Modded Microwave Sets Its Own Clock

Of all the appliances in your house, perhaps the most annoying is a microwave with a flashing unset clock. Even though a lot of devices auto-set their time these days, most appliances need to have their time set after being unplugged or after a power outage. [Tiago] switches off power to some of his appliances while he’s at work to save a bit of power, and every time he plugs his microwave back in he has to manually reset the clock.

Thankfully [Tiago] wrote in with his solution to this problem: an add-on to his microwave that automatically sets the time over the network. [Tiago]’s project uses an ESP8266 running the Lua-based firmware we’ve featured before. The ESP module connects to [Tiago]’s WiFi network and pulls the current time off of his Linux server.

Next, [Tiago] ripped apart his microwave and tacked some wires on the “set time” button and on the two output pins of the microwave’s rotary encoder. He ran all three signals through optoisolators for safety, and then routed them to a few GPIO pins on his ESP module. When the microwave and the ESP module are powered up, [Tiago]’s Lua script pulls the time from his server, simulates a press of the “set time” button, and simulates the rotary encoder output to set the microwave’s time.

While [Tiago] didn’t post any detailed information on his build, it looks like a great idea that could easily be improved on (like adding NTP support). Check out the video after the break to see the setup in action.

49 thoughts on “Modded Microwave Sets Its Own Clock

    1. Hello.
      I measure the power consumption of the ESP8266 and it is about 1Wh maximum (while transmitting). Since the power consumption of the microwave on stand-by is about 6Wh , and that the microwave is off most of the time,
      I think the extra power required by this add-on is negligible …

      1. So, when in standby, the microwave uses 53KWh per year. Given that electricity costs about 15c/KWh (give or take), congratulations, you saved less than $8/year by switching your microwave off.

        1. I think of this standby energy wasted in terms of how much I should be on a bike to generate it: considering that I can do about 150W for a long time, that would mean 460hours, or 3 months if you did that in a normal 8h/day job. This is just to point out the scale of the waste.

          The thing is, that if they used a very efficient power supply and turn off the display if you did not set the clock, the 8W could easily be 0.2, and this could be done within the $8 you pay for electricity for the first year. But consumers don’t care about that because they are dumb.

          If you ask me, a law that would minimize total cost over the life of the product would solve this issue: they would be forced to make a $60 microwave that burns 0.2/year in standby instead of a $50 that burns $8/year in standby.

        2. Zac, the microwave shares power with an induction cooker, an electric stove and other appliances. All sum up waste 25Wh on standby. Add that to other appliances (TV,home cinema,sat box,etc) and the standby waste reach 50W. I turn all this off and save about $50/year.
          Not much, but significantly to me…

          1. How much power did your soldering iron consume to make the modification? How much power did your PC consume as you drew up the schematic and did the board layout? How much power did it take to manufacture the board? How much did it cost you to make this modification?

    2. i think this hack is more about never manually setting the clock again, in cases where power is disrupted either intentionally or by means of outage. however, as you eluded, it provides a means to manually powering off/unplugging without the frustration and time spent setting the clock.

    1. I’m currently doing something similar; using a pair of xbees to ‘beacon’ out time (and alarm clock status) from a good ntp/gps rasp pi box to anything else in the house that needs time to be set (or show an alarm count-down). the wifi module would work, too, but I kind of like the xbee stuff a little more for some odd reason.

      when you have ‘network time’ you don’t really need local clocks anymore (as in ds1307). I built a nixie clock that is ‘clockless’ and relys on the xbee beacons to get time from. sure, it uses its local software millis() clock and Time.h routines but it still has no true RTC and gets timing updates every minute from the xbee mesh network. and for fun, my arduino clocks blink twelve (lol) after power up and until they receive and parse their first time beacon packet ;)

      any clock that needs manual setting is out of place in this day and age!

      1. aren’t xbees in the 40 euro price range? Adding a raspberry pi sums up a lot more money. I imagined reprogramming the 3dollar ESP to answer over IIC like the ds1307 would be a cool and cheap way to replace the local clock.

