I have built the pi dog again very carefully, however, when I run the zeroing script after all legs are installed, one of the legs is wonky again.
Can you give me troubleshooting advice as to how to fix the one leg given that alot of parts are already connected? Please see photo. Thanks.
OK, I got that leg fixed. No need to answer that question. But now one of the left legs trembles when I zero. Does that matter, do I have to fix that? It doesn’t tremble when I’m not zeroing. I think I need to go find some remedial reading on servos and zeroing.
Thanks for any info you can provide.
It seems the issue may be due to not correctly centering and securing the servo during assembly. This can cause the servo to exceed its angle limits when running the zeroing example, resulting in jitter or locking up.
The servo angle range is -90° to 90°, but the factory-set angle is random (often 0° or 45°). If assembled with these angles directly, it can lead to chaos during operation and may even damage the servo.
To properly set all servo angles to 0° before installation, please follow these steps:
- Insert the servo arm onto the servo shaft and gently rotate it to ensure it moves.
- Run the servo zeroing code:
cd ~/pidog/examples
sudo python3 servo_zeroing.py
- Connect the servo wire to port P11, and you should see the arm move to the 0° position.
- Remove the servo arm while keeping the wire connected to P11, and do not turn off the power. Continue assembling as per the instructions.
I recommend watching our assembly videos for guidance, particularly the parts on setting the servo to zero:
This is a jerk reply. Like the poster above, my dog is all messed up. Your advice to go back in time and not have it zero’d incorrectly is completely worthless. It translates to you shouldn’t have screwed up.
This is the same advice given throughout the many times this issue has been brought up. A reasonable engineer or technical writer would recognize a common issue as a flaw in the instructions.
Also, maybe people don’t want to watch the videos. If the written documentation is not significant, why do you include it?
I am amazed how little your company cares about its customers.
Mkrummel, The printed assembly booklet we provided has clear assembly steps. However, if any details are missed, it may lead to assembly errors.
In the case of Blancabasura, the issue was that the servos were fixed without performing a zeroing adjustment, which caused inconsistencies in the servo angles when running the PiDog after assembly. The only solution at this point is to disassemble and reinstall the servos.
Of course, if there are any issues with the printed assembly booklet, please let us know your suggestions. We welcome feedback to improve the assembly instructions for everyone’s benefit.
We also provide assembly videos to help those who encounter problems during assembly. Watching the videos can help identify and correct issues more intuitively. Additionally, if there are shortcomings in the printed booklet, we appreciate any valuable feedback you can provide.
So I just finished assembly. One side is fine. The other side is no matter what I do….when I run that calibrationRx…..the bad side KEEPS going to like 120degrees instead of 60!!!
I think the founder is correct….you have to restart servo assembly AGAIN!!! I am going to attempt tonight….!
That’s the 120degrees I was taking about 
Yes, if the servo is heating up, it is very likely that it is stuck or jammed. Please try the following steps:
Remove the servo from the leg assembly.
Press the ZERO button on the Robot HAT (you may press it a few times to ensure it registers).
Reattach the servo at a 90° angle as per the assembly instructions.
This should help resolve the issue. Good luck, and let me know if you need further assistance.
Okay! That was FAST, Sunfounder. Thanks. I am attempting Now. I should record the video. I want this thing ready for Father’s Day
I guess my question is……
I did what you said. I keep him on. I pull off the thighs. I push Zero….several times. Then, I manually hang the thighs at 90. Now what?’ Bc he is still on, and so…..should I go run a Rx??? Maybe calibration? See if he goes back to 120 again??? Should I now shut it off immediately after installing those thighs? I am going to play with this thing and try and bunch of methods….but I look forward to an answer. Thanks
That’s frustrating!!! I did what was requested. And I then immediately ran my Calibration Rx. And guess what??? The little guy went back to 120 on the bad side? Why does he recognize 90 just fine….but he can’t do 60 only on one side??? It is so frustrating. No matter what I do or try….these legs are stuck at 120??? Even after several rewrites??? And when I run the calibration as if I had a 90ruler….i was given a 60degrees ruler in my PiDog……but when I run the 90….he is able to go to 90! But he can’t do 60 but the one side???
Thank you for your patience, and I apologize for the slow reply.
We actually recorded a video for you showing how to remove the leg and reattach it properly. But while reviewing your issue again, I suddenly realized that the 60° and 120° angle mismatch may not be an assembly error at all – it could be something much simpler: the servo wiring on the left and right sides might be swapped!
Think about it – the left and right servos are symmetric. When they are both supposed to move forward or backward, one side should increase its angle while the other decreases. If the cables are reversed, they would move in the wrong directions.
Could you please send me a photo of your calibration when you set the leg to 60°?
Here’s what I recommend:
Please follow the assembly instructions carefully and re‑insert each servo cable one by one.
For example:
Run the calibration program and set the leg to 60° (keep the program running).
Insert the left rear thigh servo into P0 and check whether it is in the correct position.
Then insert the left rear calf servo into P1.
I’m very sorry I didn’t think of this sooner, so that you missed having it ready by Father’s Day. But we still have time to get it right – I will follow this issue through until it is completely resolved.
Here is the video showing how to remove and reattach the servo leg on the PiDog.https://youtu.be/9ddLDdHvmuo
Although you may not be facing the exact issue, we hope this video is helpful for anyone else who might need it.