Qwiic is SparkFun’s easy-connect ecosystem for I2C devices. I wanted to play with some I2C temperature sensors with a Raspberry Pi so I thought I would give Qwiic a try. The simplest and least expensive way to start with Qwiic on a Raspberry Pi is the Qwiic shim. The Qwiic shim is a small board with through holes that is pushed onto the appropriate RPi GPIO pins. The shim is meant to sort of wedge onto the pins and make electrical contact while leaving the pins free for connecting other wiring or devices.
Unfortunately, the shim doesn’t always make contact on all the pins which means your I2C connections won’t work. There were a lot of complaints about this in the reviews at Sparkfun’s web site. Some people solved the problem by soldering the the shim to the GPIO pins, which is somewhat antithetical to the spirit of the shim. Others ben the pins to get better contact.
I decided to jam something between the rows of pins which worked well. I started with a USB charging cable of appropriate thickness, which worked. I settled with a small roll of paper (see photo). On the second day the paper had compressed to the extent that the shim was no longer working so I added a few more layers of paper. It’s been like that for 6 or 8 months and is still working fine.