Im developing a project for a Grove temp/humidity/co2 sensor and WIO for Azure.
The two devices will be 2-4 metres apart, which makes them unsuitable because of the I2C cable length limits.
What would you suggest to get around this issue?
I was thinking perhaps a grove RJ45 adapter and CAT6? https://www.seeedstudio.com/Grove-RJ45-Adapter.html ,But I dont know what the max cable length of the RJ45 solution would afford me. It would only be the twisted pair wiring reducing the line capacitance right?
Or perhaps a wifi sender on the back of the env sensor?
Hi Anthony, the seeed studio one looks like simple connector adapter. It might well do it for you, though you also might be better off with an active signal booster/extender. Adafruit make one, and Spakfun have their QwiicBus modules that boost the signal voltage quite a bit (though they are out of stock so they may be waiting on parts).
Just note that the limits can also be stretched a bit, if you vary the resistance of the pullups(with some soldering) you can get some pretty decent performance out of some normal wire. If you have your wire already, a multimeter will let you measure the capacitance. From there you can calculate the correct pullup resistance (download to the I2C spec document)
On the back R1, R2 and R3 look to play some part in pulling up the bus, youll need to probe around to find which one to change though.
If you already have a wireless node can you bring the MCU to the sensor? ESP32’s are really nice boards although theyre a bit harder to use than say a Pico or Uno. Esp32 Australia
Thank you for the quick replies gents, appreciate it. Those are some good suggestions and its making me re-think the design and consider some sparkfun options instead. Reliability and scalability are key factors.
