The maker community dropped a DIY Nixie‑Inspired ESP32 Clock Shows Time and Weather on a Budget on September 20, 2026, and the whole thing lives on a $40 bill of parts.
What makes this drop worth a second look is that the clock isn’t just a pretty face. It drives custom‑etched Nixie‑style tubes, pulls real‑time temperature from the OpenWeatherMap API, and ships with fully open‑source firmware on GitHub. In a world where a single‑digit price tag still nets a retro‑glow display, the project feels like a cheat code for hobbyists who want both style and substance without draining their wallets.
ESP32‑driven Nixie‑style clock adds live weather display
The heart of the build is an ESP‑32 WROOM‑32 module, the same chip you see in cheap Wi‑Fi‑enabled sensors. I wired the module to three 0.5‑inch Nixie‑style glass tubes that have been laser‑etched with numerals and a small “°F/°C” glyph. The tubes aren’t true neon‑filled Nixies, but the etched glass paired with a high‑voltage driver board (the HV5622 chip) gives a convincing retro glow while staying under 5 W of power.
Weather data comes from the free tier of the OpenWeatherMap API. After you snag an API key, the firmware contacts the service every ten minutes, parses the JSON payload, and updates the temperature digit in real time. The code uses the Arduino‑compatible WiFiClientSecure library, so the HTTPS handshake works out‑of‑the‑box on any modern router—whether you’re on AT&T fiber, Verizon Fios, Comcast Xfinity, or T‑Mobile’s 5G home gateway.
All of the parts—ESP‑32 module, HV5622 driver, three etched tubes, a 5 V / 2 A power supply, a few resistors, and a 3‑D‑printed enclosure—add up to under $40. I sourced the ESP‑32 from Digi‑Key, the driver board from SparkFun, and the tubes from a small batch on Aliexpress. Shipping to the US typically takes two to three business days, so you can have a working prototype before the weekend.
The firmware lives on a public GitHub repo (github.com/retro‑clock/esp32‑nixie‑weather). The repo includes a PlatformIO project file, a step‑by‑step build guide, and a ready‑to‑flash binary for those who just want to skip compilation. The license is MIT, which means you can fork, tweak the UI, or add extra sensors without asking permission.
What the clock means for you
First off, data usage is negligible. Each weather request is roughly 1 KB of JSON, so even if you’re on a metered AT&T mobile hotspot, you’ll burn through less than 5 MB a month. That’s well under the typical 10 GB cap most US carriers impose on prepaid plans, so you won’t see a surprise on your bill.
Second, the build sidesteps the usual “flash‑and‑forget” firmware traps. Because the code is open source, you can audit the Wi‑Fi credentials handling, verify that no telemetry is being sent to unknown servers, and even sign the binary with your own key if you run a corporate‑managed device. For folks who run BitLocker‑encrypted laptops at work, the same security mindset applies: keep the firmware on a USB stick, scan it with Windows Defender, and flash it only after a clean boot.
If you’re in a shared office that uses Microsoft 365 and Intune, you can push the compiled binary to any Windows 11 workstation that has the Arduino IDE installed. The process takes about five minutes, and you’ll end up with a desk‑friendly retro clock that never needs a battery swap.
How to build and flash the clock
- Gather parts. Order an ESP‑32 WROOM‑32, an HV5622 driver board, three 0.5‑inch etched Nixie tubes, a 5 V / 2 A power supply, a few 10 kΩ resistors, and a micro‑USB cable. Print the enclosure STL from the GitHub repo and print it on a 0.2 mm PLA printer.
- Assemble the hardware. Solder the driver’s high‑voltage pins to the tube pins, connect the driver’s logic pins to the ESP‑32’s GPIO 18, 19, 21 (the repo’s wiring diagram shows the exact mapping), and wire the power supply to the ESP‑32’s VIN and GND. I used a heat‑shrink sleeve on the high‑voltage leads to avoid accidental shorts.
- Set up the software. Clone the repo, open the project in PlatformIO, and edit
src/config.hto insert your Wi‑Fi SSID, password, and OpenWeatherMap API key. If you prefer the Arduino IDE, just openesp32_nixie_weather.inoand hit Upload. - Flash the firmware. Connect the ESP‑32 to your PC via micro‑USB, select the correct COM port, and click Upload. The board will reboot, pull the current time from NTP (pool.ntp.org), and start the weather loop.
- Power it up. Plug the 5 V supply into a wall outlet, and you’ll see the tubes light up with the current hour, minute, and temperature. Adjust the brightness by turning the potentiometer on the driver board.
I’d flash the binary first, then verify the Wi‑Fi connection in the serial monitor. If you see “Weather fetch successful” and a temperature value, you’re good to go.
Best settings to tweak after flashing
- NTP server: The default points to
pool.ntp.org. If your office uses a corporate time server (e.g.,time.windows.com), changeNTP_SERVERinconfig.hto avoid extra DNS lookups. - Temperature units: Set
USE_FAHRENHEITtotruefor Fahrenheit orfalsefor Celsius. The UI swaps the “°F/°C” glyph automatically. - Wi‑Fi reconnect interval: The firmware retries every 30 seconds after a drop. In a congested office Wi‑Fi environment, bump
RECONNECT_DELAY_MSto 60000 ms to reduce power spikes.
Frequently asked questions
How much does the whole project really cost?
All components total under $40 in the US, assuming you buy the ESP‑32 and driver from major distributors and the tubes from a single Aliexpress batch. Shipping is usually free for orders over $30.
Do I need a paid OpenWeatherMap plan for the API?
No. The free tier allows 60 calls per minute and 1 000 calls per day, which is more than enough for the clock’s ten‑minute polling interval. Just sign up, grab the API key, and paste it into config.h.
Can I run this clock on battery power?
Yes, but you’ll need a stable 5 V / 2 A supply. A high‑capacity USB‑C power bank works, though the high‑voltage driver draws a few hundred milliamps when the tubes are lit, so expect about 12‑hour runtime on a 20 000 mAh pack.
Is the firmware safe for corporate environments?
Because the source is MIT‑licensed and the binary can be inspected, you can verify that no telemetry is sent beyond the OpenWeatherMap request. If your IT policy requires signed binaries, you can rebuild the firmware locally and sign it with your own certificate before deployment.
What if the Wi‑Fi connection drops frequently?
The firmware already includes an auto‑reconnect routine. If you see repeated dropouts, try moving the ESP‑32 closer to the router, or adjust the RECONNECT_DELAY_MS constant in config.h to give the network more time to stabilize.
Final thoughts
Install the clock now if you want a retro‑glow desk accessory that never needs a battery swap and gives you live temperature updates for less than the cost of a coffee. The hardware is cheap, the firmware is transparent, and the data footprint is tiny, so there’s no downside to building it today.
