Time to fold alerter

A little rough script to detect a washing machine/dryer load and alert you with Telegram or any other GET webhook when the load is over (multiple urls are supported). Useful when you don't hear the end of cycle sound. It uses the ADXL345 accelerometer with this convenient driver for raspberry pi (tested with raspberry pi 1).

How to use

Make sure you have a functional setup with the ADXL345 and that the sensor is anchored on the machine, ready to measure on the Z axis.

All the steps mentioned here should be executed on the raspberry pi.

Install the driver

1. Clone the repository
2. Copy the adxl345.py file in the same directory as the script OR
3. Add the driver path to your PYTHONPATH environment variable (export PYTHONPATH=$PYTHONPATH:/somedirectory/adxl345-python)

Install the script

1. Clone the repository
2. Run with sudo ./time_to_fold_alerter.py https://api.telegram.org/botxxxx/sendMessage?chat_id=xxxxxx&text=Done https://otherwebhook.com (sudo is required for writing to /var/log)

Optional configuration

On the first run, you can run with the -v flag and this will output relevant information in the log file (/var/log/time_to_fold_alerter.py) such as the maximum acceleration detected in the idle phase detection. You can also configure the idle threshold that is used to detect movement with the -i flag.

Help is also available with python time_to_fold_alerter.py -h :

$ ./time_to_fold_alerter.py -h
usage: time_to_fold_alerter.py [-h] [-v] [-i IDLE_THRESHOLD] [-a ADDRESS]
                               notification_urls [notification_urls ...]

Washing machine/dryer action detector. Logs are in
/var/log/time_to_fold_alerter.log.

positional arguments:
  notification_urls     the url to send the notification to via a GET

optional arguments:
  -h, --help            show this help message and exit
  -v, --verbose         run the program with debug logs
  -i IDLE_THRESHOLD, --idle_threshold IDLE_THRESHOLD
                        the idle threshold for movement detection (default:
                        0.1)
  -a ADDRESS, --address ADDRESS
                        the address of the adxl354 in int or hexadecimal,
                        useful when you use multiple sensors on the same board
                        (default: 0x53)

Install as a service

A SystemD script is supplied in the init-script directory. To use it, modify the ExecStart command to add the notification url and the optional arguments. Set the right permissions (sudo chmod 644 time-to-fold-alerter.service) and copy the file in the /lib/systemd/system/ directory. Enable the service and reboot :

sudo systemctl daemon-reload
sudo systemctl enable time-to-fold-alerter.service

How does it work?

The script uses a very simple state machine since the pi is not really suitable for complex live FFT calculations. It uses the following algorithm :

• poll the sensor for 1 second each 10 seconds
• if output is higher than the configurable idle_threshold, increment a counter and repeat
• if counter > 2, it means we have a load
• loop until the maximum acceleration is below the idle_threshold for 1 minute straight.
• send notification

While the flow is not very elaborated, it's very reliable in my experience but might requires tuning for other machines as I've only tested with one.

Questions or issues?

Open an issue!