I have one of these led projectors which is normally powered by the embedded motion sensor.

I want to be able to power it manually by a switch button. I need to do this in both alternative and concurrent mode. By alternative I mean that the projector is turned on either by the motion sensor or manually by myself; by concurrent I mean that it is turned on by both at the same time.

In order to achieve this I can follow two these strategies:

  1. simulate a motion detection by providing the control circuit with the same signal provided by the motion sensor;
  2. power the projector directly.

I have opened the device and have found out the following:

  • the projector is powered by a 22-25VDC power supply provided by the control circuit.
  • out of the motion sensor come out three wires which are fed into the control circuit. I have yet to investigate what do each of this does.

In both cases the difficulty I have is protecting the existing circuit from voltages and currents generated by the power I supply myself. I think this could easily happen in the concurrent mode.

How do I deal with these two inputs?

  • \$\begingroup\$ I made a few minor edits to help with formatting and an error for your description of what alternative and concurrent modes were. Please review them and make sure it remains what you intended it to mean. Also I think you have misunderstood what the motion sensor does. It is merely an activation signal, not a "power" input. \$\endgroup\$ – KyranF Oct 21 '14 at 18:22
  • \$\begingroup\$ Is this LED light in some kind of custom product? The item you have shown a link to is just an LED which uses mains AC Voltage (85 - 250VAC). Please show us pictures of the thing you have pulled apart, and describe more about what it is. Your actual question of protecting existing circuits from your own input power is not actually your real issue - you want to make a custom control interface which has a two modes of operation, and what you REALLY need to work out is how to turn on the product maybe by using it's motion sensor input (your best chance) \$\endgroup\$ – KyranF Oct 21 '14 at 18:29
  • \$\begingroup\$ @KyranF Ok I will take pictures and post them tomorrow. \$\endgroup\$ – geraldCelente Oct 21 '14 at 18:31

By fiddling around with the device I found out the projectors are turned on when power is first supplied to them. Therefore a switch relay did the trick.

A big thank you to the community for your support!

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  • \$\begingroup\$ Forgive me for my naivety, what is the down vote for? \$\endgroup\$ – geraldCelente Nov 1 '14 at 21:12

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