Appliance Monitor Is Kinda Shaky

Lots of people set out to build appliance monitors, whether it be for the fridge, the garage door, or the washing machine. Often, it’s nicer not to cut into an appliance to make direct electrical connections, especially when mains power or water is involved. But how else can we know what the appliance is doing?

[Drew Dormann] wanted to smarten up his old washing machine, so designed a system that uses a vibration sensor to monitor appliances. It’s a simple build, pairing the 801s vibration sensor with a Raspberry Pi Zero. Naturally, adapter boards are readily available to make hooking things up easy. Then it’s just a matter of tying it all together with a simple Python script which sends notifications using Twitter & PushBullet.

It’s important to note that this approach isn’t just limited to washing machines – there’s a whole laundry list of home appliances that vibrate enough to be monitored in this way! It’s likely you could even spy on a communal microwave in this way, though you might struggle with WiFi dropouts due to interference. Build it and let us know.

[Drew]’s build is a great example of what you can put together in a few hours with parts off the shelf. For those that consider the Pi Zero overkill for this application, consider this vibration-based laundry monitor based on the ESP8266. Think you can do better? Show us what you’ve got on!

24 thoughts on “Appliance Monitor Is Kinda Shaky

  1. For the microwave… use a different frequency. A 2.4GHz microwave oven is unlikely to cause much interference on 27MHz. (There’s a Low-Interference Potential Device allocation down there for remote control cars and such, fairly low bandwidth and ERP but this doesn’t have to be high data rate.)

    1. 27 mhz is swamped with ionospheric interference some years of the solar cycle. i had a cb radio that recieved strong international signals without coax connected. it is best not to use hf frequencies for that purpose.

      1. Naw.. that (26-27) HMz would unreliable for the long term. Even during the portion of the high subspot activity, there are lulls in the interference, the reciprocal of that is during periods of low sunspot activity there are periods of interference, both unpredictable. Anyway after local sunset inference generally subsides.

      1. Not in Australia. Here, the legitimate users for 433MHz are:
        Primary Service: Radiolocation
        Secondary Services: Amateur Radio, Land Mobile Radio

        The situation may be similar in other countries.

        Note that LIPD does NOT appear in the above and it is NOT an ISM band. Frankly, we license holders are sick of overseas shite clogging up the top end of 433MHz. This is crap that never should have been permitted to be imported, but we now have to put up with because the ACMA was asleep at the wheel and woke up when it was all too late.

        27MHz almost certainly can do much longer distances and will suffer ionospheric interference as a result, but how often has this affected your remote control car from years ago operating on 27.145MHz? It has to get maybe 10 meters from the kitchen to a gateway… not to the other side of town.

  2. Wonder if a Kill-a-watt has enough resolution to be useful here. A water pump turning on or spin cycle starting has to be noticeable to power spike. Certainly easier to splice a ESP or something into a kill-a-watt than meddle with mains power in your appliance.

    1. It has the resolution but how would you interface to it? Do they have a version with a dry contact or other means of sending a signal out? Hacking the display doesn’t seem particularly straightforward.

      Could also use a CT coil as a different method of measuring “non contact” electrical usage.

        1. The kit price of $167.51 plus you have to assemble everything as well feels kind of steep. Are there any other off the shelf solutions out there that cost less but would act as a simple “pass through” type device but also supported sending the resulting cleanly formatted data to something or at least logging it instead of it clearing upon power off?

    2. The Sense Energy Monitor, which monitors whole-house energy usage at your circuit box, can determine when appliances stop or start from unique usage patterns- and it just got IFTTT integration. From what I understand appliance detection is good-not-great but improving.

  3. You know how you can get Android phones at ridiculously low prices because they are on a pre-paid plan, subsidised and locked to a network? Well they still work find around the house via wifi for these types of projects and their ability to sense and make sense of different vibrations is very good. :-)

  4. A killawatt could work, but not by detecting power spikes, but rather detecting when it stops drawing power.for a certain time.

    A washer stars and stops motors and pumps all the thime and even if you were to count the number of times the evacuation pump normally starts, that could differ depending on the ammount of clothes, or what program you are running.

    My washer even “senses” how many times it has to rinse, sometimes 3 times, sometimes 5.

    The best bet is to watch it go idle for a determined time to be sure it is done, just like the vibration sensor does I guess.

  5. I find it interesingthe sometimes clever machinations some go through to avoid with working with directly with line voltages, when working with them simpler less complicated solution. Even Limor Fried, an electrical engineer has shown in one of her projects an irrational fear or a lack of knowledge to work with main voltages safely Perhaps HAD should produce a series of on how to work on mains voltages safely, and the higher DC voltages present in older electron tube gear. Not any news that some solid state gear containing CRTS can have higher DC voltages laying in wait to bite the uneducated.

    1. But answering your main point — I totally agree. We’ve been cautious about running mains hacks b/c, well, we don’t want people who don’t know what they’re doing to get electricuted. But that’s lame, no? Instead, it’s much better to showcase projects that exhibit good safety, while getting the job done.

      So go to it, Hackaday community! Document your mains-electricals projects. For the good of all mankind.

      1. Meddling with the mains section of devices not only void warranty but makes you liable for any mishap.
        And if it’s simple to detect vibration and that works just as well and in universal and doesn’t require modifying a device and can be moved to anther device without renewed modification then I have my view of which is the best solution.

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