Hello.
I bought a Dual G2 High-Power Motor Driver 24v18 Shield for Arduino.
I tested the Demo.ino program and it works perfectly with an Arduino Uno R3.
However, it doesn’t work with an Arduino Uno R4. My PC doesn’t recognize the Uno R4 when I connect it with the shield.
Is this normal, or is there a solution? Thank you in advance for your help.
I believe, the library is not yet updated for ARduino UNO R4. You may need to modify the library. However, the issue that you’re facing now is not related to the firmware. It’s a hardware issue. Dual G2 High-Power Motor Driver 24v18 Shield was designed for UNO R3. I believe, The Hardware itself is not compatible with UNO R4 directly. If you are sure that your UNO R4 is alright and it is working properly when NOT connected to the shield, then I suggest that you use a separate power supply for the shield while keeping the grounds tied together.
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Yes, the Uno R4 works perfectly without the shield, no doubt about it.
I thought this issue was already known. Am I to understand that I’m the first to mention it?
Currently, I am not at home and therefore will not be able to test separate power supplies, but I promise to do so as soon as I return home and give you feedback.
Thank you very much for your attention.
Hello.
We have not thoroughly tested the Dual G2 High-Power Motor Driver 24v18 Shield and library with the Arduino Uno R4, but I just tried it with a unit I have here and it seemed to work fine with our Demo.ino program (although please note that our library will use analogWrite() for the PWM signals instead of timer1, so they will be at 490 Hz instead of 20 kHz).
As justbeatit suggested, it sounds like you are running into a hardware issue if your PC isn’t seeing your Arduino when you connect the shield. Do you have the ARDVIN jumper installed, and if so, are you connecting it to VM or VREG? What are you using for your VM supply? Also, could you post some pictures of your setup that show all of your connections, as well as some close-up pictures of the underside of the driver shield showing your soldering?
Brandon
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The jumper is connected to VREG.
On the big connectors I have connected a little motor on M1A and M1B, and a 3S battery (11.4V) on GNG and VIN.
Those are the only connections even with UNO R3 or UNO R4.
With the UNO R3, everything is working fine. With the UNO R4, my PC don’t reconize it. But if I take off the shield, the PC reconize the UNO R4 very well (only connected on USB).
Unfortunatly, I am not at home for a few days and I can’t send you pictures.
I regret to have started this topic not being in my home and I appologize. As soon I will be at home, I send some pictures.
Thank you for your interest.
Hello
Back to my home. Sorry for the wait.
Here, you can see my shield mounting on 2 pictures.
The first picture shows the shield on a UNO R3. It works very good.
The second picture shows the shield on a UNO R4 WiFi. It don’t work. There is an incompatibility between the shield and the PC’s recognition of the UNO R4 WiFi.
But if I download the program onto the UNO R4 WiFi by itself, without the shield, then I put the shield back on, and then the program works.
That is strange, and I have not yet been able to reproduce the problem here. Could you post some close-up pictures of both sides of the Dual G2 High-Power Motor Driver Shield? Also, could you try using a different USB cable and/or port to see if the behavior changes at all?
Brandon
Hello.
It works! I don’t know what to say. I’m so sorry to have taken up your time.
What did I do wrong? I don’t know! I followed your advice and used a different port, USB-A. It worked right away. Then I tried another USB-C port, and it worked perfectly. But I think I had already done that.
The only difference is that I installed the latest Arduino IDE update, version 2.3.9.
To be forgiven, here are some pictures and my trick for separating the shield from the UNO to prevent any contact. My idea is to use spacers. This spacers are made from connectors. I’ve attached some pictures.
In my defense, I think I’ve shown that your shield works with an UNO R4 WiFi. Which is an excellent news.
Here is my project.
I’m not sure what could have been causing the problem either, but I’m glad to hear it is working now!
Your project looks awesome; you might consider sharing more about it on the Share Your Projects section of the forum once it is finished. I’d love to see it in action!
Brandon
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Of course, I will share my project in the Share Your Projects section.
My dream is nothing less than to build an electric car. It’s going to take me a long time… But I promise, I’ll post the result here once it’s finished.
I have a YouTube channel. If you’re interested, you can see my work by searching for Oracid.
Thanks for everything.
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Thank you for your help.
I downloaded the library on April 20, 2026, from this address: https://github.com/pololu/dual-g2-high-power-motor-shield/tree/master
Today, June 8, 2026, on GitHub, in the README.md file, I can see: Version: 2.0.0 Release Date: 2018-04-11
This is exactly the same as the files on my PC.
Following your advice, I tried removing the ARDVIN jumper. Nothing works anymore. So I repositioned the jumper.
Anyway, as I said earlier, things have worked out and for now, everything is fine.
Thank you again for your attention.
Actually, I don’t want to use the power supply through the USB connector.
As I mentioned earlier, I’m using the latest library available on GitHub.
Thank you for your attention.