We would like to have indicator lights on our robot to tell postion of certain things. Can we power the led’s off of the 7.2 v battery ? If not how else should we power them. All they would have to do is have led’s powered.
There are +5 lines on all of the digital/analog pin groups. You also have the +12 from the main battery. I would avoid the backup battery, as its connector is designed to be plugged into the RC directly and the whole point is that if the rest of the robot fails, it should keep going. (Unlikely that the LEDs would change this, but you never know…)
Here are two helpful links to make sure your LEDs live long productive lives. They’re actually about using LEDs as computer caselights, but there’s plenty of meat about wiring and using an inline resistor to make sure you don’t kill the LED with thermal runaway.
A normal LED caselight
A Luxeon Star caselight
I’m uncertain how visible a normal high intensity LED will be across the field. The Luxeons are MUCH brighter and bigger, so you’re more likely to see them. They can draw up to 5 Watts at 7V, though, so I’m thinking running off the digital IO might be a bad idea, as I’m not sure what those are rated at. I’m doubting many sensors draw even 1 watt of power when operating, though.