Right I have my project all set up ...but... I need power, I thought it would be easy but after later calculations its harder than I thought.
Soo 12v in a car isn't usually 12v for very long at all. 14.4v or thereabouts whilst the engine is running and about 8v while the car is starting up etc.
I thought about using an in car charger that outputs 5v but i found out the one I have outputs 700ma which means my car battery would only last about 62 hours (about 2 and a half days).
Could I not use a voltage divider to take the 12v and convert it to 5v? Well something like this:
Vin: 14v | R1: 5KOhm | R2: 3KOhm | Vout: 5.25v = Power dissipated by circuit = 24.5mW (Which works out at about 2mA? Correct?)
Vin: 8v | R1: 5KOhm | R2: 3KOhm | Vout: 3v = Power dissipated by circuit = 8mW (Which works out at about 1mA? Correct?)
^ That info was calculated using Electrodroid for Android
So in this case, would it be okay to use a voltage divider or is it not such a good idea?
I have the arduino, an RF receiver board and a bluetooth board to power (RF board is taking power from an arduino pin thats set High and the bluetooth is using the arduino's 3.3v supply.)
Any help is much appreciated.