Dear all,
I recently bought a Differential I2C Bus Extender to connect my flowmeter SFM3000 from Sensirion to a fairly distant (5 meters) ESP32 board. The flowmeter workds perfectly when connected without the Extender, but when I connect it through the cat 6 cable I get readings that are not plausible. I am quite sure that the problem is related to the voltage that needs to be supplied to the extender, as my flowmeters works at 5 V. How should I handle this on both sides of the cable? Should I go for 3 volts for the board and 5 to the flowmeter?
Thanks for your support guys!
Even though Qwiic boards are typically 3.3 volt only, this particular board will work at 5 volts. If you do run it at 5 volts, just don’t attach any 3.3 volt Qwiic parts to it or you can damage those. You can also put a separate power supply on the local board and have it pop out on the remote but you do need to change a jumper to do that. See the [hookup guide for more information on making those changes.](Qwiic Differential I2C Bus Extender (PCA9615) Hookup Guide - SparkFun Learn)
Thanks for your prompt response. This means that I can simply hook the sensor through the board as if it was directly connected to the ESP32, leaving the RJ45 cable deliver the power, without changing any jumper, am I right?
You will need to change jumpers, the hookup guide has the details on what needs to be changed.