This Handheld Wi-Fi Signal Strength Meter Packs a Servo to Drive a Physical Dial Gauge
Inspired by the "spirit boxes" of film, this analog gauge lets you know when you've strayed from the path of strong connectivity.
Pseudonymous maker "CrazyScience" has built a Wi-Fi signal strength guide with a difference: it moves a physical dial on a gauge to let you know when you're straying from an access point's sweet spot.
"I have always been using many [smartphone] applications to check my Wi-Fi speed, the process is time consuming and it's not that accurate(in terms of real time)," CrazyScience explains of the need for a dedicated tool. "So I wanted [a way] to visualize the Wi-Fi that [works] in real time! I'm not sure if the spirit boxes work (like you see in movies). But my Wi-Fi meter will definitely work!"
The meter is built around a Lolin Wemos D1 Mini, a compact and low-cost microcontroller board built around Espressif's ESP8266 microcontroller — which includes an integrated single-band 2.4GHz Wi-Fi radio. To this, CrazyScience connected a WS2812B addressable RGB LED and a micro hobby servo.
It's the servo that gives the signal strength meter its physical meter: a bent piece of 3D printing filament is attached to the servo and calibrated to point at a hand-drawn gauge depending on received signal strength. As you move further away from the Wi-Fi access point, or otherwise experience a drop in signal strength, the pointer rotates — and rotates back again as you correct your position for maximum Wi-Fi quality.
While the gadget can be used entirely on its own, it also provides a self-hosted web page which duplicates the gauge's display — meaning it can also replace smartphone-based signal strength apps, too.
The project is documented in full, including source code, on Instructables.