Washer/Dryer notification
Atticus wrote 02/08/2022 at 01:04 • 0 pointsgetting tired of my roommates leaving their shit in the washer/dryer so I am thinking of a project to send a notification in the groupchat. main problem is how to know when it is done.
current ideas: a plug that knows the electricity draw and when it is below a certain threshold it sends a notification, hacking the machine and intercepting the end signal wires, a microphone that checks for the specific frequency of the end signals
problems: products similar to plugwise are expensive, im renting so all splices must be reversible, audio filters aren't difficult but may have a highest chance of not working.
I also saw a project here of someone using an accelerometer? not really sure how they did that as there was little explanation
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Buy a ESP826x based Wifi power switch with current sensor (~15€), flash it with Tasmota, done.
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I did this couple years ago. accelerometer is not good for detecting washer since the vibration is pretty low.
My washer / dryer will play a sound when it's done. I use a microphone to listen to any music / pattern, if similar pattern is heard by microphone. Alert will be triggered. I used ESP32 for this, I used FFT for music / frequency matching. Nowadays, maybe tinyML is more suitable for this by using Raspberry Pi with voice recognition.
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The easiest way to detect that a clothes dryer is done would probably be to detect ~vibrations~ or a lack thereof, since most consumer dryers spin an internal drum to shake out water (tumble dry). Some of them also output a beep/bzzt noise when they are done. An accelerometer might be an option if it's sensitive enough, but unless the dryer is bolted down somehow you may need to recalibrate somehow for slight shifts in the rest position.-- It would probably be smart to integrate at least two ways of checking
FWIW, you probably also want to detect when it's started just to make it less sensitive to human error (failing to indicate drying start time). If it's okay to modify the washer, wiring directly to the start button (or whatever it uses) is an option. Otherwise you might want to make the circuit detect start/stop and possibly whether the cycle was interrupted.
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I'd start by grabbing a 3axis accelerometer attach to the machine with double sided tape or similar. Grab an Arduino/Raspberry Pi, write a simple program to read the device / I2C, and print to serial. In the Arduino IDE, or RPI, run the program, run a load of wash, and then save the output as a .csv.
Now with the .csv, you can open in Excel, and plot the output vs time, so you can 'see' what the movement looks like. You should be able to easily see the various segments of the run. Start the timer at say, the first spin cycle, end it after the last spin cycle && a certain amount of time has elapsed.
RPI with Python/Flask could work great for this.
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May I suggest looking up Matthias Wandel on YouTube? He's done some household current monitoring setups that you might find useful:
Monitoring Power Use with Temperature Sensors: https://www.youtube.com/watch?v=wfOWOre-RYE
Inductive Current Measuring with Raspberry Pi: https://www.youtube.com/watch?v=P47pjVyPP3w
The former works well for long-running tasks like washer and dryer use, while the latter only works with ROMEX-like, parallel, non-twisted wire. It's surprising what you can get out of straight wire like this!
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Here's a more basic one instead of the relay switch.
https://www.crmagnetics.com/remote/cr2550?gclid=Cj0KCQiAmKiQBhClARIsAKtSj-lvnQCMVpqN2uOGr7gPO7-n2GI4dPdjbLrAHyuehSI5tvRnBkTzdrkaAkblEALw_wcB
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search for
AC Current Sensing Switch
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I have a sensor that goes on one leg of the dryer cable to turn a boost fan on. Very simple device.
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Wondering if a Hal effect transistor is sensitive enough or if it would even work when placed along the power cord. Does an AC line under load produce enough magnetic field to be readable by that?
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Pretty sure you would need to separate the hot and neutral conductors to do this. The return current will cancel the outgoing current magnetic fields. It is the same situation with a non-contact ammeter.
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Some modern washing machines have a simple web dashboard built in. Ours is a vZug; wifi needed to be activated. Check your manual, you might be in luck.
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I bought a module with LM567 and tuned it to detect a specific tone (2400Hz, measured using smartphone) emitted by my washing machine when it begs for attention at the end of the cycle. Washing machine beeps loudly 3 times so the solution is quite robust to general noise.
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If there is a light or display signaling it is finished you can try some photo sensor.
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Our washing machine vibrates slightly during the washing process. Maybe you can use a vibration sensor to detect when the program is finished.
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Does the washing machine have a buzzer or beep when it is done? The one we have beeps loudly at a frequency that is well above the normal noises the machine makes. That seems like a good no-contact method
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