MotoMonster + Arduino wind - burned Arduino

Hi,

I have trouble with power supply and MotoMonster. I'm trying to build wind using SeaFlo blowers, Arduino and MotoMonster.

I connected everything normally - MotoMonster on Arduino as shield. For first tests, I used PC power supply and connected it to Molex +12 V branch and ground. It worked perfectly.

Then I got this 12 V power supply designed for LED usage and connected it like this.



But once I connected it to MotoMonster, exactly as before I smelled something burning so I plugged it of instantly, but the Arduino was burned - nothing cannot be uploaded anymore and power LED is off, but it's still recognized by PC so it's not burned completely.

Also with this power supply when turned on, one of the MotoMonster chips gets very hot instantly, but over time this heat lowers a bit. This doesn't happen with PC power supply at all and chips are only mildly warm.

I thought I did something wrong and tested it again later with another Arduino, but it burned exactly the same way.

What could cause it to burn with this LED power supply, but work ok with PC power supply?

I have done some more testing on the burned Arduino - it still works, the program is still there so when blower is connected it turns on. I have measured it with multimeter and both power supplies give 12 V as they should.

I also measured all the pins going to Arduino and there is major difference between those two power supplies.

With LED power supply, most of the pins has 12 V or more on them, so it seems the power from power supply is leaking through to Arduino through all the pins which caused it to burn.

If I use PC power supply and connect it to Molex +12 V branch, the pins going to Arduino have correct voltage, for example on +5V pin is really around 5V on +3,3 V pin is really around 3,3 V.

I can do more testing on this fried Arduino as I'm too scared to try it on new one before I figure out what might be wrong.

Anybody has idea what's going on? Why one power supply does something so different, but both of them has steady +12 V voltage? Unfortunately I have only 10 Amps maximum on multimeter so I'm afraid to measure power draw.

Am I doing something wrong or the LED power supply is faulty? Or perhaps LED power supply shouldn't be used at all? It was quite cheap and possibly from China. Should I try to buy some more expensive brand like MeanWell, for example this SP-240?

This was my first time soldering pins to MotoMonster, but it looks nice and it works with PC power supply so I guess problem shouldn't be there. Really cannot think anything else beside faulty LED power supply...

Many thanks for any help!

Oh no I hate when this happens - especially when the cause is unknown! We fried a couple of Arduinos this year that were running the electric shifting system on our formula car.

One random tip that probably won't help you but stumped us for a few minutes is to make sure not to test the Arduino on a metal table (duh!) - this gave really odd results with all the pins that were shorting hahah.

I'm not sure that I completely understand your setup/issue but it sounds like it is likely an issue of too much power through something. Here are some random tips:

• Most Arduinos are either 3V or 5V tolerant - make sure you are only passing what it can handle - this includes control/logic signals, sensors, communication, etc. For example I used to use 5V sensors on a 3V board and had to use a voltage divider to get the logic output to the correct level.
• Try Googling "Arduino hardware test points". I don't know any results that are particularly good but this can help you narrow down what got fried on the Arduino which can help determine the cause. Most test points should be testable with a basic multimeter (similar to the tests you have run) but some might require an oscilloscope.

Unfortunately, testing the power supply thoroughly would require the use of a high quality bench-DMM or similar equipment which can be hard to come by.

Best of luck! Hopefully you won't have too many more Arduinos burn on you

Hey, I finally managed to get new power supply, I went for MeanWell and it doesn't burn Arduinos anymore

Unfortunately I think the former power supply damaged MM and it works only with one blower now. I had another one just for reason like this, however the second MM is probably faulty from manufacturing - it also works only with blower, in this case the other one. It feels I'm a bit unlucky with this project so far But I ordered another MM, unfortunately it will take like 3 - 4 weeks to get here from China, I hope this one will work

Strange thing is that the faulty MM works ok if I change direction in code to counterclockwise.

I played with it for couple of hours and came to conclusion it must be faulty MM, I don't know anymore