Author Topic: Choosing a Battery/Modifying the Servos (For $50 Dollar Bot)  (Read 1665 times)

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Offline ksquaredTopic starter

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Choosing a Battery/Modifying the Servos (For $50 Dollar Bot)
« on: April 28, 2011, 08:58:16 AM »
So, I think I finally have the brain for the $50 robot.  But it has left me wandering about choosing a battery for actually running the whole bot.  I have it wired up so that it relies totally on the 9-Volt for power, even though I have a battery pack.  Is it worth it to desolder and simply attach the battery pack? It says in the tutorial that your overall power 'could be several amps' and I don't know how well a 175 mAh battery is going to stand up to that.


Also, I had an alternative method for modifying servos that I strikes me slightly more robust than gluing things down.  It was based on a mix of two other methods I found online.  Basically, I desolder the motor to take out the board, take off the potentiometer (perhaps use polish remover, acetone, to dissolve the glue?) and find the resistance when it is equal between the two terminating pins and the middle pin - assume that this is the middle point - and then insert resistors to simulate that (or can I just insert two identical resistors around this value?  Does anyone know this value?)  Tuck it away and hope it works...

Or would it be more advisable just to use the method described by SOR?

The motor seems to have survived the abuse of the servo being disassembled on this one I'm working on, at least. 

Either way, I know its kind of a long post, thanks for any help!

Offline waltr

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Re: Choosing a Battery/Modifying the Servos (For $50 Dollar Bot)
« Reply #1 on: April 28, 2011, 09:23:48 AM »
A 9V battery will run the processor but not the servos. If you have another battery pack then you could use it if the voltage is in the proper range. Which battery pack do you have?

Yes, using two fixed resistors is one way to modify a servo for continuous rotation. The values will, most likely, not be equal. You need to determine what values will work. I'm sure the instructions you found give the method to determine the resistor values.

FYI: There are many threads on this forum about the $50 bot. Do read through them as your questions are quite common and have been answered. You will have additional question that also have been asked and answered so these threads will help.

Good luck and keep us posted on your progress.


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