Help with the buying and wiring of LEDs

[iLloyd]

We need help with LEDs. Our plan is to have a ultrasensor on the robot and the LEDs show green if the robot is the appropriate distance and yellow if not. Our problem is we don't really know which LEDs to buy. We also are we planning on wiring the LEDs to a spike to control it, are we thinking about this the right way? We would rather not have to use an Arduino.

Thanks!