I'm using a 9 volt battery to power the Arduino, then using the Arduino power supply to power my sensors (so far 2 IR range finders and an ultrasonic) so that will give 5 volts to the LED's. That is too little to run the in series... There is also a 3.3 volt power supply that can come from the Arduino, so should I use that, and add resistors to the LEDs so they equal 3.3 volts each instead of 1.5? Or would that be too much waste...
For the whole board, I'm imagining it with 2 power wires, then 5 output wires, one for each of the detectors. Correct? Is there anyway to slim it down to less then 5? I only have 6 analogue inputs, and 2 are being used by the range finders. I might have to make it either a obstacle avoider or a line follower, not both. The only ways I can imagine using less wires are pretty complicated, and require a new controller to process the line following module, then outputting only 3 wires, telling the Arduino to go forwards, left or right. Kinda like a master/slave setup. But thats too complicated for now, just going to use 5 control wires. Is that correct, and will work out ok?