dht22-rpi

pigpio and Python code (class Sensor) taken from http://abyz.me.uk/rpi/pigpio/index.html

Notes

Tested on an RPi 4 4GB running Hypriot with an AM2032 sensor, YMMV. While this will compile on amd64/x86, pigpio will not run.

You'll need to bump gpu_mem in /config/boot.txt up past 16 MB in order for Docker to have enough to allocate; I used 64 MB.

If you get initMboxBlock: init mbox zaps failed and you've already raised the gpu_mem up, try restarting your Pi.

You also need to run it in privileged mode to get access to GPIO. If you know of a better way, please let me know.

Build and run instructions

Python

$ python DHT22.py

Docker

$ docker build -t $YOUR_TAG .

or

$ docker pull stephangarland/rpi-dht22:latest

then

$ docker run -d --privileged -v /path/on/host:/home/log -e file='$FILENAME.log' $YOUR_TAG

Usage / Options

Args are below, defaults are as follows:

• temp: F
• interval: 300
• gpio: 5
• lower: 40
• upper: 100
• warn: True
• pushbullet: None

Python

$ python DHT22.py --help
usage: DHT22 [-h] [-t {C,F,K,R}] [-i INTERVAL] [-g GPIO] [-f FILE] [-l LOWER]
             [-u UPPER] [-w WARN] [-p PUSHBULLET]

Parse the output of a DHT22 sensor

optional arguments:
  -h, --help            show this help message and exit
  -t {C,F,K,R}, --temp {C,F,K,R}
                        Unit for temperature
  -i INTERVAL, --interval INTERVAL
                        Interval between logging in seconds
  -g GPIO, --gpio GPIO  GPIO pin sensor is connected to
  -f FILE, --file FILE  Path to logfile
  -l LOWER, --lower LOWER
                        Lower limit (F) to alert at
  -u UPPER, --upper UPPER
                        Upper limit (F) to alert at
  -w WARN, --warn WARN  Enable warnings in logs
  -p PUSHBULLET, --pushbullet PUSHBULLET
                        API key for Pushbullet

Docker

Pass desired long-form args from above as environment variables as seen in the run example, using -e file=... Don't forget to include -e TZ $YOUR_TZ per the tzdb format.