121 I/O error and no movements (PiArm)

I am trying to get my PiArm working, i assemble it and install the ezblock img on the SD card as the guides, but the arm is not moving following orders from joystick, nor examples from ezblock mobile application which shows 121 I/O error, but sound programs are running normally…
update: when using the screwdriver and touch the pins as shown in the video below it works randomly…

find demo in this video: VID20240410160406.mp4 - Google Drive

You have installed the ezblock OS image system, you also need to install the ezblock studio APP on your mobile device, use the APP to connect to the Piarm product, and use the APP to control the Piarm working.

Install EzBlock Studio tutorial link:


Tutorial for connecting Piarm product with APP:


Yes, i have done that already, the sound examples work fine, but when it comes to movement examples i am getting 121 I/O error in the debug popup.

And also normally it should also work without the app, by just using the joystick as in the assembling video

Please send us a video recording of the sample process you ran. And provide us the screenshot of the error report after running.
Record ezblock APP running the example.
Do you get the same situation when you run other examples.
Please check if there is something wrong with your assembly.
The first thing to do is to do servo adjustment back to zero before assembling the fixed servo.
1、First start the robot and wait for power on, if you hear a loud sound, it means the robot is successfully turned on.
2, will upset the angle of the servo, connected to the p11 foot lead
3, and then hold down the USR key do not let go, and then press the zero RST key, you can wait for the servo back to zero. (Hint: before the servo does not return to zero, hold down the USR key and do not let go)
When the servo return to zero successfully, then assemble the servo arm fixed, and so on until all servo return to zero assembly completed.
In the absence of an application program, it is not possible to use the joystick to control the robot arm, oh, you need to run the sample code to control.