Hi, I am currently putting together a small lego CNC mill. The aim is to be able to cut some small shapes out of flower foam or balsa etc. I have tested all 3 axis seperately and now I am progressing to a test with all 3 axis moving at once and then on to adding the drill motor. The 4 aa battery pack that I was using to test this I believe is under-powered to run all 3 stepper motors at once so I am trying to look at a more stable solution.
I have a laptop power supply at home that provides 19V and 2.1A and has a centre positive barrel jack. I have got a breadboard barrel socket. The 3 stepper motors are 28byj-48 controlled using my Arduino Uno and 3 ULN2003a development boards which have a specified 5-12V input.
The 4th motor is an old motor I have from an RC helicopter. It was run off a 7.2V re-chargable battery.
Would it be possible to use this power supply and use a voltage divider to reduce the voltage from 19V down to something like 8.4V using a 2.2 kilohms and a 1 kilohm resitor?
I have a concern that the current going through the breadboard would be too much in the prototyping stage. I could possibly use some protoboard to make a small power circuit or order one of the small quadcopter style power distribution boards and use that.
Would my circuit (picture below) work in principle? I could power each stepper with its own battery or just beef up the current battery pack from 4AA to something bigger but would prefer a more long term solution.
All suggestions or comments welcome and appreciated.