Which product should I use?

My project triggers a Mabuchi RS engine 380 4122 DC 3.6V, which the drivers should I use?
JRK Pololu 21v3 USB Motor Controller with feedback or Pololu 12v12 JRK Controller USB Motor with feedback


Can you post a link to the motor’s specifications or tell me the stall current of the motor you are using? Also, is there a reason you are considering the jrk controllers specifically (e.g. do you need feedback for your application)?


This is the engine that I use in my project,

I need feedback on my application. I accept suggestions …

I did not see any feedback on the motor you linked to; what kind of feedback are you planning to use in your system? If you are not sure what kind of feedback you need, can you describe what you want the motor to do in your application?


I am developing a Sail Winch to my radio controlled sailboat, where strength and accuracy should be allies. My apologies for my english !!!

You might consider using something like a potentiometer and attaching it to the sail mast so you will have analog feedback for closed-loop position control.

If you do that, I would recommend the Jrk 12v12 USB Motor Controller with Feedback to work with your motor (since it can have currents up to about 6A). You can connect your potentiometer to the FB, 5V and GND pins shown in the “Module and Pinout and Components” section of the Pololu Jrk USB Motor Controller User’s Guide. Information about configuring the feedback and RC input can be found in the “Feedback Options” and “Input Options” section of the same user’s guide.

Your sailboat project sounds fun! We would love to see how it turns out!


Mr. Derrill,
As per your suggestion I bought a Pololu Jrk 21v3 USB Motor Controller with Feedback, but before I did the engine consumption measurement and result was 2 A. Well, the product arrived and I made the connections to work with radio control, and just got the Led flashing yellow. I would like to get a help to connect properly and perform setup. I’m a curious modeler, and my understanding of electronics is difficult … Help me!
See the pictures at https://www.dropbox.com/sc/iogf8felbufbh6h/AAAUfOpG3Ycj0zclQ5mso4jka

It is not clear from your pictures if your potentiometer is wired correctly or not. Can you measure the voltage at the FB pin with a multimeter to see if the voltage changes from 0V to 5V when you turn the potentiometer to its extremes?

If you have not configured the feedback and input options as I suggested in my last post, please do so following the instructions I linked to. If you have appropriately set those feedback and input options, can you post your settings file? You can save the settings file by selecting “Save settings file…” under the “file” menu at the top of the Jrk Configuration Utility.


I will follow your instructions, but first I would like the verification if this is correct the installation of the potenciomentro, I made the measurement between the FB and the GND, and FB and auxiliary, there was tension. I’m sending new photos for verification …
TKs …

If the potentiometer connection diagram in your first picture is correct, those connections seem fine. Did you get readings between 0 and 5V when you tested the reading between FB and GND?

The voltage between FB and GND 2.4 volts, between FB and auxiliary 2.3 volts, measured in the potentiometer … when rotated has voltage variation …

Your wording regarding your multimeter readings over the rotation range is ambiguous, so I cannot tell if your potentiometer is connected correctly or not. When correctly connected, you should get a reading between the sweep of the potentiometer and ground of between 0V and 5V when the potentiometer is turned from one extreme to the other. If you are not getting those readings, can you post a link to the potentiometer’s specifications or pin out so I can see what the pins on your potentiometer are?


Derill, I am sending photo link to conference installation of the 5mm Baurns potentiometer with the board.
There was a progression, I installed the driver on the PC, I made tests, the result of the diagnosis, there was an input error, now in the morning I’m performing a new test with the power center installed on the servo. As soon as I finish I inform the result …

Derrill, I took the test now, the servo that the one on the board (power output) is working. However the servos that are connected to the RC receiver are jammed when connected to the Jrk board, when powered and connected to the RC receiver, they work properly …

Derrill, I took the test now, the servo that the one on the board (power output) is working. However the servos that are connected to the RC receiver are jammed when connected to the Jrk board, when powered and connected to the RC receiver, they work properly …

Derrill, the scene changed, motivated by the instability of the system, I rebooted the PCB and after I am not getting a configuration and so the engine is not working with before … I need your help !!!

The current state of your system is not clear. With nothing else connected to the jrk, does the Jrk Configuration Utility show the jrk connected in the “Connected to:” box?


Derrill, I reinitiated the jrk, I made the reconfiguration, everything returned to the norm, except the instability of the system when connected to the RC … when I activate any servo of rc happens the instability. Note when only the jrk is rammed the servo connected to it runs stable.

Derrill. If not configured properly, can the PID cause system instability?

Your PID settings can definitely cause problems like that. You should follow the directions under “Tuning the PID constants” in the “Setting Up Your System” section of the “Pololu Jrk USB Motor Controller User’s Guide” to set the PID parameters.