Sensor tests Amsterdam - Dec 17th 2011

MG811 CO2 sensor:
- Setup: 6V over heater; A-B connection to GND and Analog0 pin (Arduino board)
- SW: AnalogReadSerial standard Sketch
- Result: 250mV measured over A-B; Which would mean around 30.000 ppm
- Improvement: Add OpAmp for higher input resistance; Add onboard 6V supply

MH-Z14 CO2 Module
- PWM signal seems to work the best and have the most resolution
- response time is less than 30 s
- 3 minute warm up time
- Seems to need extra power - works when laptop is plugged in, not when working on battery power.

MQ-2 CH4 Sensor
- 24 hour warm up time
- need to solder extra wire to access analog output

Code for MH-Z14 CO2 and MQ-2 CH4 Sensor

Data from MH-Z14 CO2 and MQ-2 CH4 Sensor, tested outside using moped and bus exhaust

From Jeff De Sadelaer, Job Joossen, Ivo van den Maagdenberg,

DHT11 sensor for temp & humidity (DFROBOT) & LPG GAS SENSOR MODULE (MQ-5)
Parallax LPG gas sensor


comparison DHT11 sensor with professional device

Debug logging:

save: /save/1/20/48

save: /save/2/18/50

sensor1 (DHT11): 48% 20°C

sensor2 (DHT11): 50% 18°C

professional device: 57% 19,8 °C