I am working on a project which requires a pan and tilt mount controlled with servo motors, a speaker to be run off the MC (via a DACs and amplifier) and mic input to the MC (via external ADC and bias). I am currently using 9 V batteries for this project.
At this moment i am running each servo off one 9V battery via a 6V regulator but now i am thinking of chanigng the circuit to 2*9V batteries in parallel. Which should supply enough current for the servos and the MC, Also unsing the ~9V rail to connect the two 6V regulators for the servos and a 7805 for the MC.
I might have to add another 9V for the DAC / ADC but not sure on that. Am i missing something or this seems correct.
You will find that 9V "Transistor" batteries (the rectangular ones with clips one the top) will have a very short life when you are drawing significant power (like a Servo). You would be better served by a battery box of six AA cells. You could tap off 6V for the servos and save the drain of a voltage regulator.
AbdulW87:
Am i missing something
No, but I suspect you're not personally paying for the batteries...
Do you mean "PP3" batteries?
If so, like the others, I think you must be joking! Even more absurd to use them with a regulator for servos.
For 9V, you should be using a carrier with six AA alkaline cells at the minimum. For the servos, a separate carrier with four AA alkalines or better, since they require 6V and no more. In fact, the Arduino will probably operate very happily on 4.5V - three alkalines.
Arduino does run very nicely on 3 AA batteries. I use that for power when installing bootloaders and I need power for Atmel Ave ISP MKii.
(I should modify mine to make its USB power available)
so four AA for both servos without the regulator circuit (regulator, capacitors) should provide enough current, and the Atmega328 can run from a seperate block of AA batteries.
I am using the 9V batteries since i used them last year for another project with 7805 to provide the 5V for the MC and other things so seemed like a good place to start.