I would like to control my outdoor LED floodlights with a Raspberry Pi (it has 3.3V outputs) and/or an Intel Edison (it has 1.8V outputs).

I opened up one floodlight and found it had a LED driver and the LED module itself had a 30V forward voltage. I’ve attached what I think is the driver’s circuit diagram. (The chip has a control input, but the electronics are potted, so I don't have access to it. If it was there my problem would be solved...)

There are a few ways I could do this:

- Leave the flood light as-is and put an AC relay circuit on the Pi. Boring. And doesn't let me dim the LEDs.
- Separate the driver from the LED and put a DC switch (power FET) in series. The problem with this is that the driver does not isolate the AC input from the output, so I would need an isolator, but this could work.
- Buy a new driver that isolates input from output, ground one side of the output and use a FET as before. My question here is what effect does disconnecting and connecting the LED load with the FET have on the driver? Will the driver increase the output voltage in an attempt to keep the current constant? How high could it go? The FET will need to deal with the higher voltage, if this is the case.
- Buy a new driver with a dimmer control input - isolate the dimmer input with an opto-coupler if it isn't already isolated. This is probably the best choice, but they are pretty expensive.

Is there a better way to do this that I haven’t thought of? And does anyone know of a source of inexpensive drivers, with a control input?

 

Welcome to AAC.

First read the Tos before posting any diagram using live voltages

 

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