At some point, the ESP32 stopped being just a cheap microcontroller I kept around for experiments and started becoming the answer to a lot of annoying little problems around my house. I'd put together a display to show information, build a sensor somewhere else, configure a board with a microphone, and suddenly the proprietary hardware around my house started to look more and more unnecessary as time went on.

That's not tsay that every ESP32 project is worth building. Plenty of them are fun for an afternoon and then end up in a drawer. The ones that stick are the ones that replace a real product with something cheaper, more local, and easier to bend into the shape you actually want.

There's an obvious catch, though, which makes this less viable for just anyone. You need to be comfortable with ESPHome or C programming, likely Home Assistant as well, and even 3D printing in some cases, along with the willingness to engage with some trial and error when the hardware doesn't behave. But if you're already in that world, these are the ESP32 projects that make the most sense to build instead of buy, and they're all ones that I've built in the past.

Ring and Nest doorbells

It's rougher, but it keeps the footage at home

Smart doorbells are useful, but the cloud side of them is much harder to love. The camera is useful, the button is useful, and the notification is useful, but paying a monthly fee for a cloud-connected camera at your front door feels less appealing once you realize how simple the core function is. My local-first Ring Doorbell alternative gets surprisingly close with an ESP32-S3-EYE, or an ESP32-S3-CAM-style board, an OV2640 camera module, and ESPHome.

It streams MJPEG video at 1024x768 and 10 FPS, which is enough for a doorbell camera, and the button feeds an event into Home Assistant. From there, Home Assistant can play a chime, store a snapshot, send a notification, or do whatever else you want it to do. Paired with a local LLM that has vision capabilities, you can have it automatically identify who or what is in the camera frame at a given moment.

It isn't as polished as a Ring or Nest doorbell. I had to keep the frame rate sensible because the camera could get worryingly hot, and a permanent build would want a better enclosure, maybe a PIR sensor, infrared lighting, and possibly Power over Ethernet. But the basic function is there: camera, button, chime, snapshot, and no monthly fee.

Smart clocks

ESPHome makes a cheap LED matrix surprisingly useful

Commercial smart clocks can cost far more than they should for something that mostly shows the time, dims at night, and maybe talks to an app you didn't ask for. My $15 ESP32 smart clock is a simpler version of that idea, built from an ESP32 development board and four daisy-chained MAX7219 LED matrix modules.

The ESP32 handles Wi-Fi, time synchronization, and ESPHome, while the MAX7219 panels provide the display. I designed and printed an enclosure in Onshape, powered the whole thing over USB-C, and used ESPHome to define the display, brightness controls, night mode, and a second page for text pushed from Home Assistant.

That second page gives it room to grow. It can show the time, dim itself at night, and receive text from Home Assistant, but I can also add a buzzer, a temperature sensor, or a different display page later. After I wrote that article, I actually added live bus times for the bus stop near my home, which has been pretty useful to have. It won't feel like a finished consumer device unless you spend more time on the enclosure, but for a few hours of work, it does exactly what I need.

Home lab control panels

The ESP32-P4 is much closer to a small appliance than a toy

Managing a home lab from browser tabs works, but it gets old quickly. Proxmox in one tab, a NAS dashboard in another, Home Assistant somewhere else, and maybe a terminal session on top is fine when you're sitting at a desk. It's worse when all you want to do is glance at a status screen or tap a button to restart something simple.

My $60 ESP32 touchscreen home lab dashboard solves that with an Elecrow CrowPanel Advanced 10.1-inch ESP32-P4 display. It runs ESPHome, uses LVGL for the interface, and pulls its data through Home Assistant. I built pages for NAS status and controls, Proxmox VM management, and a general system overview with quick actions.

A tablet on a wall can do a similar job, and for some people that's still the easier answer. But a purpose-built panel boots straight into its purpose, doesn't need a browser left open, and isn't constantly trying to be a general-purpose device. If your home lab already runs through Home Assistant, an ESP32 touchscreen can become the control panel the commercial smart home market keeps trying to sell in a much more locked-down form.

Meeting status lights

A calendar entity and a cheap screen are enough

Working from home creates a very specific problem: people in the house can't always tell when you're genuinely unavailable. You can buy meeting lights and status indicators for this, but the actual requirement is simple. Something outside the room needs to know when your calendar says you're busy, and it needs to show that clearly.

