Thank you both for your replies,
A few things I forgot to add to the circuit diagram:
Motors A & B both have large ferrite cores which came looped on to the 14 AWG leads.
For the Adafruit DRV8871 gearmotor C driver, I removed the smd resistor (3002 – 30KOhms?) and added a 20KOhm resistor to increase the current limit of the driver as described in page 9 of the DRV8871 driver pdf.
I’ve also soldered a 0.1uf ceramic capacitor across the gearmotor C terminals.
I’ve not intentionally added any decoupling capacitors to the circuit – unless these components are included on the driver boards?
The IBT-2 drivers have what I think is a large black electrolytic capacitor next to the battery terminals, it is rated at 50V and 330uf – I’ve attached a photo, see what you think. Should I still add a 100uf electrolytic capacitor?
For the sensors, should the 10uf be an electrolytic capacitor and the 0.1uf ceramic? I’m guessing I need to solder these as close to the sensor VCC, GND pins as possible?
Motors A & B use 14 AWG stranded wire, they are connected to the screw terminals which came pre fitted on the IBT-2 motor drivers
Gearmotor C uses 18 AWG stranded wire. I intended to solder them directly to the board but the holes were too small so I soldered the supplied screw terminals and am using those – see picture
For the Adafruit DRV8871 gearmotor C driver, I’ve soldered the supplied male header pins to IN2, IN1, VM AND GND and the supplied screw terminals to MOTOR and POWER. Should the capacitors be soldered to the 18AWG wires going in to the POWER terminals – see attached picture. It says on this page, second picture down ‘These two sets of pads are connected internally’. If so, should they just be soldered as close to the POWER screw terminals as possible?
Would the required capacitors for the DRV8871 be a 47uf electrolytic and a 0.1uf ceramic?
What I don’t understand is how motors A & B are right next to both speed sensors yet they don’t seem to cause interference. Yet when I turn the gearmotor C on (which I’ve even moved 6’ away) all of sudden it causes the motors A & B to start stuttering and the speed sensor readings start going erratic.
If there is anymore information, pictures etc on the setup, which might help, just let me know.
Thanks,
Michael
