I had a similar problem with a micromouse robot, turning on the motors would crowbar the power supply and reset the microcontroller. I solved this by a diode from the battery to a 100uF cap to the microcontroller power supply. I connected the motor driver as close to the battery as practical.
You need a good (low resistance) 0V between the microcontroller and the servo, and I would recommend a 1k ~ 10k resister in series with the control signal. On Sunday, 20 September 2020 at 20:44:39 UTC+1 [email protected] wrote: > In this this Rubik's Solver project there is a note in step 2 of the > Software Preparation section where they make a change in > 'libraries/other/rc_pru.c' of the Strawson Design Roboticscape software to > set the "servo pulse from +/- 1.5 to +/- 2" > They seem to be able to run with 6 servos attached so perhaps this would > help. > > > https://www.hackster.io/octavo/iot-robot-w-osd335x-powered-beaglebone-blue-rubik-s-solver-5891a4 > > They also have a Li-Po battery connected. > > Cheers, > > Jon > > On Sun, Sep 20, 2020 at 5:55 AM <[email protected]> wrote: > >> Experience the same, one or two servos work. Adding more and I see issues >> which look power related, jittering. >> >> On Tuesday, 17 December 2019 22:50:19 UTC, [email protected] wrote: >>> >>> I'm using a TowerPro SG90 Micro Servo and having trouble getting it >>> powered through the Beaglebone Blue. I apologize for the wall of text, but >>> i've tried quite a bit before coming here and want to make sure you all get >>> everything I've found. I also apologize for the lack of pictures, i didn't >>> photo-document things, but I have tested everything multiple times. >>> >>> *Problem: When attempting to drive servo(s) from BBB's powered servo >>> rail, servo(s) just click and don't move at all.* >>> >>> SG90 info: >>> Signal 50Hz >>> V+ : 4.8-6V >>> >>> Connected to BBB by USB cable. Connected 14.4V (up to 60 Amp) power >>> supply to DC in. >>> Tested Items: >>> >>> 1) When no servo's are attached, powered rail is 6V (TRUE) >>> 2) When no servo's are attached, signal rail has 50Hz (TRUE) >>> >>> Add servo to setup >>> >>> 3) Signal rail is still 50Hz (TRUE) >>> 4) Powered rail is still 6V... >>> 4A) At (normalized) pulse of 0 (TRUE) >>> 4B) At any other pulse width (FALSE) it varies between 1.2V and 5V >>> >>> At this point the Voltage rail is fluctuating wildly. I decided to >>> check if there was an induced signal in the voltage rail. >>> >>> 5) Frequency on Voltage Rail at ALL non-zero (normalized) pulse widths >>> is 4Hz >>> >>> So i decide maybe the servo is bad. >>> >>> 6) All above results duplicated across 3 known good servos >>> >>> So, lets try pulling power from somewhere else. >>> >>> Using a 5V bench power supply with SEPARATED ground from BBB >>> BBB Signal - signal in >>> Bench 5V Power - V+ >>> Bench Ground - V- >>> >>> Yes, bad design. Should use BBB Ground, or tie BBB ground to bench >>> ground... but >>> >>> 7) Servo runs as intended. >>> 8A) Check V+ for induced signal (None found) >>> 8B) Check V+ for voltage variation under load (none found, always 5.2V) >>> 8C) I'm unable to measure the current with my setup, however specs say >>> 550mA for this servo. >>> >>> So... Now we fix some things up. >>> With Bench supply 14.4 V to BBB DC in this scenario the 5V is achieved >>> by a DC-DC converter (10-15)V - 5V. So the ground is ultimately shared by >>> all connected electronics. >>> >>> 9) Repeat all test with same results. >>> >>> Am I missing something? Does my BBB have a bad power supply for the >>> Servo Rail? What else can I try? Software used to test this is the >>> Robotics' Cape test software >>> http://strawsondesign.com/docs/librobotcontrol/rc_test_servos_8c-example.html >>> >> -- >> For more options, visit http://beagleboard.org/discuss >> --- >> You received this message because you are subscribed to the Google Groups >> "BeagleBoard" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/beagleboard/79fa8c17-a6af-4304-842d-f5af4288fe3eo%40googlegroups.com >> >> <https://groups.google.com/d/msgid/beagleboard/79fa8c17-a6af-4304-842d-f5af4288fe3eo%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/4b9c8058-6bec-41d9-8d2f-e30a0d749ea4n%40googlegroups.com.