        1. xbee’s are $18 on mouser, at least for US folks. they are not dirt cheap but they are cool as can be and they avoid the whole wifi thing, which I kind of like (no security issues to care about, no coding passwords into code). you can configure xbees to be encrypted, too, I think (but I don’t bother since I don’t do anything critical with them, so far).

          the benefit of the broadcast/listener scheme is that I can change ALL clocks in my house (that are xbee-ready) with a change of the main central server. the rasp pi is there anyway, its my stratum-1 timeserver:

          xbee sender (usb xbee):

          and one example of an xbee-ready clock is my new DIY nixie build:

          so far, its working pretty well. and yes, it costs money for hardware ;) but the ‘one talker, many listeners’ idea is one I like to use for this application. the timeserver sends out the data over xbee (it only transmits) and all the other ‘clients’ in the house are listeners (only). this simple scheme lets me sync all clients at once or even put the clocks into countdown alarm mode; and once the alarm entry has been set on the rasp pi server, anywhere I’m at, in the house, I can see when my pizza or laundry is about to be done ;)

          (also, I plan to be able to send ‘messages’ to the clocks^Hdisplay devices, so that if some other value makes sense to be displayed, it can be – via a broadcast. I have a DIY audio preamp and when I change the volume level, it can send a message to the webserver who relays it to all my ‘clocks’ in the house; just for fun).

          when you go ‘message passing’, you get a WHOLE LOT MORE than just keeping time.

          1. Sounds still doable with the ESP8266, even the messaging stuff, just saying. And it’s hardware and costs money, too. Just not so much ;) You’re trying to “sell” your solution for a problem I don’t have. I want to replace my DS1307 with a cheap wifi module – not with 2 xbees and a raspberry PI and add more clocks. I’d use a 433MHz transmitter and many receivers for your setup – If I would not use it for any “critical” stuff and don’t care for the security stuff. Or “upgrade” to the NRF24L01+ modules. But everybody tackles problems his own way.

  1. The solution to the clock on the microwave is to stop manufacturing clocks on microwaves. That was an idea that was relevant when it first was introduced, as most people didn’t have clocks in the kitchen. These days, there are clocks on everything you look at. Almost every appliance in your kitchen has a clock built in. We simply don’t need all these clocks. A timer is perfectly fine to leave, but really we are getting plenty for the money spent on the appliance, and could do without time. When the power goes out, most of the world has to do the same ritual of setting all the clocks.

    What would be smart is one clock for all devices. Perhaps a smart connected stove, refrigerator, microwave and coffee maker that accesses the time and location through your smartphone so you could set the temperature, cook time and when to start for the stove. Set the time to start brewing for the coffee. Set a reminder to get milk and eggs when the fridge detects you are at the store after you get off work. Why aren’t appliances doing this yet?

    1. In a perfect world, where there was no such thing as trolling, this would be great.
      The smart phone is really the weak link here, since I doubt manufacturers are go to bother secure all of those appliances against remote tampering.
      It wouldn’t have to be anything particularly bad, just have the fridge falsely report food levels a few times, and most people will abandon the system.
      The power of inconvenience is great .

      1. If you are even hinting at the notion I could be trolling, then you are completely in another galaxy with your hypothesis. Manufacturers get together all the time to agree to a protocol. Perhaps you’ve heard of HDMI, VGA, Blu-ray, dvd, USB, um… the freaking metric and imperial system… I could go on. Likely forever. The problem is getting manufacturers to agree on a common protocol, and that comes out of necessity for the consumer. Some idiots have proprietary protocols (apple) and they get by fine, some died for it (zipdrive). The common clock thing shouldn’t be a problem to solve. After all, we have atomic time. So if they don’t want to play together, and you don’t want to own all Samsung appliances and control with your Galaxy phone, at least they could stop putting clocks on your knives and spoons.

    2. Your first paragraph seems to indicate you are missing the real point of the clock on the microwave. The clock is there so that you can load the microwave up with something frozen and set the microwave to cook it at a certain time. For example… you could have dinner waiting for you when you get home. I’m not sure if anyone ever uses that feature. But.. it’s there on pretty much every digital microwave I have seen and it obviously requires a clock.

      I’m pretty sure that if people needed a clock for their kitchen they have been very much available to put on the wall for a very long time now!

      In your second paragraph you suddenly seem to know this. I don’t think your central clock idea would work very well though. Most likely every manufacturer would design their own proprietary, incompatible system. It would be vendor lock-in something fierce. Then to be really evil they would probably make a new, incompatible system every so many years. When one apliance dies you would end up having to replace everything!

