Problem

Our washer and dryer are on the second floor of our home and we cannot hear the end of cycle notification sounds when we are downstairs or outside. This resulted in countless loads of wrinkled laundry and wasted time where the machines were sitting idle between loads.

Solution

I created an electronic device that monitors the washer and dryer and sends a text message as soon as a cycle completes. The device's interface has a toggle so we can select who should receive the notification, my wife or I. This solution did not require opening the washer or dryer which would have voided the warranty. The total cost for this solution was approximately $100 USD.

How it Works

The device interfaces with the washer and dryer via short extension cords with non-invasive current sensors. The cord is plugged into the wall outlet and the washer or dryer are plugged into the extension cord.

The device monitors the current flow through the extension cord. When the device detects a current draw greater than a configured threshold value it will set a flag. Once the current draw drops below the threshold value for longer than a configured duration interval a text message will be sent. To send the text message, the device makes a web service call to my THNofiy service via WIFI. That service logs the notification details in a database and sends the text message using the Twilio service. The web service allows for changing phone numbers and message content without having to reprogram the laundry monitor device.

Front of the device:

Inside the device (the board in the center is an Arduino Pro Mini 328 - 3.3V/8MHz and the board on the right is a RN-XV WiFly Module):

The device was programmed with Processing and C/C++ using the Arduino integrated development environment.

Console diagnostic mode while connected to a computer:

Initial prototype: