Hey yall, I extracted the LED and driver from a car headlight, and want to mount it to my drone. My question is: Would either of these be a good way to power the headlight/What do I need to change?
Headlight: 12v 55W
Schematics:
NPN MOSFET, you mean N-chan?
RPI 5 V, I thought all Raspberries are 3.3 V
That optocoupler needs to be powered, it can't drive the Gate on its own.
Neither of those methods will work as diagrammed.
Optocoupled relay modules are available that will accept control input from 3.3V processors like the RPi. Keep the 12V lamp supply completely separate from the MCU (with a relay, the various power supply grounds need not be connected).
Yes, sorry I meant N channel
Regarding the 3.3v, i think you are right, so I wouldn’t use a resistor
I need them connected, as the 12v LiPo is going to be powering the Rpi (through a buck converter), but their ground is shared
I was confused by the design and see now that you do drive the optocoupler +12 V.
Your diagram could use some improvements 
As of now it looks like a 12 V and 5 V battery back to back.
+1
Diagram looks like Chinese writing to an EE.
Convention is:
Signal from left to right.
Supply up, grounds down.
Leo..
I'm just wondering if the drone can lift the battery and headlight. It seems like a battery for a headlight would be big & heavy.
But an LED headlight bulb probably isn't really 55W so maybe the battery doesn't have to be as big as I think. 55W is about right for a regular-old low-beam bulb. Or maybe it doesn't have to be on for long.
+1
A LED light seems more suitable for a drone than a 55W incandescent bulb, which produces mostly heat. A 10W LED should give about the same amount of light.
Leo..
I have GE Basics 60W LED bulbs that consume 9W 60HzAC.
Is it possible that the power circuit can run on DC?
For 9W power, that's a lot of bright light!
Correct. The light efficiency ratio of incandescent vs. LED is about 7:1.
Ac single 18650 cell is about 10W/h.
Leo..
Maybe see about a cheap inverter, good for 20~30W.
Well the headlight has been stripped down to just the led with its enclosure. It weighs only a few grams. The battery to power it is the same battery to power the drone, so that isn’t the issue.
I pretty much just need a schematic for switching power to the LED from my 12v battery using one of the raspberry pi digital pins
I do have the driver with it. Is this the schematic you recommend?
Yes but be aware that the control signal (PIn) is inverted. A LOW will turn the LED ON, a HIGH turns it OFF.
Actually you could increase the 1K resistor to 5.1K to save a little battery power.
Alright, I appreciate it!
Always do!
- Sorry, this was directed to the OP