dehli / temperature-bot

Temperature Bot

About

I use this project on my boat to ensure that during the winter months, my boat doesn't get too cold. I have a heater near my engine that automatically turns on any time it gets below 45F.

This project gives me extra safety so that if anything happens to the heater, or electricity, I can appropriately respond before too much damage occurs.

Architecture

On the boat, there's a Raspberry PI that has a temperature sensor and a cell-phone chip. Every 15 minutes it makes an api call to AWS (via Lambda) which results in the current temperature being stored in Amazon DynamoDB (along with the timestamp for when it was collected). Every 1 hour, CloudWatch triggers a step function that does the following.

1. Query for the most recent temperature
2. Check if temperature is more than 30 minutes ago.

• If so, jump to step 5

3. Check if temperature is less than 35F.

• If so, jump to step 5

4. Exit successfully
5. Send alert that something is wrong with boat.

Commands

npm run deploy

Setup on PI

1. Ensure all environment variables are set
2. Run pip3 install boto3
3. Copy ./pi/main.py onto device
4. Setup Cron (add the following line to /etc/crontab

*/5 *   * * *   user-name      . $HOME/.profile; python /home/path/to/main.py

Note: 5 can be swapped out for another value depending on how often you want to collect the temperature.