Keep frying my board, not sure why.

Let me just start by saying I'm a novice when it comes to the Arduino.

I'm trying to control a 24v strand of WS2811 LED lights with the UNO R3 using this 24v power supply for supplemental power

I'm following this diagram with an optional 470 resister on the data line. Diagram

My problem occurs when I try to power the UNO and use the supplemental power, the board fries itself. I've now fried two boards and would really like to not fry a 3rd.

Maybe as a helpful side note the lights do light up but don't do any of the programed effects before the board fries itself.

So you plug 24V into the plug located at the top left of your image, which would put 24V into the Arduino Uno 5V pin and into the LED strips 5V pin, and you are not sure why the Uno makes smoke, right?

DON’T put 24V into your Arduino - you WILL kill it.

Get a cheap mobile charger & use a USB lead, remember to connect the 24V GND to the Arduino GND.

And the LED strip, at least the first LED, is most likely fried as well.

I understand that in the diagram picture it shows a 5v LED strip but the one I'm using is 24v.

So if I'm understanding correctly my error was connecting the red positive wire to the Arduino? I do have a 9v power supply I was going to use to power the Arduino itself.

The Arduino is a 5V device.

The input jack can take 12 to 7.5V.

You can power the Arduino with a 9V wallwart plugged into the input jack.


If that was my only issue then thank you for clearing things up.

I do not know if that is your only issue.

You can power the Arduino from the barrel jack or the Vin pin within a recommended range of 7-12V, where it goes through the on-board 5V voltage regulator.

If you have a 5V power supply you can supply power to the 5V pin. The 5V pin goes directly to the chips so if you apply more than 5V you can fry it!

Or, it can be USB powered (5V).

You'll need the USB connection to upload your program anyway so you can start with that and then switch to different power supply later when you're ready to run it stand-alone without the computer connected.

The LED strip can have a separate power supply (in fact it MUST be a separate power supply unless you add an external voltage regulator that can handle 24V in). But, you need common grounds.... The LED needs a ground connection to the power supply and a ground connection to the Arduino.

I've now fried two boards and would really like to not fry a 3rd.

Besides over-voltage, another common way to kill an Arduino is with a static discharge and the best way to prevent that is to wear a ground strap whenever you touch the board/electronics. ....That's actually "over voltage" too. Where I work we are required to use ground straps (and we have to test them every day) but we have foot-straps and grounded floors. I have ESD shoes but I still have to test them every day.

BTW - I think Adafruit has the best WS2811/2812 technical reference, and they have a software library and code examples. (As far as I know they don't sell the 24V version, but it's basically the same except the LEDs are controlled/addressed in groups of 6 so the voltage can be efficiently divided-down.)

Connected 24 VDC to a 5VDC unit (e.g., UNO) will fry the UNO. No doubt about that. Consider what would happen if you connected 120volt (but DC) to your car battery.

So, add a 5VDC coil relay to your control circuit. Connect the 24-volt power for the LED string to the switching contacts on the relay. The relay will handle the power for the LED strings without any of that energy running through the UNO.

Make sure that the switching contacts on the relay can current load of the LED String.

Tom Kane , Vancouver, BC, Canada

ADDED NOTE: DVDdoug makes an important note. The ground wires for the two power systems (24 Volt power and 5 Volt power) and the ground for the LED-strip must be connected together.