Velocity motorbike

Hi everyone!

I'm an amateur when it comes to circuits but I've just started up a hobby project. The aim is to construct a speedometer that will show the motor cyclist it's speed through three different LEDs showing different colours. Green, Yellow and Red. Green = speed below speed limit, yellow = you´re reaching the speed limit (warning!) and red = you´re going too fast!

Since my knowledge concerning circuits is quite limited I'm in use of anyone´s help.

I'm thinking about using:

Battery
3 LEDs
GPS
Light detector (to know whether to increase the LED's light or not)
Micro controller
A couple of resistors

I've added my schematic of how I think the circuit should be built.

Question is: what other components should be added?

Thank you in advance!

Apart from an 'off' switch you've probably got enough components there, unless you're proposing to power the circuit from the motorcycle's battery; in which case you might well need a voltage regulator and associated smoothing/suppression components.