SensorPi

A Raspberry Pi Zero W temperature and humidity sensor which logs to Postgres via GET requests

Hardware

• Raspberry Pi Zero W
• SEN-DHT22 Sensor (Joy-IT, integrated resistor, 1-wire protocol)

Software

• Raspberry OS (Buster, 01-11-2021)
• Python 3.7
• pigpiod
• a DB server which accepts the GET requests! (not included here, implement e.g. with this tutorial)

Preparing the board

• "burn" the iso file onto an SD card
• add an empty file called ssh (without extension) into the boot partition
• add the configuration file wpa_supplicant.conf for the WIFI connectivity to the boot partition (needs Linux line endings! Use Notepad++ to ensure this!):

country=DE 
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev 
update_config=1 
network={
     ssid="WLAN SSID"
     scan_ssid=1
     psk="WLAN PASSWORT"
     key_mgmt=WPA-PSK
}

• put the SD card into the RasPi and connect the DHT sensor as shown to pins 3v3, GPIO4, GND
• boot the Pi and SSH in
• then run passwd for pi user and sudo passwd for su user
• then run sudo raspi-config to set locale, hostname, enable Pin IO and I2C. (GUI can be turned off)
• reboot
• give static IP adress via options in the router (leave the Pi on DHCP mode)
• update the system and go drink some coffee

sudo apt-get update
sudo apt-get upgrade

Preparing the program

First, we get everything from github.com

mkdir sensorpi
cd sensorpi
git clone https://github.com/GSAVV/SensorPi.git
sudo chmod +x startup.sh

Then, we install the dependencies

sudo pip3 install pigpio-dht

After that, we set the connection details of the PG server inside the sensorpi.py script

Finally, we add the following line to the /etc/rc.local file

/home/pi/sensorpi/startup.sh &