Issues with Qwiic Shim, Keypad, SerLCD

Qwiic System
1

I just purchased a Qwiic Shim, Qwiic keypad, and Qwiic SerLCD to use in a project, as well as two Qwiic cables. The shim fits snugly on my Pi Zero WH, but I’m having some issues.

On the screen:

The screen works with the sample (Python) code and for the most part behaves as expected. However, when I pick up/move the LCD, random characters get filled in solid black and the cursor sometimes loses position (picking a new position, seemingly at random). I suspect there is something loose somewhere, but I cannot figure out where or what. I’ve tried this with both cables.

On the Keypad:

With the sample code, key presses often (but not always) record as empty boxes or a ÿ (y with an umlaut). Quickly this fails with an error - “OSError: [Errno 121] Remote I/O error”. I’ve tried both cables and without the screen connected. This seems to be like a communication issue that results in corrupted characters received by the Pi.

I’m guessing these are related issues. Does anyone have any tips or suggestions?

2

Do you perhaps have another Pi you could try the products on?

Both cables and both products (LCD/keypad) showing issues might point toward the board itself either having something loose or a configuration issue of some kind

3

The random characters you’re seeing when you pickup the LCD are coming from electrical noise from your body getting into the RX pin on your display. You could try connecting the RX pin to “+” on the FTDI header with a 10K resistor to see if that helps eliminate the issue.