An ESP32-Powered Desktop Weather Display Solves the Problem of Empty Rooms with mmWave Radar

For technology enthusiasts and makers alike, one of the greatest joys of working with microcontroller projects is discovering that a fellow developer has already done the heavy lifting. This philosophy is at the heart of a popular new DIY project making waves online: a smart desktop weather display that not only provides real-time meteorological data and multi-day forecasts, but also possesses the situational awareness to know when someone is actually in the room.

The brilliant design offers a compelling alternative to constantly pulling out a smartphone, unlocking the device, and navigating through a dedicated weather application. Instead, all vital atmospheric information—from current conditions to hourly breakdowns—is presented at a glance on a dedicated desk accessory. Yet, this convenience has historically come with an inherent inefficiency: keeping an LCD screen powered on 24 hours a day, seven days a week, even when the room is entirely empty. To eliminate this waste without sacrificing utility, the creator of this open-source project integrated an mmWave presence sensor, ensuring the display springs to life only when a user is present.

A Weather Display That Knows When You’re Nearby

Keeping track of changing weather conditions is a daily ritual for many, particularly when deciding what clothing is appropriate before heading out into the elements. While smartphones have made meteorological data ubiquitous, dedicated desktop displays offer a frictionless way to check the forecast.

The device functions as a compact information hub, presenting local weather conditions alongside comprehensive hourly and daily forecasts, the current time, and additional metrics. By incorporating a responsive touchscreen display, users can easily swipe through different screens to access deeper meteorological insights without cluttering their main computer monitors.

However, the primary hurdle with any always-on desktop screen is power management and component longevity. Because a standard weather display cannot read its owner’s mind, developers typically default to leaving the panel illuminated continuously. This approach is far from energy-efficient and unnecessarily degrades the display over time.

The developer behind this latest build resolved the dilemma by incorporating an mmWave presence sensor directly into the custom enclosure. Unlike traditional infrared motion detectors that only trigger upon physical movement, advanced millimeter-wave radar technology detects subtle human presence—such as a person sitting quietly at a desk—ensuring the screen remains illuminated while someone is there to view it, and automatically dims when the workspace is vacated.

An ESP32 Powers the Weather Display

Rather than forcing builders to source dozens of disparate components and wire them together from scratch, this project leverages a streamlined hardware approach inspired by a recent showcase shared on social media. The build is anchored by a Freenove FNK0103S board, which serves as an all-in-one platform integrating an ESP32-WROOM-32E microcontroller as its central processing unit alongside a vibrant 4-inch LCD touchscreen.

Because the core processing power and display interface come pre-integrated onto a single board, the physical assembly process requires minimal wiring. The primary exception is the mmWave radar module, which must be connected to the main board. To ensure everything fit neatly inside a compact desktop footprint, the project creator de-soldered the preinstalled vertical pin header from the radar module and replaced it with a 90-degree header, allowing the components to sit flush within a custom-designed housing.

Financial accessibility is a major selling point for ESP32-based hardware modifications, and this project is no exception. The total cost of raw components required to replicate the desktop weather display is estimated at approximately fifty dollars, though builders who already possess certain spare parts or microcontrollers in their workshop inventories can complete the assembly for even less.

Radar Makes the Weather Display Smarter Than a Motion Sensor Would

The standout engineering choice in this build is the integration of the mmWave presence sensor within the enclosure. Capable of detecting human targets several meters away under optimal conditions, the radar technology represents a massive upgrade over standard passive infrared motion sensors typically found in basic consumer electronics.

In a desktop environment, traditional motion detectors frequently fail because users often sit relatively still while working at a computer, reading, or writing. A conventional motion sensor requires distinct physical movement to register occupancy, meaning a display tethered to one would repeatedly shut off while its owner was quietly seated nearby.

By contrast, an mmWave sensor detects the microscopic movements associated with human respiration and heartbeat, ensuring that a user sitting calmly at their desk remains recognized by the system. The display stays powered on as long as presence is detected within the zone, and only cuts the LCD backlight after a predetermined period of absolute vacancy. The moment a user returns to the desk, the screen instantly illuminates without requiring any physical interaction, button presses, or touch inputs.

You Can Use Open-Source Software to Build Your Own

Beyond the physical hardware and 3D-printed enclosure, the project’s software ecosystem is designed to be accessible to the wider maker community. The firmware retrieves real-time weather data over local Wi-Fi networks by querying the Open-Meteo weather API. Once booted, the touchscreen interface allows users to configure their wireless connection, input their geographic location, select their preferred language, and toggle between temperature measurement units.

Rather than requiring builders to write custom code from scratch, the creator has released the complete firmware online. Written in Rust using the ESP-IDF development framework for ESP32 devices, the software offers a robust and modern alternative to standard ESPHome configurations.

The project’s public GitHub repository provides the complete firmware source code alongside exhaustive assembly documentation and wiring schematics. Additionally, files for the custom 3D-printable enclosure have been published, giving makers everything required to fabricate the finished device.

Makers are also not strictly locked into this exact hardware stack. The underlying concept can be adapted using alternative prototyping hardware, such as a Cheap Yellow Display module running weather data sourced from Home Assistant via ESPHome, paired with a standalone presence sensor elsewhere in the room. Ultimately, this smart weather display demonstrates how integrating advanced environmental sensors can elevate a standard utility project into an intuitive, seamless addition to any modern workspace.