Circuit Playground Express (CPX) + Crickit + I2C sensors

Question

I have a Circuit Playground Express (CPX) mounted on a Crickit. I want to control two air pumps using the motor output on the Crickit, but also connect two Adafruit SCD41 sensors using I2C.

When I connect the SCD41 to the CPX without the Crickit, it works. When I do the same with the CPX mounted on the Crickit, it does not work.

I assume this has something to do with the Crickit "occupying" the I2C-bus.

I also have a TCA9548A I2C multiplexer, but I'm not sure if this will help me, or how to use it. Should I connect the multiplexer to the CPX, and have the Crickit and the two sensors connected as multiplexed devices?

How to proceed?

• jsotola: I assume this has something to do with the Crickit "occupying" the I2C-bus. ... do not assume anything, make certain
• LuxNo: @jsotola: Fair enough, but I don't know how to make certain, so I'll ask: Will the Crickit block other devices from using I2C? I tried using the TCA9548A I2C multiplexer, but I'm getting an error "OSError: [Errno 5] Input/output error". So I'm not sure what to try next.
• jsotola: run an I2C scanner program to determine which addresses are being used ... that will tell you if there is a conflict between devices
• LuxNo: Thank you. First I tried with only Crickit connected. It returned address 0x49, which makes sense. This is the Crickit board. Next I connected the I2C multiplexer to the same SDA and SCL that the Crickit board uses, and now read '0x49', '0x70'. 70 is the multiplexer so this is good. However, now my issues begin. In order to access the devices connected to the multiplexer I do this: tca = adafruit_tca9548a.TCA9548A(i2c) followed by tca[0].try_lock(), but this causes the error OSError: [Errno 5] Input/output error