We’re trying to use a Spark motor controller with a CIM, and controlling it with an Arduino. However, the status LED on the spark starts flashing rapidly, switching between the different colors very quickly, and the motor sounds like it’s trying to keep up with what those colors mean. When we swap out the motor for a VEX motor, it works perfectly fine, so I would assume the issue lies with using the CIM. Any ideas how to fix this?
What motor is it working with? VEX makes several different motors.
A picture of your setup may belie an electrical issue, or at least help us understand your not-FRC-spec system. (Which may be totally fine, but it merits extra scrutiny.)
I was actually wrong about it being a VEX motor, it’s this motor from REV. You’re right about it not being an FRC compliant system, this is a project we’re doing with another group at our school. I can’t get a picture of it right now, but we’re using an arduino nano to send the PWM signal to the spark. The voltage going into the spark is 9v. I’m aware it’s supposed to use 12v, but we’d like to avoid using 12v batteries, as that would add a lot of weight and cost to the project, and the 9v works perfectly fine with the REV motor. It’s only when we swap it for the CIM that this issue occurs.
Well there is your problem the 9v supply. I’m betting it can’t provide the current that a CIM needs, that causes the voltage to sag to the point where the Spark doesn’t have enough voltage to operate itself. The Rev motor has a 12v stall current of 4.4a while a CIM has a stall current of 133a.
I agree with Mr V. The CIM draws a significant amount of current at startup and with a lower voltage supply, it is likely that the supply is dipping below the 5.5V absolute minimum the SPARK requires to stay operating.
Do you have a link to or a list of the specifications for your 9V supply?