Architect Project Using Multiple Servos External Power Supply GrasshopperFirefly

Hey there, I have two arduinos and I am looking to control one 12v stepper motor and eight 5v servo motors using Grasshopper & Firefly. The algorithm on Firefly is sound however, I have now realised that a single arduino does not provide enough current to supply more than 2 servo motors. I am therefore attempting to use an external power supply of 5v using four 1.5v AA batteries connected to a Voltage Regulator and pair of capacitors. I also have a transistor to allow an increase in current in order to power the 8 servos on a single board. Then I would be attempting the same but on a second arduino with 12v external power supply for the stepper motor.

I'm unfortunately new to the physical wiring of the circuitry and I am not sure if this will work and if it does how exactly to wire it?

Any help would be much appreciated

JamesNess:
I have now realised that a single arduino does not provide enough current to supply more than 2 servo motors. I am therefore attempting to use an external power supply of 5v using four 1.5v AA batteries connected to a Voltage Regulator and pair of capacitors. I also have a transistor to allow an increase in current in order to power the 8 servos on a single board. Then I would be attempting the same but on a second arduino with 12v external power supply for the stepper motor.

A lot of this does not make much sense.

It is not wise to power any motor or servo from the Arduino 5v pin.

Servos should work fine from 4xAA batteries without any voltage regulator. What is your voltage regulator supposed to do.

I have no idea what you want a transistor for. Just connect all the servos to the battery - if there is not enough current you need a bigger capacity battery (same voltage), not a transistor.

Post a diagram of how things are wired. A photo of a pencil drawing will be fine.

Stepper motors are more complex because they need a stepper motor driver board between the Arduino and the motor. Post a link to the specifications for your motor and for your driver board.

I don't immediately see any need to use two Arduinos - unless they are for separate projects.

...R

Yes apologies, I have just bought what a member of staff recommended to me as I am fairly new to this. I bought a voltage regulator to take the 6v supplied by 4 AA batteries down to 5v but after experimenting I recognise it is ok to use the batteries direct. The Mosfet transistor is used as a switch I think, I have attached an image of how I have wired one servo. (This also includes a diode to prevent back current) This seems to work for multiple servos now however it does mean that a single servo takes up 2 pins on the arduino? I’m not sure if theres a way round this, it seems to me that you’re saying I can wire these direct without mosfet transistors/diodes?
The stepper motor I have purchased is
http://www.ebay.co.uk/itm/161382246834?_trksid=p2060778.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
although I have not purchased a motor driver for it yet (not sure which one or if they work on grasshopper/firefly?) I thought I would possibly need 2 arduinos as they will need different voltages and there are not enough input pins on one to control everything? (9 available through grasshopper/firefly)

Thanks for your help again!

A servo only needs one connection (signal) and a GND connection. One GND connection will do for all the servos.

If the servo power supply is separate from the Arduino there is no worry about reverse currents.

I think that stepper motor is the same as the ones I have. I am using Pololu A4988 stepper drivers.

The A4988 just needs 2 Arduino connections per motor - step and direction (plus GND).

I don't know what grasshopper/firefly is. Perhaps you can post a link.

...R