AirElixir --- Sensor data collector on Raspberry Pi

The AirElixir is a sensor data collector on Raspberry Pi, capable of recording and uploading information about temperature, humidity, particulate matters, total volatile organic compound, and equivalent calculated carbon-dioxide to the internet.

Electronic components (sensor)

component	manufacture	matters
DHT11	Aosong	temperature, humidity
SDS021	Nova	PM2.5, PM10
CCS811	ams	TVOC, eCO2

Sensor installation

DHT11

1. Sensor to Raspberry Pi connection

   GND  <-> GND
   DATA <-> Pin 16
   VCC  <-> 3.3V
   

SDS021: edit the system file for using the serial port

1. Edit file /boot.cmdline.txt, delete a characters console=ttyAMA0,115200

   BEFORE: dwc_otg.lpm_enable=0 console=ttyAMA0,115200 kgdboc=ttyAMA0,115200 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait
   AFTER:  dwc_otg.lpm_enable=0 kgdboc=ttyAMA0,115200 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait
   

2. Edit file /etc/inittab, coment the last line of the file

   # T0:23:respawn:/sbin/getty -L ttyAMA0 115200 vt100
   

3. Sensor to Raspberry Pi connection

   Red wire    <-> Pin 4
   Black wire  <-> Pin 6
   Yellow wire <-> Pin 8
   Blue wire   <-> Pin 10
   

CCS811: edit the system files for using I2C

1. Enable I2C

   sudo raspi-config

2. Edit file /boot/config.txt, add to tail

   dtparam=i2c_baudrate=10000

3. Sensor to Raspberry Pi connection

   VCC     <-> 3.3V
   GND     <-> GND
   I2C SDA <-> pin 2
   I2C SCL <-> pin 3
   WAK     <-> GND
   

4. Check that the sensor is wired up correctly

   sudo i2cdetect -y 1

Code installation

git clone https://github.com/nabinno/air_elixir
cd air_elixir
mix deps.get
MIX_ENV=prod mix
GSS_VALUES_APPEND_WEBHOOK={{google-spreadsheets-values-append-webhook}} \
  MIX_ENV=prod \
  nohup elixir --name app@hostname --cookie "AirElixirCookie" -S mix run --no-compile --no-halt &
disown %1

---

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request

EPILOGUE

A whale!
Down it goes, and more, and more
Up goes its tail!

-Buson Yosa