Introduction: Microwave Beeper Silencer Hack

In this Instructable I will show you how to modify your microwave and other household appliances so that they don't make annoying beeping sounds! Give yourself the option to operate in "Stealth Mode". I know that I am not the only one to find that the beeps in some appliances are just too loud and may be completely useless and unnecessary. I don't want to wake up the entire house at 6am when I just want to heat up my breakfast and leave for work.

DISCLAIMER: This Instructable is for someone who knows electronics and understands the risks involved in opening up high voltage appliances! It will void your warranty and possibly render your microwave useless. So only attempt this if you know what you're doing and follow safety procedures! Do not activate the microwave with it open.

OK, with that said... Let's get ready to hack!


My Incredibly Annoying Microwave Beeper

I have a microwave that you can see by the video is very loud and annoying. Every time I press a key, I hear a loud beep. When the microwave stops it beeps not once, not twice, not three times... but FOUR FREAKIN' TIMES! And then it also will beep AGAIN when I open the door. Why? Do I really need a bleepin' "beep" to tell me I am opening the door? Argh!

And it's not like I leave the microwave to go to another room and need to hear when it's done to know my food is ready. The microwave makes a loud fan sound as it is... I know when it has finished because the fan turns off and the room is silent. So the beeper is completely unnecessary. Also, when I press the buttons I can see if I'm in the mode I need or if I am keying in the correct digits because the display changes! I don't need an audible beep to confirm that my button press worked.


The Plan

So I concocted this plan long ago to rip out that annoying beeper and put an end to this bleeping madness. But just in case I actually needed the beeper to work for some reason, I figured I'd install a switch to allow either NORMAL function, or what I like to call STEALTH MODE! Ok... So let's get to work!

Step 1: Gather the Tools

Picture of Gather the Tools

You will need a few basic tools to get the job done. I've taken a picture of most, but the last few items in the list are not pictured:

  1. Screwdriver
  2. Locking adjustable pliers
  3. Wire cutters
  4. Multimeter
  5. Soldering iron and solder
  6. Hot glue gun
  7. A length of wire
  8. Switch
  9. Drill

You'll need a screwdriver and perhaps pliers to get your microwave open. Sometimes "security" screws are used so if you don't have the correct screwdriver to open it, a set of locking adjustable pliers will let you clamp on to the head and still turn it open.

The wire cutters are to cut your wire to length and multimeter is to check continuity of your circuit as you are setting it up. The soldering iron is to solder the wire to the beeper and to the switch, so you will need a wire and switch. Finally, the drill is to make a hole in the microwave to pull your wires to the outside where you will attach your switch with the hot glue.

Step 2: Find the Buzzer and Remove Circuit Board

Picture of Find the Buzzer and Remove Circuit Board

Once you have opened the microwave, look for the main circuit board. This is usually located behind the touch-panel where you type in the numbers and settings for the microwave. The main circuit board has the display, and will also have the microprocessor and buzzer/beeper on it.

You will need to keep track of all the wires as you will need to remove this board to make it easier to "operate" on it. As you can see by the pictures, the board is removed and the buzzer is easily identified. It is a round disk with 2 electric metallic leads connecting it to the main board. Your buzzer may be covered by a plastic element and have a small hole in it.

Step 3: Hack in Your Switch

Picture of Hack in Your Switch

Cut one of the leads to the buzzer with a wire cutter, and attach your own wires to each side of the junction you just cut. You should have 2 wires ready (in my photos they are red and blue) to solder to each side of the junction.

You will see in the second photo I have soldered my red wire to the part of the junction connected to the main board, and the other blue wire to the buzzer itself. Now place your board back in the microwave.

In the third photo, I have drilled a small hole on the side of the microwave (through the plastic) and fished the other ends of the red and blue wires through that hole so that they pass to the outside of the microwave.

What I will be doing is simply placing a switch IN SERIES with the buzzer on the outside of the microwave. When the switch bridges these 2 wires, the circuit is complete and the buzzer functions as usual. When the red and blue wires are disconnected by the switch, the buzzer will not get any electricity and won't make any sound!

