How to connect SMC to TReX Jr?

I have with succes connection from Pololu Trex Configurator using USB->TTL conversion cable.
(connected ground,Rx,Tx). Configurator version 1.3

But when trying to use simple motor controller in same hardware setup the TReX Jr is not found. All parameters and buttons are greyed out ??

I need to control two DC-motors and to have analog limit/kill switches for my application. Thus I hope to be able to use the SMC software…

Am I on a wrong track or just missed a detail ?? :smiley: :question:

Hello, Birger.

I am sorry you are having trouble with the TReX. It sounds like you have both a TReX and a Simple Motor Controller connected to your computer and you are having trouble connecting to the TReX using the TReX Configurator software. I suspect that you are not selecting the right COM port when you connect to the TReX. You should make sure you select the COM port for the TReX and not the one for the Simple Motor Controller.

If that does not help, please tell me how everything is hooked up, what COM ports you have on your system, what your procedure is for connecting to the TReX, and what error message you see.


Thanks for quick response.
However I must have been unclear… I have succes using the TReX configurator <> USB-TTL<> Trex Jr. Using com9…

But when I try to use the software SMC as controller for the Trex JR it can not see the TRex Jr.
As I can not control the use of com port in the SMC I do not know how to help it to establish contact with the TReX Jr.
All buttons and parameter-boxes are greyed out.


The Simple Motor Control Center software is only designed to work with the Simple Motor Controllers, so you will not be able to use it with a TReX.


Ups… I was afraid it was so…

So now I am searching for a solution where I can start and control two DC-motors speed and use analog limit/kill switches for end stop’s .
May be it is not possible using the TReX Jr?
If so then what is a simple solution?

In addition I need to ensure very low acoustical noise and thus I work on a encapsulation box, and why I want to use DC motors at relative low speed in order to lower the emitted sound.

Hope for some inspiration…

Well. May be I simply try the Pololu Simple Motor Controller 18v7
Then I have both USB control for initial setup, testing etc, and then TTl when using the motors for controlling the position of microphones.
The TTL-control is important, because the acoustic measurement system is capable of this in its measurement sequences.

Any comments on this or alternatives are very appreciated. Yours Birger

The TReX does not have a limit switch feature, so using a Simple Motor Controller sounds good.


Well now it works fine using USB and analog control’s, BUT not when trying to connect using USB to TTL (Adafruit cable)…

I repeat this question as a new topic… SMC…