Software apps and online services
Forgetting the laundry in the washing machine is a common household problem. Most laundry rooms are in the cellar, either in the cellars of single-family homes or in apartment buildings with shared laundry rooms. The duration of every washing programs is different and, in case of more sophisticated control programs, it may even depend on the washing load of the machine. This makes keeping track of the washing extremely difficult. The operator is inclined to turn to other things and the washing slips one’s memory. Maybe attending to children or elderly people, having appointments or simply other tasks can easily push the laundry from the mind. As the interior of a washing machine is moist and humid after washing with probably a warm temperature after a program that has applied heating, mold and bacteria start developing within a short period of time. In the worst case, the operator washes the clothes again to remove the stains and smells that have built up in the clothes. This poses a serious threat to both the clothes and the environment. High-efficiency washers use about 60-120l of fresh water and about 1kWh per load (500W, 2h). Older models can easily double the usage. Also, washing clothes again adds to the wear of the fabric. If only 1% of 37.5m households in Germany would rewash one load every week, it amounts to a total of ~2m extra washings per year, i.e. 120.000-240.000m³ fresh water and 2.000MWh. By reminding the operator of forgotten laundry, LaundReminder helps the environment, the economy and of course the clothes owner.
The device consists mainly of an IoT device to monitor the washing program and operations is realized on a breadboard with the provided Particle Photon as embedded system controller.
The Particle Photon includes an acceleration sensor, which combines three sensors (accelerometer, magnetometer and gyroscope) into one single sensor in order to detect the different washing machine states through the virbation of the machine. The goal is especially to detect the spinning state, which happens at the end of a washing program and afterwards send a mail notification to the user.
If the end of a washing cycle was recognised, the device starts a timer and will send a notification to the user every hour until the device senses some sort of impact that would occur e.g. when laundry is removed.
The several status changes/updates are transmitted via a Message Queue Telemetry Transport (MQTT) client to Losant (Cloud). Losant itself offers the funcitonalities to design workflows triggered by various event sources. A Losant workflow (Losant LaundReminder Application) has been developed to trace device status updates. In case a device status update includes the timer threshold time, an HTTP POST request is sent to trigger a custom If-This-Then-That (IFTTT) event. The IFTTT event then triggers the mail notification to the user containing the time that the laundry has remained in the washing machine and a gentle reminder to get the load out.
Furthermore, to ease handling of the device in a laundry room, a LiPoly/LiIon charger is used with a 2000mAh battery as an independent power supply.
To put the device in operation, a user can simply place it on top of the washing machine or attach it to the side of it regardless orientation. However, the device should be attached firmly to the washing machine to let it sense the vibrations of the home appliance. If soft materials dampen the movements of the washing machine, the device will not be able to detect the operation mode.
Once the device is in place, it can be powered on. At its first activation, the device will sense and learn its environment. The learning phase allows the device to sense vibrations in a calm, non-operating situation. It will trace acceleration for 60 seconds and neither the machine nor the device should be moved or pushed during the learning phase. The learning is indicated by a red blinking LED while the green LED is alight to show it is operating. Once trained, the device will stop blinking red and keep its memory until power loss or reset.
To setup the device:
1. Power on the device
2. Firmly attach it to the washing machine
3. Make sure the washing machine is not washing
4. Press the button and step back
5. Wait for the red LED to stop blinking
Once the device has been setup, it can be switched on and off using the button. A user may as well leave the device always on. To trace a washing, the device should be on (green LED on). An operator can use the washing machine as usual. While on, the device is constantly monitoring acceleration. It detects a vibration frequency of 100Hz in 1 minute intervals, which is difficult but not impossible to fake. Note that the system tolerates slight movements by the operator as long as it is not awaiting the operator to remove the laundry.
Once the device senses a washing is going on, it turns off the green LED and switches the yellow LED on. When the washing machine rests, the device will switch to the red LED to show that it has sensed that the washing machine has stopped operating. If the machine starts washing again, it will simply switch back to the yellow LED. When the washing machine finally returns to rest, the red LED indicates that the device thinks the washing has finished and that a timer is active. Once every hour, it will notify the user to remove the laundry.
Overall, the development of the LaundReminder IoT device and Cloud application is an example of engineering that contains aspects required to develop embedded systems for the Internet of Things.
The project was an outcome of a workshop about "Embedded Systems Engineering - IoT Applications Prototyping" at the Brunel University London guided and instructed by Dionysios Satikidis.
All team members of the project:
- Manuel Stein
- Maik Betka
- Alex Friesenhahn
- Kevin Poggemann
are M.Sc. students of the School of Engineering and Design at the Brunel University London.