NodeMCU dead after dimming lights

Hello. I’m not sure if this is the right place tonpost this as it’s more of a circuit problem. Last week I made a circuit that can change a RGB led strips colors using the blynk app. It worked well until this morning, when I noticed the led strip was turned on, on a random color(i turn it off at night). For this montage, I used a NodeMCU With Esp8266 and 3 mofset tip120 transistors, each used for dimming one of the three colors. The led strip is powered by a 24v power source and the nodemcu was powered by a 5v. The nodemcu won’t work anymore, when I connect it to the circuit the led strip just turns on yellow. When I connect it to the pc it does make the sound of a new device cinnected, but whenever I try to upload the code it says “espcomm_upload_failed”. Also I cant seem to reset the board, the built in LEDs dont turn on amymore, only the red one, but very weakly. I’ll post a photo of the circuit below. I am aware that I probably won’t be able ti use this biard again, but I’d like to know if there’s anything I can do so this won’t happen again. Thank you image

tip120 isn’t a mosfet , but a Darlington !
I think you have one the three Tip120 dead, so you should have 24v on one of the pin of your nodemcu. :wink:
IMHO , nodemcu is dead.

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The transstors are fine. I added 5k resistors between the base of the transistor and the pins of the board and it seems that the board doesn’t heat up that much anymore. Guess I’ll just have to wait and see

maybe reverse current? :scream:
resistor isn’t enough.
you need a diode too.
but in any case, always use mosfet !

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Its better to use a Opto isolator to turn on/off the transistor instead of connecting it directly to base.
Try changing the TIP120 with MOSFET IRLZ44N. This can be directly driven with the nodemcu.
But its always recommended to use a MOSFET driver to drive the MOSFET’s.
There are lots of circuits on google. Try googling !!

All the best.

Thank you both for your help. I have ordered a few mofsets online, but until they arrive would you recommend keeping the circuit running? As I stated before the nodemcu doesn’t heat up anymore. The one before it was burning hot, couldn’t touch it. I also think that it might’ve been a faulty board, as it couldn’t work properly for the first time. If I ever unplugged it from the power source I would have had to reset it multiple times before it would finally show the correct colors.

also what way should the diode be? With the anode starting from the board and the cathode going to the base of the transistor, right?

to avoid reverse current.
you can also add a 3.3 v zener between resistor and mcu.
but the best is using mosfet transistors…

I only have a few 1N4007 diodes. Would they be alright temporarily? Also the anode should be connected to the board pin, and the cathode to resistor/base of transistor, right?

That’s right.
But if I were you, I’ll use MOSFET.

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Diode’s has a forward voltage drop. So check the data sheet. If the nodemcu is spitting out signal between 0-3.3v then you can measure only 0-2.1/2.7v (approx.) . So this will effect your brightness or color temperature that you desire. Its better you go for

And you may also need to a mosfet driver with an inductor to suppress the high switching frequency noise…

@Madhukesh I did order some online, the diodes will just have to do until they arrive.

And you may also need to a mosfet driver with an inductor to suppress the high switching frequency noise…

So that’s what I am hearing when combining colors