      I do like the concept though. I just finally replaced my old analog-timer microwave about a month ago. Part of the reason I kept it was because I figured that analog timer would be simple to replace. I wanted to build my own. I was going to put a HopeRF module in it.(had this idea before ESP8266) Then I was going to give it buttons for each family member. Push your button, set the timer and it sends a message to your phone when your food is ready. I probably never would have gotten around to it and we needed a bigger microwave (ok I needed a bigger microwave) at the hackerspace so I took it there and got a new one for home.

      1. I have never met this mythical person who sets the alarm on their microwave to power up at a certain time.

        McNugget is right; clocks in ovens (all types) are pointless. Good source of VFDs though.

        All you need is a knob you twist to set the cooking time (few even bother setting the power, but ok if you insist). Check out commercial microwave ovens some time, they don’t even have turntables.

        1. Well, now you have. I haven’t done it often, but being the tinkering sort I had to try it. Works best for non-frozen/perishable foods so things like baked potatoes can be ready to go before you start anything else. That said, clocks really aren’t necessary per the rest of the discussion but are a “everyone has one” byproduct of the timers that *are* necessary:

          “We just built a controller that will stage through a wait/defrost/pause/cook cycle, has six automatic food settings, and also measures the humidity of the exit air to tell when food’s done”.

          “You have the display and the timer – add a clock so we can be like everyone else”.

          “But nobody uses the clocks and they’re a pain to set”

          “If we don’t have one we have to sell the oven for less…put it in”.

          All of this aside, I just don’t set the time on mine.

        1. i think he is mistaken. i know that power companies adjust the frequency ever so slightly throughout the day so there’s an exact amount of cycles/day, but there’s no way to get the time of day extracted from it. maybe he means wwvb?

      1. there is no powerline ‘set the time’ protocol. 60 or 50hz, yes, and you can get relative timing from that, but not absolute timing.

        the longwave stuff (‘atomic clocks’) don’t use powerline at all; they wait until night for a clear rf reception window to read the very slow baud rate that has absolute time in it (btw, it takes about a full minute to convey the time using that old slow longwave protocol).

        1. My digital bedroom clock somehow sets itself as soon as it’s plugged in. It’s not atomic, and was advertised as setting itself from the power line.. I’ll have to dig up the model number. It’s blue LED and had good Amazon reviews. It’s across the room and wife is sleeping….. :)

          1. Some are set via WWV, which is basically a radio signal the clock has electronics to detect, or some simply use a low power real time clock inside. They are set one time at the factory, and then you set the time zone and away it goes.

    3. Truth. I don’t need a clock on the microwave. I’ve never once set a microwave to start cooking something at a specific time. I can’t even think of something lending itself to being cooked that way, that I would consider worth eating. Though I disagree with you on the solution. Don’t stop putting clocks on microwaves, instead make it a feature that stays out of the way for the 99% of people who don’t need it. My current microwave doesn’t blink 12:00, if the clock isn’t set the display simply remains blank. It presumably only bugs you about not knowing the current time if you’ve actually set a cook timer. That’s the way it should be.

      And if a self-setting clock is desired, I wonder why everyone tends to reinvent the wheel. There’s been a solution to that for more than 50 years – WWVB. Seems receiver modules are now nearly unobtainium, but until a few years back, were available for $7. Given WWVB’s low transmit frequency of 60Khz and very low bitrate, plus MCUs with fast ADCs, integrated op-amps, and current DSP techniques, I bet it’s possible to hack together a receiver with a MCU and very few support components. A quick search didn’t turn up much, but I found something that suggests it has been successfully done by connecting a loopstick antenna directly to a MCU’s ADC:

      Should there exist a detailed, replicable description of such a project, that is something I’d very much like to see featured here.

    4. Bells and Whistles, the microwave oven already has a display (to show the remaining cook time and power level), it already has a microprocessor with a timer function, all that needs to be added is a “Clock set” button and a little firmware. It would be a waste to leave it out… Now if that processor could be replaced by the ESP8266 or whatever, it could get NTP from the house router, for probably no extra cost.

      1. Featuritis, like everything else. Bigger list = better item.

        I’m surprised microwave ovens don’t include an FM radio as well, though I won’t be surprised if ones exist that link to a shitty phone app to tell you it’s done (like washing machines do).

