3 Home Assistant projects to build multipurpose devices this weekend (Sep 18-20)

Published Sep 18, 2026, 6:00 AM EDT Adam has a degree in Engineering and has a life-long interest in technology. He has been writing for over a decade for various print and online publications, with a focus on consumer tech. He joined How-To Geek in 2024 while working at Pocket-lint. As well as being a long-term fan of Apple products, he also has a strong interest in smart home tech, running a Home Assistant server at home to automate all his smart home devices. He believes that the ideal smart home should work with minimal interaction from the user, with automations running as if by magic rather than requiring you to push buttons on a control panel. You can find more of his work on Muck Rack. My home is full of smart devices. My office desk alone is covered in different gadgets and sensors. With a little planning, you can reduce the number of devices around your home by combining several of them into a single device. Build a presence sensor, smart button, and status light Why have three devices when you can use one? This project started life precisely because the creator realized they were using three separate devices in their home office. Along with a dedicated presence sensor, they used a Philips Hue smart button and a Pico remote to control devices such as fans in the office. They decided to combine these devices into a single unit using an ESP32, a presence-sensing module, two physical buttons, and three LEDs. After a few iterations, they ended up with Scoopy: a tiny ESPHome controller you can place on a desk or hide away under a table to monitor presence, control devices, and even work as a Bluetooth proxy. Each button exposes single-press, double-press, and hold actions, giving you a surprising number of options from such a tiny device. You can set each LED's brightness independently and use effects to display different states. The creator has made the hardware, firmware, and STL files available on GitHub so that you can build your own Scoopy. If you like the idea but don't want to spend time on the build, you can buy a Scoopy directly from the creator's website. You can also buy the PCBA boards to get your build started. Add a display to a Bluetooth proxy Give your ESP32 a second job Credit: u/ZellFlix / Reddit One of the simplest projects you can do with an ESP32 is turning it into a Bluetooth proxy. There's ready-made ESPHome firmware you can flash, which allows Home Assistant to talk to Bluetooth devices that are otherwise out of Bluetooth range by communicating through the proxy. You can also use Bluetooth proxies with software such as Bermuda to give you room-based presence detection based on the location of your phone or watch. Presence tracking works best with multiple Bluetooth proxies placed around your home. If you're going to be putting a lot of ESP32s everywhere, it seems a waste for them to be doing nothing but acting as proxies. One Home Assistant user came up with a way to get far more use out of them. The idea was to connect a display to the ESP32, so that it can show useful information as well as work as a Bluetooth proxy. It uses a ZJY130I0400WG41 1.29-inch 128×64 CH1115 OLED display, built into a 3D-printed enclosure. The screen can display temperature and humidity data from Home Assistant entities, Wi-Fi signal strength, and the proxy connection status. The full instructions, including parts, wiring details, ESPHome configuration, and installation guide, can be found on the user's GitHub. Of course, you don't need to use the provided firmware; you can always build your own to make the screen display whatever you want. You don't even need to use the same hardware or design; you may prefer to use a different display and design your own housing. Make your standing desk track how long you're sitting Control your desk and monitor your presence Credit: Bill Loguidice / How-To Geek This is a project that I really love. I spend most of my workday sitting at my desk in front of a computer, and I constantly worry that I'm sitting too long. Being too sedentary has been shown to be bad for your health, and I'm always trying to find ways to ensure that I don't sit for too long. I have a presence sensor set up with a zone that contains only my office chair. When I sit in the chair, my presence is detected, and when I get up, the presence clears. I use this to monitor how long I'm sitting, with smart speakers nagging me to get up if I sit too long, and a Live Activity notification on my iPhone showing how long I've currently been sitting. I also have a standing desk which I use when I remember to. One Home Assistant user came up with a clever way to combine these two devices. If you have a compatible standing desk with an RJ45 port, you can control it remotely, using an ESP32 to send the relevant signals to the controller. The user then added an LD2410 presence sensor, which opens up a world of possibilities. The presence sensor can detect when you're in your seat, and via the ESP32, you can tell Home Assistant whether the desk is up or down. This allows you to track how long you're standing, how long you're sitting, and how long you're away from your desk. Unfortunately, my standing desk doesn't have an RJ45 port, so I've had to fudge together a less elegant solution. I stuck one half of a door contact sensor to the back of the desk and the other half to the wall at the exact height of the desk. When the desk is down, the sensor indicates the door is closed, but when the desk is up, the two parts separate, and the sensor shows the door is open. I can now track my sitting and standing time, even if I still have to control my desk manually. Make your smart home devices do more It's always nice to get more use out of hardware you already have. I added soil moisture sensors to my ESP32 boards so that my Bluetooth proxies can also tell me when my plants need watering. You may find you don't need to buy a brand-new device; you can often do more with those you already own.