Ammonia Gas Sensor - MQ-137 Spedizione:2-4 Settimane This pin is pulled low

This pin is pulled low through an on-board 20 k&ohm

A multiplexer/Mux is required to communicate to multiple XA1110 sensors on a single bus

There you go

Is your I 2 C bus not ACK'ing the way you expect

Ammonia Gas Sensor - MQ-137 Spedizione:2-4 Settimane This pin is pulled lowThe MQ 137 is an Ammonia (NH) gas sensor from Winsen. The sensing element is SnO2, which has lower conductivity in clean air. When NH (Ammonia) gas exists, the sensors conductivity gets higher along with the gas concentration rising. A simple circuit makes measuring this change in conductivity and turning it into data fairly straight forward, but does require some calibration. For easy Solderability; use our [Gas Sensor Breakout Board](https: www.