ardurino board getting hot?

coralbeauties · Feb 7, 2016

I am working on setting up a used lighting system that I got that is run with a ardurino controller. I power the controller up with nothing hooked up to it and the back of the board is getting really hot. Hot enough I cant leave my finger on it. The hot area is close to where the power cord plugs in the board. Should I be concerned?
thanks
Jeff

Ann_A · Feb 7, 2016

Exactly where on the board is it getting hot? If you hold the board with the front facing you and the power jack down, where in relation to the jack is it getting hot? If you power it off of USB does it still get hot? Also, I'm assuming you have the Arduino Uno, is that right?

coralbeauties · Feb 7, 2016

This is a mega 2560 board running the jarduino program. It has a 9v power supply and the part that is getting hot is a little black chip just left of the power jack. I had the controller in test mode and it wasnt getting hot and as soon as I turned it into the normal timer/cycle mode it got hot right away. I dont have anything plugged into it other then the power supply jack right now. Do you know if I can power fans directly from this controller or do I need to have fans that have pwm signals to turn them on with. I am trying to simplify things. Right now I have the fans controlled by a wall timer with a 12v power jack, would be nice to get rid of that mess.
thanks
jeff

Ann_A · Feb 7, 2016

Is the back of the board getting hot or is it the chip on the front?

As far as the fans go, the board only supports 5v signals. It also doesn't have a large current rating per pin. I would suggest using relays to trigger the fans. You can build a simple relay setup that will switch the power to the fans on and off. The fans will require their own power supply though. I would also not suggest using pwm to control the fans. If it's simply on or off that you need, I would use a regular digital output pin. If you want to control the speed of the fans then you would need pwm.

TheEngineer · Feb 7, 2016

That's likely the voltage regulator heating up. Three pins on one side and one fat pin on the other? That board runs on 5V so the regulator burns off the excess voltage. It shouldn't be getting incredibly hot though. Is anything hooked up to the board or is this just the board running unconnected to anything? Is a sketch running?

coralbeauties · Feb 7, 2016

It is the regulator that icecool2 described. I should probably pick up a 5v power supply. No there is nothing hooked up to the arduino. The jarduino program has a screen for slidder adjustment for testing. while in this screen with all the setting set at zero the regulator will not heat up. If I switch over to the normal function screen and the controller tries to turn on the drivers for that time of the day the regulator will get hot fast.
thanks
Jeff

TheEngineer · Feb 8, 2016

Don't get a 5V power supply unless you plan on wiring directly to the board. The voltage regulator needs a voltage drop to function. That said, if the regulator only gets hot when you run certain programs, it is operating properly. You could get a 7V power supply and it would be a little better.