thanks for your help.
I am really, REALLY ignorant about all this, as I am a neuroscientist and I have just a minimal knowledge about electronics. I tried googling around and studying a bit, but I am still confused. I write asking your help because I can’t seem to be able to figure out a couple of things in a small project. I am trying to build a motorized syringe pump to deliver sugar solution to reward animals (simplified version of what is described here: https://github.com/chen42/openbehavior/blob/master/operantLicking/Assembly.md ).
In the “POWER” paragraph, they indicate that I would need to cut a 12V AC-DC converter and connect it to a DC-DC step-down set to 5V. Basically the output (5V) should go towards a mini-USB connector that (from what I understand) should power the raspberryPi. On the side of the input to the DC-DC step-down, from the figure, I should connect wires that will power the Pololu step-motor. If I understand correctly, this would bring the 12V to the step motor, right? From the specifications in the Pololu webpage, it looks like the step-motor needs only a minimum of 3.8V, but from the Q&A I understand that a higher voltage can and should be applied, as the motor (through the step motor controller) will draw power (670mA) as needed.
Now, my question is: instead of using the 12V AC-DC converter and then scaling down the DC-DC with the step-down, can I use the AC-DC converter that outputs 5V that I got with the raspberryPi? In principle, could I just open the wire, branch it (doubling the wires, basically) and power both the raspberry Pi and the step-motor? Would this work, or am I completely not understanding how all this works?
Thanks a lot.