Sensors to consider!

A project log for conscientious koala

Let's get an open-source sensor toolkit that can be used by communities to detect forest fires as early as possible!

neil-k-sheridanNeil K. Sheridan 05/18/2022 at 19:170 Comments

To note with these gas sensors: we'd want a fan to get good ambient air flow into the enclosure containing the sensors!

PM 2.5

Nova PM Sensor SDS011 (0.3 to 10μm)  only rated 70% humidity | PRICE: approx £18 // some accuracy comparisons


First we want to know what level of C02 should we expect normally for baseline? Well sea level at 15 C and 101325 Pa [verify source!] we have 0.04% C02 in the air.

The EM500-CO2 CO2/Temp/Humidity/Pressure Sensor is popular for forest fire applications, however it costs around 250 euros! So that's no good!

These are all kinda expensive. We've got maybe the MG811 "gives an output in the range of 100-600mV (400—10000ppm CO2)" 400ppm being the baseline CO2 in air. Or perhaps MH-Z16 which is similar. These are in price range of $40-70


Something like the DHT22 which can also do humidity | PRICE $3-4


We've got something like the 'Gravity: Analog Capacitive Soil Moisture Sensor- Corrosion Resistant' sensor for around £6


I'm thinking of these or similar I2S MEMS Microphone for Raspberry Pi (INMP441) for around $8


Well if we do use a raspberry pi then we can use the standard camera 16MP fixed focus for £30 and do a detection of smoke or non-smoke images! Cost is around £30. An alternative is a thermal camera such as MLX90640 Thermal Camera (I2C) which sounds quite interesting. But we have a pricing of $90 and very small numbers available for supply.


Besides the camera, we seem to be looking at around $80 for sensors. The C02 sensors being most expensive, since these are electrochemical. However, there are some NDIR (nondispersive infrared) sensors that can be used. Although I envisage these to be more costly. The MH-Z16 is actually NDIR and slightly more costly. But we will need to further investigate these C02 sensors.

I'm not really feeling very hopeful to get to under $200 when we add an MCU + board and comms + power!