I have a simple string of LEDs hooked up to an arduino uno. Every now and then my arduino gets fried and the chip is gone (gets really really hot and then stops working). Seems strange as it all works fine for quite a while. I may however mis-understand to use the battery, so what I have is ONE 12v battery
Batt+: to arduino 3.5mm input, AND LEd+
Batt- : to arduino 3.5mm input AND Arduino GND
LED ground : GND input on arduino
Signals: LEds have 2 signal wires each going to one digital i/o.
Is the battery correct? Should I just get a separate supply for the arduino? I think the GRN is wrong perhaps.
What do you mean by LED+, Led ground, and LED signals?
You can control one LED from an Arduino pin by connecting a current limiting resistor from the pin to the LED and the other side of the LED to either ground or +5v, depending on whether you want the led to be on or off when the pin is high, and observing correct polarity of the LED. What you must not do is connect the other side of the LED to your battery or anything else that is at more than +5v.
If the LEDs are red, you can probably connect two of them in series and drive them from one pin in the same way. To drive more LEDs, you will need to use a transistor to switch them, or use multiple Arduino pins. Using a transistor allows you to run the LEDs from a high voltage supply (e.g. your battery), allowing you to connect more LEDs in series.
Yes, sorry it may have seemed confusing about the signal wires. I am using these ones: http://www.bliptronics.com/item.aspx?ItemID=88 from bliptronics. The circuit I have wired is as pic attached. The batt is like 7 amps. Should I use a separate batt or where would this resistor go in this circuit. I have around 160 LEDS wired up.
Yeh , it does look a little off now looking at the diagram with 2 wire going to the ground. To answer your question, one goes to the GND on the arduino and other other on the power in plus. Would this be frying the arduino? To use seperate power supplies they say you must connect the ground together. Is this done on the arduino board itself or from batt to batt?
You have something else wrong. The LEDs according to the web page are controlled by SPI data and clock signals. There should be no way for those to get large voltage on them.
Exactly what chip is getting hot? If it is the ATmega chip then I suspect you have misidentified the wires. Do some measurement with a meter at least and check the voltages.
Seems strange as it all works fine for quite a while
Not strange that is what happens sometimes when you get things wrong.
To name the pins, as per the diagram the batt has a positive and a negative going to the arduino 3.5mm power input plug. Not sure what this is called. The GND on the arduino is labelled GND on the arduino and the signal wire are just digital 11 and 12. What gets hot is the actual chip. I will try and just use a seperate batt for the arduino BUT does this mean I must put a ground wire from the LED battery to the Arduino GND terminal?? I still dont get where to connect the ground together, on the Arduino or direct to each battery. Thanks again for your help. I am acutely aware of how stupid I am.
One possible explanation is that your ground connection to the LED module is intermittant. If this ground connection breaks, the LED module will try to get its ground current from the Arduino outputs through the 2 signal wires. To protect against this, you could try putting a 1k resistor in series with each signal wire; but as there are no specs for the LED module on that site, I can't say for sure that this won't prevent the signals getting to the module. If it does, then reducing the transmission speed may help.
I still dont get where to connect the ground together, on the Arduino or direct to each battery.
It doesn't actually matter much providing there is an electrical path between them.
What you need to do now is to get a meter and measure the voltages on the arduino output pins. The circuit as you have described it should work, the fact that it is not suggests:-
You have not wired it up as you think you have, a photo posted at this point would be good.
That module requires a 12V signal drive and not a 5V one and so you are getting voltage back fed into the arduino.
Thanks for your help. I rewired the whole thing and also used a seperate power supply for the arduino. I think the suggestion that the ground was losing connection and it was putting a full 7 amps though the arduino was correct. I do appreciate all your help on this. I will post a pic of the project once finished.
