Temperature sensor server for Orange Pi (Lite)

This service reads temperature and humidity data from the popular DHT22 (or DHT11) and DS18B20 sensors connected to an OrangePi board. The measured data is then accessible as JSON string by querying the embedded HTTP server.

You should modify the source code of this server to suit your needs as the current configuration is tailored to my specific needs.

Requirements

libevhtp-dev
libevent-dev
wiringOP (https://github.com/zhaolei/WiringOP)

You should be install the libraries using apt-get eg. (apt-get install libevhtp-dev), check the link for wiringOP.

Sensors

I'm using the DS18B20 for outdoor and the DHT22 for indoor measurements. If you are using only one sensor then you should modify main.c to suite your needs (json_response, update_thread, etc).

DHT22

Connect the sensor to the board, in my case I used Pin 7 (PA6) on the GPIO header for the data line. Modify DHT_PIN in dht22.c if you are using a different port.

DS18B20

Enable 1-wire support on the board using armbian-config if you are using Armbian. Connect the sensor to Pin 37 (PA20) on OrangePi Lite (check the corrent port for other variants). Don't forget to add param_w1_pin=PA20 to /boot/armbianEnv.txt! After reboot you should list the recognized 1-wire devices with ls /sys/bus/w1/devices/ and update w1_sensor_id in main.c.

Building

Use make. If it succeeds then the binary will be in the .build folder.

Running

Run temp-montor as root (with sudo).

Querying

Send an HTTP GET request to http://IP:8012/sensor. For example use curl:

curl http://127.0.0.1:8012/sensor

If the server is working correctly then it should respond with a JSON resonse like this:

{
  "sensors": {
    "dht22": {
      "temperature": 25.1,
      "humidity": 44.5
    },
    "ds18b20": {
      "temperature": 19.2
    }
  },
  "updated": "2018-07-03T23:08:40Z"
}

Values are in Celsius.

License

MIT.

kiwep / temp-monitor