piwatcher

The purpose of this project is to build an array of Raspberry Pi Zero nodes, equiped with BMP280 temperature sensors, for home automation.

These headless nodes collect (near) real-time temperature and pressure data, and push them to an ElasticSearch node.

Current status : completely experimental !

BMP280 i2c driver code comes from SunFounder SensorKit.

Thanks guys for this great work !

Requirements and Installing

apt-get install python3-rpi.gpio python3-smbus python3-elasticsearch python3-redis pip3 install hbmqtt modprobe i2c_dev

python3-daemonize may be helpfull in the future...

The install.sh script is a convenient way to deploy what's required, with all nodes keeping their configurations under git as well.

Still having trouble finding out the 'python3' way to deploy packages on the system (aka applications and services), all the code remains in the ~/git/piwatcher directory at the moment (that may change).

Note that accessing i2c bus requires root privilege by default, so piwatcher is run as root here (there may be special tricks to do so, didn't spend time on it yet).

Configuring

Two configuration files are required :

~/piwatcher/config.json : piwatcher configuration itself

Most of the piwatcher behavior can be setup in this JSON-formatted config file. See examples in confs/* to see how it can be set up.

{
    "hostname" : "osmc",
    "disk": {
        "enabled": true,
        "ledPinout": 11,
        "deviceName": "sda"
    },
    "sensors" : {
        "bmp280" : {
            "enabled": true
        }
    },
    "elastic" : {
        "hosts":[{"host" : "osmc"}],
        "index": "oswh-osmc",
        "type": "sys-measure"
    },
    "stats" : {
        "updateInterval" : 2,
        "statsInterval" : 60
    }
}

/etc/piwatcher-daemon.config : piwatcher service daemon configuration

This config file only deals with running the daemon service properly. Config values are pretty straightforward.

Features

Notation :

• All conf:setting.setting code refers to configuration settings, see Configuring.
• All stats:$host.stats code refers to information pushed to ElasticSearch.

General behavior

Basically, piwatcher will loop each conf:stats.updateInterval seconds and retrieve information. Each conf:stats.statsInterval, it will push this information to ElasticSearch.

CPU monitoring

Monitoring load (aka /proc/loadavg), taking the last-minute value, and pushing it into stats:$host.cpuLoad. CPU temperature is pushed to stats:$host.cpuTemp.

BMP280 Temperature sensor

Temperature is pushed to stats:$host.indoorTemp, pressured is pushed to stats:$host.indoorPressure

Disk monitoring

Disk state is pushed to stats:$host.diskState and can take values standby, idle or active. stats:$host.cumulateDiskStateTime counts the number of seconds the state did not change. That's a float with may too much precision ATM...