        There’s a pointless hack for someone; use your phone to run the microwave (claim it’s kid-safe or something as the oven itself has no controls).

        The best ovens have just two knobs, one for time & the other for power (rather rare in some market due to featuritis). I’ve yet to see one go to 11.

  2. The 8W or so idle consumption and drifting clock is why i just plugged my microwave in a switched plug.

    But i have to admire the build, there is something really neat about setting the time by pressing the buttons virtually.

  3. Or perhaps use a supercap to maintain the time as coin cells are obsolete for RTC use now. A supercap can power up an RTC for several months. Nothing serviceable required.

  4. I would argue that a far larger problem with microwave ovens is the obnoxious beeps (*especially* endless, annoying “finished” reminders) that cannot be reprogrammed by the user. Another is the “variable power” feature that on all but inverter microwaves (and even on them, mostly) is a (literally) stinking lie.

    The world needs a hacker challenge to create a new universal, open-source replacement controller board for microwave ovens to let us get around old-fogey design engineers who think it’s still the 1960s.

    1. I thought of that idea ages ago, it’s too expensive (a bit less these days with laser and what not to cut custom front panels), but mainly too many legal problems – they’re rather big on that whole safety thing.

      Safety is mostly about interlocks, but the controller needs to be immune to glitches (fail safe).

      The beeps are rather annoying, I’ve modded the occasional resistor into a few. I’d gladly trade both clock & beeps for a turntable that returns to it’s starting position, now that’s handy. A pretty easy hack actually.

      There was a post a while back where someone claimed to have been burnt by a microwave – yeah no. Claimed it was running with the door open (no) because the fan was running – commercial ovens do that. (Commercial/pro stuff always does ‘weird’ things.)

      You might be interested in this:

  5. The microwave I have has this neat little feature – you have to explicitly set the clock if you want the clock display to show up. If you don’t bother to set the clock, there is no clock display. Problem solved.

  6. The biggest problem I can see with microwave manufacturers is the cost to update the technology. They either sell an old school dial timer type, or they sell the pushbutton keypad with VFD or LCD display version. All the digital types have a numeric digit clock from the 80’s, have preset cooking times and some contain a turntable. It’s been this way for decades. Then someone comes along and adds a feature like a color screen and the price doubles. Meanwhile it doesn’t sell because Walmart can sell the boring microwaves for $50. All because the cost to build one is based on the fact that the manufactured parts are cheap from being refined or automated, and better deals with materials. The instant someone innovates the microwave, the cost skyrockets. Partly because the parts aren’t as basically free as they are now, and the freedom to charge for being a pioneer.

    Someone needs to make an open source microwave. Have it run on a Pi, so it can fetch Internet time, best cooking times and hell let’s make it display ads relevant to the types of foods you cook.

  7. I solved this problem in a much better way, that does not require modification of the mw:

    Since my mw, after unplugging Power and replugging, Always set its Clock to 01:01, and goes on from this Point, I solved it in a much better way:
    I used a remote switch (Those “Nexa” radio switches) into the same outlet as the mw.
    Then on my server, that is synced via NTP, I have a “Tellstick” which transmits a off signal when the Clock is 01:00, and a on signal when the Clock is 01:01, by a scheduled task.

    Since the mw Always begin the Clock on 01:01, the mw “sync” its Clock each night 01:01. This means that as long as the mw does have a accuracy smaller than about 1 second over 24 hours, the microwave Clock will Always be in perfect sync.

    This idea can of course be altered depending on which time the mw starts its Clock at after a Power-up. Some start at 00:00, some start at 01:00, some start at 12:00 and some start at 01:01. Its easy to set the tdtool scheduled task to just briefly dump the Power to the mw just Before this time.

    1. “like NTP support”

      ….uh…..why wouldnt the server the esp grabs the time from be ntp synced? Do you mean to discipline the microwave clock? If you need your microwave to have nanosecond accuracy, what you really need is another clock not built into a kitchen appliance. Besides it would have to constantly be resetting the clock which means you would have to add even more surgery to check whether or not the microwave is running, or a cook time was set, or any other some such state. It would be far easier just to get a atomic clock synced wall clock to keep in your kitchen.

      1. And that was supposed to be a general reply, not a reply to this specific thread. I sware ill never figure out how HaD arranges it’s mobile site…. absolute garbo…

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