The ESP32 on-air display does that with a WT32-SC01 Plus, though any cheap ESP32 display that works with ESPHome should be enough. Home Assistant pulls in the calendar, exposes the current event and timing data, and template sensors clean that up into values the display can use.

The ESP32 screen just redraws based on the sensors it receives. If a call is live, it switches to "On Air." If not, it can show the next meeting for the day. It replaces a paid office gadget with hardware cheap enough that you don't need to overthink it, as long as your calendar is already available to Home Assistant.

Smart desk dashboards

It gives you the day's useful bits without another glowing screen

Desk dashboards are everywhere now, whether they're sold as calendar displays, smart home panels, or productivity gadgets. I get the appeal, but I don't always want another backlit screen sitting in front of me. My color e-paper productivity buddy is closer to a passive noticeboard that happens to be networked.

The build uses a XIAO ePaper setup with the EE04 driver board, an ESP32-S3, and a Spectra 6-color E Ink display. It shows the things I care about during the day: my next work call, tasks, weather, and a few hours of forecast data. Physical buttons let me switch between a work page and a weather page, which makes it feel less like a static printout.

Color helps more than I expected. E-paper still has that low-power, paper-like look, but red and green accents make important information stand out without forcing me to read every line. The trade-off is refresh speed, so this isn't the display for animations or live charts, but it's a great fit for a desk status board.

Echo and Nest speakers

It does less out of the box, but it belongs to you

Voice assistants are hard to replace because the polished versions are cheap and good enough for basic tasks. The problem is everything around them: cloud processing, account tie-ins, changing behavior, and hardware you don't really control. That's why my ESP32 voice assistant projects are among the most satisfying replacements here, even if they're also among the least plug-and-play.

My ESP32 voice assistant with a 3D printed home and GLaDOS's attitude uses a ReSpeaker Lite with ESPHome, Home Assistant, Whisper for speech-to-text, a locally hosted LLM for responses, and Piper for text-to-speech. I also put it in a 3D-printed enclosure so it looks like something that belongs on a shelf rather than a bare board with a speaker attached.

That setup replaced my Echo and Nest devices because it integrates better with the smart home I actually use. It does fewer things out of the box, but it doesn't send my voice to a third-party cloud, and I can change how it speaks or what it can access by editing my own configuration. My ESP32 display voice assistant with emotions takes the same idea in a more visual direction with XiaoZhi on an ESP32-P4 display, where the device handles audio, display, and interaction while server-side components handle the AI work.

Branded smart home sensors

The boring replacements are often the most useful

The ESP32 projects that stick around aren't always the flashiest ones. In my case, replacing half my smart home with ESPHome devices started with a simple temperature and humidity sensor. An ESP32, a calibrated DHT11 (or the more accurate BME280), ESPHome, and Home Assistant were enough to get local room data without opening the Alexa app or relying on a branded sensor.

That spiralled quickly. Temperature sensors, vibration sensors, noise sensors, small displays, e-paper panels, and voice interfaces all become variations of the same idea: a cheap board, a specific input or output, and local control. Once you realize how easy it is to define a sensor in ESPHome and have it appear in Home Assistant, the commercial smart home aisle starts looking a lot less magical.

This is probably the least glamorous replacement on the list, but it's the one that changes the most day to day. Branded sensors can be expensive, depend on vendor integrations, and break when an API changes. An ESPHome device still needs maintenance, but when it breaks, it's usually your YAML, your wiring, or a known ESPHome change you can actually inspect.

There's something for everyone

None of these projects are universal replacements. If you want something that works immediately, looks professionally finished, and comes with support, the commercial product is still the easier answer. There's nothing wrong with paying for that convenience, especially when the thing you're replacing touches your front door, your schedule, or your home automation.

But the ESP32 is very good at replacing products whose actual job is simpler than their branding suggests. A button, a camera feed, a clock, a dashboard, a calendar status light, a sensor, or a voice endpoint can all be built locally with hardware that costs far less than the polished retail version. It won't always look better, and it won't always be easier, but it can be yours in a way most smart gadgets aren't.

For me, that's been enough to keep building them.