BrewBlox Service for the iSpindel Hydrometer

The iSpindel is a DIY wireless hydrometer and thermometer used to gather live readings of specific gravity and temperature when brewing beer.

BrewBlox is a modular brewery control system design to work with the BrewPi controller.

This brewblox service integrates the iSpindel hydrometer into BrewBlox.

How does it work?

The iSpindel is configured to send metrics using HTTP.

When the iSpindel wake up (like every minute) it submits an HTTP POST request to the iSpindel BrewBlox service.

The metrics are then published to the event-bus, the BrewBlox history service persists the metrics into the InfluxDB database.

A Graph widget can be added in the BrewBlox UI to display the persisted metrics.

Usage

Deploy the iSpindel service in the BrewBlox stack

You need to add the service to your existing BrewBlox docker compose file:

  ispindel:
    image: bdelbosc/brewblox-ispindel:rpi-develop
    restart: unless-stopped
    depends_on:
      - history
    ports:
      - "5080:5000"
    labels:
      - "traefik.port=5000"
      - "traefik.frontend.rule=PathPrefix: /ispindel"

The brewblox-ispindel docker images are available on Docker Hub.

The image tag to use is:

• rpi-develop for the arm architecture (when deploying on a RaspberryPi)
• develop for the amd architecture

Note that the service expose an HTTP endpoint on port 5080 this is required because the iSpindel does not handle HTTPS.

Start your BrewBlox stack using brewblox-ctl up.

Check that the service is running:

# Run the docker-compose command from the directory holding the brewblox docker-compose file
$ docker-compose ps ispindel
       Name                     Command              State           Ports
-----------------------------------------------------------------------------------
brewblox_ispindel_1   python3 -m brewblox_ispindel   Up      0.0.0.0:5080->5000/tcp

$ docker-compose logs ispindel
...
ispindel_1   | ======== Running on http://0.0.0.0:5000 ========
...

Configure the iSpindel

First find the IP address of your BrewBlox server then check that: http://IP:5080/ispindel/_service/status replies with a:

{"status": "ok"}

Note that the port must be set according to what is exposed in the docker-compose.yml file (5080 is our case).

Then:

• Switch the iSpindel on
• Press the reset button 3-4 times which sets up an access point
• Connect to the Wifi network "iSpindel"
• Open a browser on http://192.168.4.1
• From the "Configuration" menu, configure the Wifi access, then
  • Service Type: HTTP
    • Token:
    • Server Address: <IP>
    • Server Port: 5080
    • Server URL: /ispindel/ispindel

Double check that your are using an HTTP service type (and not a TCP).

Add a Graph to your dashboard

From your dashboard ACTIONS > New Widget then select and create a Graph widget.

Once the iSpindel has sent some data, you should see its metrics when configuring the widget:

Development

Get started

To get started:

# Add repository containing Python 3.8
sudo add-apt-repository ppa:deadsnakes/ppa

sudo apt install -y python3-pip python3.8 python3.8-dev
pip3 install --user pipenv

# in the brewblox-ispindel directory
pipenv --python 3.8
pipenv sync -d

Run tests

pipenv run pytest

Build a docker image

1. Install the brewblox-tools

2. Go into the brewblox-ispindel directory and build the rpi-latest image

brewblox-dev localbuild -r bdelbosc/brewblox-ispindel --tags latest -a arm

Use -a amd to build the latest image for amd architecture.

Simulate iSpindel request

From the BrewBlox host:

curl -XPOST http://localhost:5080/ispindel/ispindel -d'{"name":"iSpindel000","ID":4974097,"angle":83.49442,"temperature":21.4375,"temp_units":"C","battery":4.035453,"gravity":30.29128,"interval":60,"RSSI":-76}'

# or using https
curl --insecure -XPOST https://localhost/ispindel/ispindel -d'{"name":"iSpindel000","ID":4974097,"angle":83.49442,"temperature":21.4375,"temp_units":"C","battery":4.035453,"gravity":30.29128,"interval":60,"RSSI":-76}'

Check iSpindel service logs

Each time the service receive a request there is a log showing the temperature and gravity. To run from the directory containing the docker-compose.yml file.

docker-compose logs ispindel
...
ispindel_1 | 2019/04/12 14:18:34 INFO __main__ iSpindel iSpindel000, temp: 21.75, gravity: 22.63023
ispindel_1 | 2019/04/12 14:19:05 INFO __main__ iSpindel iSpindel000, temp: 21.6875, gravity: 22.69526

View iSpindel metrics persisted in the influxdb database

To run from the directory containing the docker-compose.yml file.

docker-compose exec influx influx
> USE brewblox
> SHOW SERIES
key
---
iSpindel000 -- This is the name given to the iSpindel
sparkey
spock

> SELECT * FROM "iSpindel000"
name: iSpindel000
time                angle    battery  gravity   rssi temperature
----                -----    -------  -------   ---- -----------
1546121491626257000 83.49442 4.035453 30.29128  -76  21.4375
1546121530861939000 84.41665 4.035453 30.75696  -75  19.125

> -- Latest metrics
> PRECISION rfc3339
> SELECT * FROM "iSpindel000" WHERE time > now() -5m ORDER BY time DESC LIMIT 10
time                         Combined Influx points angle    battery  gravity  rssi temperature
----                        ----------------------- -----    -------  -------  ---- -----------
2019-04-12T14:15:29.715678Z 1                       71.6947  4.233577 22.67045 -68  21.9375
2019-04-12T14:14:58.997279Z 1                       71.58447 4.233577 22.51496 -67  21.9375

Continuous integration pipeline

Using Azure, the pipeline automatically test and deploy all commits pushed on the GitHub repository.

This means that docker images for arm and amd are published on Docker Hub and the python package is deployed on PyPi.

TODO

• Debug mode where the service subscribes to the brewcast channel to debug what is published.
• Support an HTTP token that can be set in the docker-compose file.

Limitations

• There is no security on the iSpindel endpoint