P.Sens: a CO2 Sensor

In order to make a CO2 sensor, we used a CJMCU-811 CCS811 gas sensor connected to an Arduino microcontroller. The data was then sent via bluetooth to the android app. We used MIT app inventor to program our app. This is a very quick and efficient way of writing simple apps like ours; especially if you don't have a lot of programming experience.

Connecting the gas sensor: connect sensor board’s SDA to A4 and SCL to A5 pin of Arduino board. Then connect 3.3V pin to Arduino 3.3V pin and Gnd to Gnd pin of Arduino.

Connecting the bluetooth: connect the Rx on the bluetooth to theTx pin on Arduino and the Tx pin of the bluetooth to Rx pin of Arduino. Then connect the 5v to +5v pin of Arduino and GND pin to GND pin.

First of all, download Adafruit_CCS811 library on arduino and install it. Then Open the CCS811_test example by going to File -->Examples -->Adafruit_CCS81 and upload it to your board; the sensor will start to take measures. We changed the program so it would only show the readings of CO2 in ppm.

The MIT app inventor is a great tool for writing simple apps in a short time. Go to their website and make an account to write your app. App Inventor contains the Designer and the Blocks Editor. The Designer lets you design the app interface; the blocks lets you program your functions by putting blocks together. You can find the designer features we used as well as the blocks in the photos attached.

The photos might not be clear on here so we attached a PDF of all the steps that you can download. Hope you find this useful!