No, that sounds destructively wrong.nextguy wrote: ↑Mon Sep 09, 2019 1:29 amIf so, I think I would need to use four of these MOSFETs each one connected to a light strip. The source pin of each MOSFET would go to the Pi Ground pin, the drain pin would go to a GPIO, and then the gate pin would go to the 12v power source. Does this sound about right?
I did the search that you recommended and actually the first result is where I had gotten my setup idea:davidcoton wrote: ↑Mon Sep 09, 2019 9:20 am
No, that sounds destructively wrong.
Put "Pi driving LED strip" in your favourite search engine, read two or three results, and ask again if you still don't understand (no shame in that).
Don't rely on any one website because there is some wrong information out there ... if you tell us what you find, someone will look over it for you and check.
Oh boy yeah you are right... I am still learning a lot about reading schematics and had no practical knowledge with circuits before the last two weeks.Burngate wrote: ↑Mon Sep 09, 2019 10:26 amNot quite!
He has (red, green, & blue) wires connecting the GPIOs to the gates.
His black wires connect the GND of the Pi, the sources of the FETs and the negative of the external power source.
The drains of the FETs go to the LED strip negatives, with their positives connected to external power source positive.
So for each LED strip you have a loop: power souce positive through LED strip (+ to -) through FET (drain to source) and back to power source negative
AND you have another loop controlling the first: Pi GPIO through FET (gate to source) and back to Pi GND
Ok thank you. I am having a tough time finding the IRLZ34N in Canada. The amplifier is more readily available so I was hoping I could use that. With the MOSFET, those that I have found seem to have trouble opening at 3.3v. I will keep searching.davidcoton wrote: ↑Mon Sep 09, 2019 3:05 pmFor a short length, the MOSFET is more appropriate. You don't need the power handling capability of that amplifier.
And you must match your supply voltage to what the strip requires. Yours is a 12V strip, it will not work well from the Pi's 5V supply. You should calculate the maximum current required, but I don't think this will cause any problem.
Note: This strip can only be cut at 3-LED intervals, so you need to make each section 12 LEDs long, not 11.
I found an amplifier with 4 channels like this one:
You need to check whether the amplifier will work from the Pi's 3V3 GPIO, or whether it needs a 12V signal (it is intended to work from the end of one LED strip, to drive another).nextguy wrote: ↑Mon Sep 09, 2019 5:44 pmI found an amplifier with 4 channels like this one:
https://www.amazon.ca/gp/product/B07F78 ... 9V8W2LW1AN
It is very cheap also at 9.26 Canadian Dollars. I believe I should be able to drive all 4 light strips with this one amplifier right? Each light strip would plug into 1 channel of the amplifier. So it looks like a very simple solution instead of purchasing and wiring 4 individual FET's.
Start by working out the current requirement for the four LED strips, all on, for both 5V and 12V LED strip.nextguy wrote: ↑Mon Sep 09, 2019 5:44 pmThe other thing I am not sure about is according to the original article I read:
https://www.instructables.com/id/Easies ... pberry-Pi/
I can't figure out if I actually need to plug in an external 12V 2A power supply to the amplifier. I looked around and found that I have lying around both a 12V and 5V LED single color light strip that I could use for this project.