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I2C communication between MCU and sensor with few meters distance

Question asked by Andreas Hansen on Nov 29, 2016
Latest reply on Nov 29, 2016 by Jacques Trichet

Hi,


In short, what I try to achieve is to connect a sensor to a MCU via I2C where the distance between the two is in the range 2-3 meters. I want to do this in the cheapest and simplest way i.e. with as little added hardware as possible. I'm considering the approach illustrated in the attached image where I both feed the sensor with power and SDA/SCL wires in a single cable. The sensor draws 1.25 mA during conversion. The only component that is put at the sensor-side is a decoupling capacitor of 100 nF. At the MCU-side I intend to place two pull-up resistors of 10k.

 

I'm aware that I2C is made for inter-circuit communication (probably with distances in the cm-range), but how far is it possible to stretch the distance without facing too many issues due to noise and too much capacitance caused by the long wires. I'm not a very experienced hardware designer (which my circuit might show) so I would like to hear your recommendations and experiences with this.

 

Best Regards,
Andreas

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