My Magic Chef microwave oven produces five loud annoying beeps at the end of each countdown, and won't stop even after I've opened the door. So I designed a mod that uses a Pro Mini to monitor the display and press the Stop button when the countdown reaches one second. The "early" termination prevents the five beeps. All the details are in a Github repo:
This only works for my model HNN1110W purchased in 2020, but something similar might work for other microwaves with the same feature. Remember that microwave ovens are mains-connected devices with high-voltage capacitors, and can be dangerous to open up and work on.
Because the beep is useful. The keypad is just membrane, and it's hard to tell if you've pressed a key. The beep on keypress tells you that without having to look at the display. Also, I still want something to happen when the countdown finishes. Now I get two fast beeps instead of the 5-second barage.
Yeah. I mean it's supposed to be a hobby, right? Actually, it's kinda neat that it works. I wasn't sure I would be able to figure out how the oven drives the display. It turned out to be a really oddball algorithm that I've never seen before. Anyway, it was fun working on it for a couple days.
