Smart Dispenser: Dispenses solutions based on the VOC
By Dan Chen, September 28, 2017
In this experiment we are dispensing mouthwash, but you can dispense any solution that you like base off your sensor data. This is a close loop control system where the output is based on the sensor data.
In this example, bad breath can be measured via volatile sulfur sensor, however but we are using the TVOC sensor … it’s tracking all VOC compound but can not isolate bad breath compound, sulfur . This sensor will be sufficient for what we are doing. Imagine you can dispense water pairing with humidity sensor, this could give you the right amount of water based on how dry your mouth is … I am not totally sure the science behind this, it’s just an example.
Adafruit Feather M0 Basic Proto – ATSAMD21 Cortex M0
or any micro controller with M0 chip so it’s easier to port my code over https://www.adafruit.com/product/2772
You can download the sketch here, make sure that you include all the right libraries.
https://danchen.me/lab/wp-content/uploads/2017/09/VOC_OLED_Graph2.ino_.zip
Feel free to tweak the software, but in this sketch it work as follow.
Standby State: Measure and display the TVOC level / neopixel reflects the TVOC level
When TVOC level went above the threshold, the neopixel will starts blinking
The user can now place the cup under the distance sensor to activate the pump
The pump will not activate when TVOC is below the threshold (optional)