Tilt Hydrometer

This software is a replacement for TiltPi and posts your Tilt readings straight to Brewfather and/or to a MQTT broker.

It is a Ruby based commandline-tool that is easy to install and works effortless on Linux (Raspberry Pi OS).

Raspberry Pi OS unfortunately ships without Ruby and the hcidump utility, so you first need to install both:

sudo apt-get update
sudo apt-get install ruby bluez-hcidump

Then install the tilt_hydrometer executable via:

sudo gem install tilt_hydrometer

As interacting with the bluetooth device on Raspberry Pi OS requires root-priviliges, start reading and posting to brewfather by using the tilt_hydrometer command with sudo:

sudo tilt_hydrometer -b http://log.brewfather.net/stream?id=abcdefghijkl123

In order to receive any BLE beacons you need to start hcitool in parallel.

hcitool lescan --passive --duplicates

Only if you have both command running at the same time you will receive reading from your Tilt Hydrometer.

The tilt_hydrometer command supports different operations, that also can be used in combination:

As mentioned before, posting data to Brewfather, works by just using the -b option with as Custom Stream URL. There is an optional -i argument, that can be used to set the reporting interval in seconds, default is 900 (15 minutes).

[sudo] tilt_hydrometer -b http://log.brewfather.net/stream?id=abcdefghijkl123 -i 900

Publishing the your readings to an MQTT broker works by using the -m option with a MQTT URI. Using -p to set a MQTT-topic prefix is recommended.

[sudo] tilt_hydrometer -m mqtt://192.0.2.1:1883 -p foo/bar/

TODO

Having to start tilt_hydrometer from the commandline is not very convienient and does not restart the software upon crashes or system reboot. So it is recommended to setup tilt_hydrometer as a systemd service.

Create a systemd service file in /etc/systemd/system/tilt_hydrometer.service with the following contents:

[Unit]
Description=Tilt Hydrometer
After=network.target

[Service]
ExecStart=/usr/local/bin/tilt_hydrometer -b http://log.brewfather.net/stream?id=abcdefghijkl123 -i 900 -m mqtt://192.0.2.1:1883 -p foo/bar/
WorkingDirectory=/home/pi
StandardOutput=inherit
StandardError=inherit
Restart=always
User=root

[Install]
WantedBy=multi-user.target

Adjust the paramaters in the ExecStart command to your needs.

Then start the service:

sudo systemctl start tilt_hydrometer

And enable it to be reastarted upon failure or reboot:

sudo systemctl enable tilt_hydrometer

tilt_hydrometer relies hcitool to be running and scanning for BLE beacons. So you need to start this also as service.

Create a systemd service file in /etc/systemd/system/tilt_hydrometer_ble_scanner.service with the following contents:

[Unit]
Description=BLE Beacon scanner
After=network.target

[Service]
ExecStartPre=/bin/sleep 60
ExecStart=/usr/bin/hcitool lescan --passive --duplicates
StandardOutput=inherit
StandardError=inherit
Restart=always
RestartSec=10
User=root

[Install]
WantedBy=multi-user.target

Then start the service:

sudo systemctl start tilt_hydrometer_ble_scanner

And enable it to be reastarted upon failure or reboot:

sudo systemctl enable tilt_hydrometer_ble_scanner

• Read the bluetooth beacons of your Tilt
• Post the data to Brewfather
• Publish the data to an MQTT broker

• Have a nice Web-GUI to manage your hydrometers (use the great GUI provided by Brewfather)
• Calibrate data (can be done in Brewfather)
• Ready-to-use Raspberry Pi image

The TiltPi Raspberry Pi images are a great for getting started quick with your Tilt Hydrometer, but they require a dedicated Raspberry Pi just to read and post the values to a cloud service.

You can setup TiltPi on any Linux computer, without relying on the image, but it is a quite clunky process. It requires a lot of steps, including monkey-patching 3rd party libraries.

If you are using Brewfather like I do, all you need is forwarding the bluetooth readings to the Brewfather Webhook.

Being able to publish the data to a MQTT broken helps to integrate the Tilt with further automation like heating or cooling.