5 ESP32 projects that make dumb appliances smart without opening them up

Building a smart home is great until you come across a dumb appliance. My first instinct is to grab a screwdriver, open it up, understand the internals, and plug an ESP32 into it. But that also means voiding the warranty and soldering it. It’s natural to dread the soldering part because no one wants to risk it on an expensive appliance.

Over time, I’ve found a better way to use an ESP32 with a dumb or non-smart appliance with Home Assistant. After all, plenty of ESP32 projects give old gadgets a second life. You can take a slightly different approach for each ESP32 board to make the appliance smart without opening anything.

A door and lid monitor

A simple sensor can tell you when the door is left open

I realized I am not the only one who sometimes leaves the wardrobe, a cabinet, or even the chest freezer open. Double-checking is good, but it’s also helpful to have a prompt that tells you if you or someone else has left it open. All you need is a cheap magnetic reed switch with a mini ESP32 board like a C3 or S3. The switch has two pieces, a magnet and a sensor, mounted separately.

Mount one half on the door and the other on the frame, power the board with a single coin-cell battery, and program it to sleep deeply when it’s not needed. You don’t need the door reporting a closed state all day. The board only needs to wake up if it detects the door open for a minute or more.

A Bluetooth proxy range extender

Locate devices and trigger automations using BLE

Building a Bluetooth proxy revealed all the chatty Bluetooth Low Energy devices in my home. But some still weren’t part of the network, like my electric toothbrush, lights, or window blinds. Whether I’m using a Philips Sonicare or an Oral-B Smart Series, it has Bluetooth to talk to a mobile app. Running a Bluetooth Proxy on an ESP32 lets the toothbrush act as a beacon to trigger bathroom-specific automations. Of course, the house gets smarter, not the toothbrush. It sounds ridiculous, but it’s a genuine “why not” project, thanks to the open-source Bermuda project, instead of just a “what if” idea.

A vibration sensor flags a finished wash cycle

Without touching the machine, know when the laundry’s ready

You don’t need a timer for repetitive tasks like knowing when a washing machine cycle ends. An ESP32 board with a vibration sensor can tell you exactly when that happens. You’re free from manually checking the wash cycle, and you’ll know the instant the laundry’s ready to come out. You can use ESPHome to write the firmware for ESP32 that watches for that movement and figure out when the machine has finished running. Of course, you might need to tweak the configuration so that you don’t get notified in between the wash and rinse cycles.

DIY smart speakers and a network streamer

You’ll need a specific ESP32 board or a few components to piece it all together

You don’t need to replace your old speakers with new smart ones just to control them from your phone. Plus, that’s a costly upgrade, and you can get similar functionality without emptying your wallet. The easiest route is the ESP32-A1S audio kit. It comes with line-in support, and flashing it with Squeezelite-ESP32 turns it into a DIY Bluetooth or network speaker. Set the ESP32 board as your streaming target, and apps like Spotify or your media server can send audio directly to your old speakers. Honestly, that’s a project worth undertaking before splurging on multi-room smart speakers.

An IR blaster replaces every remote in the house

Control the AC, TV, fan, and other systems that still use infrared

Home Assistant recently added infrared support, which has helped me bring my old TV, AC, and remote-controlled fan into Home Assistant. I’m currently building and testing a universal IR remote transmitter for my home. For that, I’m wiring up a couple of IR LEDs to an ESP32 through a small transistor on a basic hobby circuit board. I’m still working on placement so the transmitter points at the AC, TV, fan, and other electronics without obstruction. But that’s only half of it, because I need the ESP32 to learn to replay the received signal when I press a specific key on the remote, record that information, and relay it to the target device on command.

By storing that information, I can flash ESPHome firmware that easily triggers Home Assistant automations, like turning on the AC before I get home. You can use the same logic across several ESP32 projects to replace commercial products many people pay for, except the most common one is a universal remote you’d have to program anyway.

You don’t need a screwdriver and soldering kit

These five projects use an ESP32 to treat the appliance as a sealed unit, not something you need to open. A couple of these projects require some extra work to get the configuration right. But it’s still easier than reverse-engineering an appliance’s internals. None of them risk turning an appliance into a very expensive paperweight. If you’ve been meaning to make your home smarter, you can pair up an ESP32 with an old appliance without opening it up.