Sensing station project on Raspberry Pi. The project is divided into
software and hardware. The software parts consist of 3 main bits:
daemon called mqtt_rpi which runs on raspberry Pi and is used to
send statistics. Application called mqtt_channel used to collect
sent statistcs. And the plotting software which are basically shell/python
scripts. The hardware part includes board designs as well as designs of 3D
printed parts (n/a yet). Everything works via MQTT protocol. An example
of MQTT client is available in
The standard installation assumes that You have an access to MQTT broker and a VPS or something like that to collect the statistics. Since I use rrdtool as a plotting library the statistics require continuity. You should provide a stable connection with accetable latency (can't be too slow). It is not recommended to run mqtt_channel on the same raspberry Pi where You run mqtt_rpi because of SD card overload (It could simply kill Your SD card).
mqtt_rpi is a broker client as all software pieces written here. it sends statistics from previously configured gpios/i2c devices specified in a config file mqtt_rpi.yaml. Also it handles some basic commands including relay switch on and off.
Normally it is supposed to be invoked via startscript placed in /etc/init.d/pigoda
It has few useful command line options described below.
-V Prints build date and time usage() information and then exits with exit(2) code EX_USAGE.
-c Path to config file. If not defined defaults to /etc/mqtt_rpi.yaml
-v Verbose mode. (not implemented yet)
-d Debug mode. (Ditto)
-f Stay in foreground
An example config file included below:
%YAML 1.1
---
pidfile: "/var/run/mqtt_rpi.pid"
logfile: "/var/log/mqtt_rpi.log"
debug: 4
daemon: false
delay: 5000000
identity: "mrpi_pooler"
mqtt_host: "localhost"
mqtt_port: 1883
mqtt_user: "mqtt_rpi"
mqtt_password: "CHANGE_ME"
mqtt_keepalive: 120
# configuration of channels
sensors:
- name: "tempin"
type: "ds18b20"
address: "28-00000XXXXXXX"
channel: "/environment/tempin"
- name: "tempout"
type: "ds18b20"
address: "28-0000XXXXXXXX"
channel: "/environment/tempout"
- name: "pressure"
type: "i2c"
i2ctype: "bmp85"
channel: "/environment/pressure"
- name: "light"
type: "i2c"
i2ctype: "pcf8591"
address: "0x48"
config: "0"
channel: "/environment/light"
gpio:
- name: "green_led"
gpio_pin: 2
type: "failure"
- name: "red_led"
gpio_pin: 0
type: "notify"
- name: "pir_case"
gpio_pin: 6
type: "pir_sensor"
- name: "power button"
type: "pwr_btn"
gpio_pin: 5
...
Let's describe first set and meaning of system related variables
| Variable name | Possible values | Description |
|---|---|---|
| pidfile | STRING | Includes a valid path in *NIX like system. Defaults to > /var/run/mqtt_rpi.pid |
| logfile | STRING | Defaults to "/var/log/mqtt_rpi.log" |
| debug | NUMERIC | When greater than 0 activates extra debug messages |
| daemon | BOOL | daemon mode |
| delay | NUMERIC | Defines delay in a pooling loop. Defaults to 5000000 |
Other variables are related to MQTT connection, like identity user and password used to authenticate on a remote mqtt_host
| Variable name | Possible values | Description |
|---|---|---|
| identity | STRING | Change this variable in case of having more than one station. |
| mqtt_host | STRING | A valid FQDN address for MQTT broker. Defaults to "localhost". |
| mqtt_port | NUMERIC | Port number. Defaults to /1883/. |
| mqtt_user | STRING | User name used to authenticate the client. |
| mqtt_password | STRING | Password. |
| mqtt_keepalive | NUMERIC | Delay between keep alive probes |
Ready to use version is available. However it's missing some documentation
| Part | Task | Priority | Status |
|---|---|---|---|
| mqtt_rpi, mqtt_channel | Reconnecting on MQTT error | - | Done |
| mqtt_rf | Need to integrate with mqtt_rpi | High | Not started |
| mqtt_pir | Need to integrate with mqtt_rpi | - | Done |
| new pigoda v2 board | redesign, include more gpio protection (with optocoupler and or overcurrent protection) | High | design ongoing |
| website | Make a simple responsive website | High | In progress |
| mqtt_channel | Change database engine to MySQL from Sqlite3 | Medium | Not started |
| mqtt_channel | code checkout | Low | Not started |
| 3D models | Models for boxes used to isolate sensors etc. | Low | Not started |
The basic knowledge about MQTT protocol is required More info on https://github.com/mqtt/mqtt.github.io/wiki
There are 4 applications:
- mqtt_rpi - Gets the data from sensors, process it, and publish on a given MQTT channel.
- mqtt_channel - Listens on a given channel and stores the obtained data to Sqlite3 database.
- mqtt_rf - Gets statistics from nRF24+ and pushish it on a given MQTT channel.
Download the source repository, compile* the sources and install it:
git clone https://github.com/jezpi/pigoda
cd mqtt_rpi
make && make install
there are some dependencies like libyaml libmosquitto libsqlite3 and libbsd The application is located in /usr/bin/mqtt_rpi. It installs the configuration file placed in /etc/mqtt_rpi.yaml. The syntax is a YAML syntax. You need a MQTT server which defaults to 172.17.17.4, change it to Your server. You have to configure daemon mode in /etc/mqtt_rpi.yaml ( mqtt_rpi does not detach from terminal by default and it prints loads of debug messages) like this:
daemon: true
Ready to use/develop version is available and there's no documentation
Working version available
Ready to use/develop version is available
Under development (Proof of concept version already works and stores data into db, however the code needs to be polished a bit)
In a directory eagle of github repository there are available boards designs ready to fabricate. The width of connections is thick on purpose. More information will be available soon.
It takes 58seconds to start rpi 350mA while it's running and ~400mA on a startup