Neuroheat

This is another version of the Heating Brain hobby project - an Elixir application for controlling the floor heating system in the house. It utilizes a Raspberry PI Zero, a relay controller, and a few 1-wire temperature sensors. The original Elixir application ran for over three years without any issues (except for CPU and memory utilization when rendering data). It provided around 20-30% savings in gas consumption compared to the previous "industry standard" devices (mainly due to optimized logic for enabling and disabling heating in the context of the required heat area).

Disclaimer: This is a hobby project, and I do not take any responsibility for any issues or damages that may arise from running this software. Use it at your own risk.

Development

Install tools required by the .tool-versions file and ensure you have the following system packages installed on your macOS:

brew install arm-unknown-linux-musleabihf
rustup target add arm-unknown-linux-musleabihf

Heating-related logic

See src/controller.rs and src/scheduler.rs for the main logic of the heating system. The controller is responsible for turning the heating on and off based on the temperature readings from the sensors and the expected temperature (according to the heating_config.json file). The scheduler is a cron-like worker that reads temperatures and calls the controller for valves and the stove. You may want to adjust constants in those files (e.g., the minimal floor heating area that is open before turning on the stove).

Deployment

There is a bin/deploy script that builds the binary file and performs actions on the remote server (e.g., backing up the database, updating the systemd service, etc.). Make sure to review the heating configuration (e.g., GPIO pins, sensor identifiers, etc.).

If deploying for the first time, you will have to set up the server (see Raspberry Pi Zero Setup section) and create heating_config.json (see heating_config.json.sample).

Accessing API endpoings

You can access all data by hitting the API endpoints with cURL. The host name depends on your server configuration. Also, keep in mind that the scheduler needs to populate some data before you will see any results (prior to that, it will return HTTP 404).

neuroheat λ curl neuroheat.local:3030/api/temperatures/office | jq
{
  "timestamp": "2024-10-06 10:32:03",
  "temperature": "21.937",
  "key": "office",
  "label": "Office",
  "expected_temperature": "21"
}

neuroheat λ curl neuroheat.local:3030/api/state | jq
{
  "living_room": {
    "label": "Living Room",
    "timestamp": "2024-10-06 11:16:03",
    "heating_enabled": "false",
    "temperature": "22.5",
    "expected_temperature": "21"
  },
  "pipe": {
    "label": "Heating Pipe",
    "timestamp": "2024-10-06 11:16:01",
    "temperature": "30.375"
  },
  "bathroom": {
    "label": "Bathroom",
    "timestamp": "2024-10-06 11:16:02",
    "temperature": "21.625",
    "expected_temperature": "21",
    "heating_enabled": "false"
  },
  "office": {
    "temperature": "22.312",
    "timestamp": "2024-10-06 11:16:03",
    "label": "Office",
    "expected_temperature": "21",
    "heating_enabled": "false"
  },
  "bedroom": {
    "label": "Bedroom",
    "expected_temperature": "18.5",
    "timestamp": "2024-10-06 11:16:04",
    "temperature": "20",
    "heating_enabled": "false"
  },
  "guest_room": {
    "label": "Guest Room",
    "timestamp": "2024-10-06 11:16:05",
    "temperature": "19.625",
    "expected_temperature": "18.5",
    "heating_enabled": "false"
  },
  "stove": {
    "label": "Stove",
    "heating_enabled": "false",
    "timestamp": "2024-10-06 11:16:05"
  }
}

Accessing the database console

Install sudo apt install -y sqlite and run:

sqlite3 /srv/neuroheat/neuroheat.db

Accessing logs

journalctl --unit neuroheat.service --lines=50 --follow

Incompatible changes in the database schema

This is a hobby project, so it does not implement any migration mechanism (yet?). If there are changes in the schema (i.e., src/repo.rs's init function), you may need to re-initialize the database:

1. Stop the service on the server:

   sudo systemctl stop neuroheat.service

2. Remove the database on the server:

   sudo rm /srv/neuroheat/neuroheat.db

3. Let the application initialize it from scratch on startup:

   ./bin/deploy

Raspberry Pi Zero Setup

On the memory card

1. Install Raspbian Buster Lite on the memory card. See official documentation for details.

2. Copy server/config.txt onto the card (as config.txt).

3. Configure the network connection by creating a wpa_supplicant.conf file on the card with the following content (adjust the credentials):

   country=PL
   ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
   update_config=1
   network={
       ssid="[wifi-name]"
       psk="[wifi-password]"
       key_mgmt=WPA-PSK
   }
   

4. Enable SSH by creating an ssh file.

From the host system after booting the server:

1. Allow password-less SSH connections:

   ssh-copy-id pi@[ip]

On the server

1. Set the hostname:

   sudo sed -i 's/raspberrypi/[neuroheat or any other hostname]/g' /etc/hostname
   sudo sed -i 's/raspberrypi/[neuroheat or any other hostname]/g' /etc/hosts

2. Fix the cannot change locale (en_US.UTF-8) issue:

   sudo sed -i 's/# en_US.UTF-8 UTF-8/en_US.UTF-8 UTF-8/g' /etc/locale.gen
   sudo locale-gen en_US.UTF-8
   sudo update-locale en_US.UTF-8

3. Set the new password:

   sudo passwd pi

4. Upgrade the distro:

   sudo apt-get update
   sudo apt-get dist-upgrade
   sudo apt-get autoclean

5. Set the local timezone:

   sudo timedatectl set-timezone Europe/Warsaw

6. Configure rsyslog (optional):

   # /etc/rsyslog.d/01-ignore-rngd.conf
   if $programname == 'rngd' then /var/log/rngd.log
   & stop
   
   if $programname == 'rng-tools' then /var/log/rngd.log
   & stop
   
   # /etc/rsyslog.d/02-cron.conf
   if $programname == 'cron' then /var/log/cron.log
   & stop
   
   # /etc/rsyslog.d/99-nas.conf
   use local address like "rsyslog.local"
   *.* @[ip address of log server]:514
   
   $ActionQueueFileName queue
   $ActionQueueMaxDiskSpace 1g
   $ActionQueueSaveOnShutdown on
   $ActionQueueType LinkedList
   $ActionResumeRetryCount -1
   
   # /etc/logrotate.d/rsyslog
   /var/log/rngd.log
   {
     rotate 4
     weekly
     missingok
     notifempty
     compress
     delaycompress
     sharedscripts
     postrotate
       /usr/lib/rsyslog/rsyslog-rotate
     endscript
   

7. Create application directories:

   mkdir -p /srv/backups /srv/neuroheat /opt/neuroheat/bin
   chown -R pi:pi /opt/neuroheat/ /srv/backups/

8. Configure backups:

   # Add in crontab:
   
   0 * * * * cp /srv/neuroheat/neuroheat.db /srv/backups/neuroheat.db.$(date +'%Y.%m.%d.%H.%M').bak
   15 10 * * * find /srv/backups -type f -mtime +14 -ls -exec rm -f -- {} \;
   

9. Install jq for server/bin helper scripts:

   sudo apt-get install jq

From the host system after setting up the server:

1. Deploy the code:

   ./bin/deploy