Newbie to Arduino and electronics in general here. I have found some topics on powering motors on this forum and elsewhere but to be honest the information confused me more than it cleared things up.
I just want to use an Arduino Uno and the Adafruit motor shield to power a 12v 0.4A Nema motor recommended by e.g. Adafruit, maybe add some more motors later. The motors shall be controlled via PC over the Arduino USB connector. On the Adafruit website I read
Setting up your shield for powering DC and Stepper Motors
...There are two places you can get your motor 'high voltage supply' from.
One is the DC barrel jack on the Arduino board
The other is the 2-terminal block on the shield that is labeled DC Motor Power 5-12VDC.
If you would like to have a single DC power supply for the Arduino and motors, say a wall adapter or a single battery pack with 6-12VDC output, simply plug it into the DC jack on the Arduino or the 2-pin power terminal block on the shield. Place the power jumper on the motor shield."
That sounds quite straightforward and simple to me. Just plug in a 6-12 V DC power supply into the Arduino jack and that's it? I'm asking because I keep reading about all sorts of problems with powering motors. I wonder whether I'm getting something wrong here.
I may be wrong but I think powering your shield and so your motors just with the 6-12VDC input of the arduino will not work, the motor will drain too much current for the little SPX1117M3-L-5 on the arduino (voltage regulator), and your arduino can only output 5V or 3,3V, not the 12V needed by your stepmotor
On some adafruit shields, powering the shield powers the arduino too, you should try if it's your case.
What is a "Nema motor"? Never heard about that before.
Can You post a link to the datasheet of that motor shield?
Arduino boards should never supply power to stuff like motors, solenoids etc,
If you use the V2 Adafruit motor shield (not the V1 with L293 chips) then you can drive that low speed/torque 30ohm hybrid stepper from Adafruit. But not most other moderns low-impedance steppers.
You can power the setup via the DC socket, which also powers the Uno when you leave the jumper on the shield on. You can also connect 12volt to the shield's screw terminal instead of the DC socket, which bypasses the DC socket's reverse protection diode, and that is the preferred way for two motors.
12volt is borderline high for an Uno, and you can't power much else at that voltage from it.
If you must, then remove the jumper, and power the Uno with a 5volt USB cellphone charger, connected to the USB socket.
If you're serious about stepper motors, then don't use that shield and that hybrid stepper.
Use a CNC shield that can hold 1-4 current controlled stepper drivers for more modern high-speed/torque low-impedance stepper motors. And a 12 or 24volt supply.
Leo..
[quote="SyFizz, post:2, topic:1084947"]
your motors just with the 6-12VDC input of the arduino will not work, the motor will drain too much current for the little SPX1117M3 [/quote]
You are correct on the 800mA if the voltage is not to high on the input. Since the motors are connect on the input side of the regulator explain how will it cause it to shut down.