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Picaxe Power Supply, (picture) 4 Servos

I am going to run 4 servos with my picaxe. I currently have the 3 AA battery pack connected to it.  I am wanting to add an additional 6 volts (4AA) pack running directly to the servo.  The 3AA Pack is already connected to the V G spots in the picture. I am confused about where to sauder the 4AA pack so all the power goes directly to the servos.



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The reason it won't work is the fact that the darlington pulls low. I.e. if you input a high signal, the corresponding pin will be pulled to ground. Remember, the darlington is just a bunch of NPN transistors and a diode. High goes in, low comes out -- the servo pulses would be "reversed".


Of course. Thanks.

Sorry about the darlington in the picture, I am working with a group in my engineering class.  We actually have 330 ohm in place of the darlington.  Another guy in our group has the picaxe at his house right now so I couldn't get a more current picture. 

Thank you for all your help! The bot should be ready by next thursday climbing the stairs. hopefully :)


Sure, desolder and yank 'em out or use an old servo connector or solder to the pins and shrink wrap. Whatever.

Awesome, I know what to do now, thanks for the help.

Far left is V2, far right is gnd.

In terms of what you should do? Connect your second power supply to the pins. I gotta be missing something here in terms of your question... V2 will be positive and gnd is ground. Red to V2, black to gnd. I don't know how else I can answer this. Hook up your power to the pins. That's it.

BTW the servos won't work with your darlington plugged in.


Hey CtC,

I'm curious why the servo wouldn't work with a darlington chip plugged in. Surely the darlington can drive enough current for the servos.

I'm not doubting you, just wondering why.

Sorry I am new to this.  I was wondering because my first power supply is connected to the V,G slots and are just soldered to the bored.  Where the second supply is suppose to go is 3 pins, I was confused about weather I should take the pins out of the board and solder to V2 and G or just somehow connect the red and black wires to V2 and G pins.

Read through this post very carefully, it will explain how all the pins on the Picaxe Project Board are used, including how to run two separate power supplies (V1 and V2).



I read that, I am a bit confused.  Where I supposedly put the second power source are 3 pins poking up. So first one is V2, the middle one would be V1 and then the one on the right is ground. So I am assuming I need to connect V2 and Ground here.  My first power source (v & g) is saudered to the picaxe.  What are you suppose to do with the 3 pins poking up for the 2nd power source?