant wiring schematic for that switch and relay, your explanation is confusing me. 2 wheels down ;) \$\endgroup\$ – Passerby Sep 13 '18 at 16:22
  • \$\begingroup\$ The "turn signal cancel switch" is just a momentary push button that goes to ground. I could give you a schematic but it would look exactly like what you think a momentary switch looks like. Same for the relay. I suppose I could use a small microcontroller but I wanted the design to be as simple/reliable as possible. \$\endgroup\$ – ryanhettenbach Sep 13 '18 at 16:39
  • \$\begingroup\$ You can make things pretty small by using surface mount components. \$\endgroup\$ – τεκ Sep 13 '18 at 20:19

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