Air Quality Sensor. Can't enable polling mode
dave 2017-08-05 23:26:54 983 Views1 Replies I cannot enable polling mode on the new PM2.5 Air Quality sensor. When I check the RX line at the DFRobot interface board and the actual RX line at the connector to the sensor, there is a voltage offset and it never goes to zero and is about midway. The RX LED is always ON too. It flashes to off when data appears on the RX line.
See the attached capture from the scope. The yellow line is the RX output to the sensor and the blue line is the RX input to the board (also direct line from the ESP8266)
It looks like the LED is inserted the wrong way around but as there is no schematic for this board, I am unable to check this.
See the attached capture from the scope. The yellow line is the RX output to the sensor and the blue line is the RX input to the board (also direct line from the ESP8266)
It looks like the LED is inserted the wrong way around but as there is no schematic for this board, I am unable to check this.
DS2_QuickPrint5.png Download(0) 2017-08-05 23:30:38 As a test, I removed the resistor to the LED and now the signal levels are good and I can enable to poll the data.
Handy if anyone else runs into this issue. dave
Handy if anyone else runs into this issue.
dave 