I am upgrading the lighting in a model with simple circuit which has 17 LEDs (approximately) plus one or two 555 timers. Presently, everything is powered by 3 AAA batteries. It drains between 150 and 250 mA (depending on how many LEDs I switch on). Heads up: I'm new to electronics and lighting, so please bear with me anyway if the questions if not challenging enough :)
Once the circuit is done, I plan to extend it with two variations:
- Arduino Version: connect the LED circuit directly to the output pins (5V) of an Arduino board, with a resistor in each wire to compensate for the +0.5V excess.
- USB wired powered version, using a wall charger USB that provides 5V 800mA.
My question is: What should I do to adequately protect the circuit when using the USB version? Do I need a voltage regulator? If yes, what type/part?
As per my research, I don't need a regulator for the Android version, but I'm not 100% sure (comments on that will be welcomed too).
Edit: As requested, I've added a simplified schematic. The final version will have more leds and probably drain arround 200mA-250mA.