So I have a switch and connect the ends of the red and blue wires to it on the outside of the microwave. When the switch is ON it completes the red/blue wire circuit and buzzer works. When the switch is OFF, the microwave is in "Stealth Mode" and the buzzer doesn't work!

Step 4: Mounting the Switch

Picture of Mounting the Switch

By this point, the switch is now connected in series with the buzzer and is located on the outside of the microwave, with the control board on the inside. Test out that it works and that you have done everything properly by plugging in the microwave.... but....

WARNING!

Don't actually use the microwave to heat anything! Microwaves could leak out with the device being disassembled. Just plug the microwave in, press the buttons a few times and see if you hear noises when you are pressing buttons. Flick the switch and see what happens. It should let you hear sounds when the switch is in one position, and hear no sounds when the switch is in the other position.

If all is working as it should, put your microwave back together. Now you need to figure out how to mount your switch. I had the option of actually sinking it flat to the surface but I didn't want to cut any more of the plastic out from the microwave case so I decided to just mount it sideways with some hot glue (as can be seen on the photos).

If you want it to look nicer, or if you want to hide the switch, you can use longer wires and have it coming out the back, or somewhere you don't see. I didn't really care, I just wanted it to function and be easy to get to.

Step 5: And You're Done!

Picture of And You're Done!

That's it! Congratulate yourself on a job well done! You can now enjoy your microwave in silence without hearing that annoying beeping sound. The best part is that you still have the option to run it with normal sounds, but if you must be quiet for the sake of the family, the "Stealth Mode" switch you installed will come in handy!

Note:

I would greatly appreciate it if you also watched and rated the YouTube Video and left comments on there as well. Thanks!

Comments

Omnivent (author)2016-02-23

With a loud beeper, there's usually an inductance (coil) involved and when you just open circuit it, the voltage is bound to rise - in some instances to very high levels (like several hundred volt).

I don't know your µ-wave, or how its beeper circuit is constructed, but just as you'd never crank an engine with a spark plug cable removed (as it can destroy the coil), I'd check the circuitry before this mod and place the switch before the driving transistor.

Perhaps there's no issues, but just to be cautious.

Have a nice day :)

edy (author)Omnivent2016-02-23

Good point. I am going to research more into the circuit/schematic and determine what is going on, just to be on the safe side. I've seen other instructables/tutorials where people have just cut the beeper out of the board and did not care. I am fairly certain that as long as you use a big enough switch to handle the voltage spike and not play with it when the beeper may go off that it is unlikely to produce a spark (like a spark gap across the switch due to the inductor). If that is a concern, I would eliminate the switch altogether (or use a larger one). Thanks again for the interesting observation and I will try to find the schematic to post.

Omnivent (author)edy2016-02-24

It's not the switch I'm worried about, but the components in the driver (and perhaps even further "back" (see pic). The driving transistor will likely bite the bullet first though, then short out and protect the rest.

Cutting the base drive instead will have no repercussions.

edy (author)Omnivent2016-02-26

What do you think about me placing a resistor in series with the buzzer. The switch would then either directly link the piezo across the circuit directly (no resistor in series with it), or the switch would bring a resistor in series with the piezo. The piezo may not be completely silenced by the resistor but that may reduce the volume significantly and may reduce the height of the voltage spike by allowing some voltage to "leak through" as normal. Thoughts?

Omnivent (author)edy2016-02-26

A resistor + switch in parallel with the cap will give you more control range (and the load will never be less than the piezo alone). If you know (or can measure) the frequency, you can make the resistor value the equivalent of the piezos reactance for a starting point.

ThomasK19 (author)2016-02-21

I usually calm those pests by applying glue to the beeper, which will be a final silencing. Eventually you could modify this by adding a resistor parallel to the switch which will alternate between loud and low.

You should add a disclaimer since opening a device like a microwave can be hazardous.

edy (author)ThomasK192016-02-22

Good point. I'll add a disclaimer. Also, you could mod in an LED so it would flash. Plus with an IoT board you could even have it send a notification.

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