Glen Akins' Tiny Traffic Lights Pack a Full-Color Display Into Each Aspect — with Wi-Fi Support, Too
This 3D-printed miniature traffic light set isn't your standard introductory electronics project!
Maker Glen Akins has created a twist on the classic beginner's project of a miniature traffic light — by replacing the red, amber, and green lights with full-color circular LEDs, housed in a 3D-printed scale replica of a real traffic light and its control cabinet.
"In this project, I build a miniature 3D-printed traffic signal and matching Wi-Fi-enabled controller cabinet," Akins explains. "The big twist is that each light on the signal is really a small round LCD permitting traditional traffic signals like bicycles, globes, and arrows as well as random images to be displayed — without disassembling or taking apart the signal."
A traffic light is a classic beginner's project for those venturing into electronics and industrial control systems: it's simple enough, given that a basic version can be built on a breadboard with just three LEDs and something to drive them, but requires an understanding of control logic in order to light things up in the right order.
Where a typical maker's traffic light would use LEDs — or, if you reach back far enough into history, small incandescent lamps with colored gels — Akins' uses a tiny 0.71" circular LED module from Waveshare, which is supplied with a cabochon lens to enlarge the image somewhat. While Akins' traffic light is working in its most basic mode, these simply display a solid color to mimic those of an actual traffic light.
That's not all they can do, though. "Each signal aspect is a little miniature display," Akins explains. "The Waveshare displays are small, measure only 18mm [around 0.71"] in diameter, and are mounted on a board that measures roughly 20×22mm [around 0.79×0.86"]. The 16-bit color displays are 160×160 pixels and use a GC9D01 controller with a SPI interface. They connect to a microcontroller using an eight-pin JST SH 1mm-pitch connector."
Like a real traffic light, the 3D-printed light box atop the pole only houses the lights themselves; the control logic is housed in a neighboring cabinet, inside of which is a Seeed Studio XIAO ESP32S3 microcontroller module with a miniature 2.4GHz antenna poking from the top. This is housed on a custom PCB that includes connectors for the displays and a buffering level translator from Texas Instruments to complete the electronics. "If you build lots of these," Akins notes, "you can use Wi-Fi and MQTT to synchronize their operation!"
The full guide, including source code, PCB design files, and 3D print files, is available on Akins' website.