RSSI

9 Articles

Super Simple, Super Cheap FPV Drone Tracking

May 4, 2018 by 20 Comments

What’s more disruptive to the drone first-person view (FPV) experience than dropouts in your video feed when you’re in the middle of a race? Probably nothing, and there’s probably also not much you can do about it. Or is there? Might a simple tracker based on RSSI help keep your video signal locked in?

Honestly, we’re not sure it would, but we think it’s pretty nifty to see [FlyerFpv]’s tracker following his drone around. The idea is simple and uses the full-diversity FPV receiver he already has. Diversity receivers constantly monitor signal strength from multiple antennas to determine which one to listen to, which improves reception quality. [FlyerFpv] sends the RSSI outputs to analog inputs on an Arduino which drives a servo to keep the signals as close to each other as possible. The Arduino and the DC-DC converter needed to power it fit nicely inside the receiver case with no modifications, which is a nice touch. With a 3D-printed servo mount and some fancy directional antennas, the setup keeps pretty good track of his drone now. See it in action below.

Sure, the response could be snappier, and we’d love to see another receiver and servo added to track pitch as well as yaw. For a first pass, we think it’s great, but [FlyerFpv] should enjoy it while he can in case AI takes over our flying fun soon.

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Simple Scanner Finds The Best WiFi Signal

April 21, 2017 by 8 Comments

Want to know which way to point your WiFi antenna to get the best signal? It’s a guessing game for most of us, but a quick build of a scanning WiFi antenna using mostly off-the-shelf components could point you in the right direction.

With saturation WiFi coverage in most places these days, optimizing your signal might seem like a pointless exercise. And indeed it seems [shawnhymel] built this more for fun than for practical reasons. Still, we can see applications where a scanning Yagi-Uda antenna would come in handy. The build started with a “WiFi divining rod” [shawnhymel] created from a simple homebrew Yagi-Uda and an ESP8266 to display the received signal strength indication (RSSI) from a specific access point. Tired of manually moving the popsicle stick and paperclip antenna, he built a two-axis scanner to swing the antenna through a complete hemisphere.

The RSSI for each point is recorded, and when the scan is complete, the antenna swings back to the strongest point. Given the antenna’s less-than-perfect directionality — [shawnhymel] traded narrow beam width for gain — we imagine the “strongest point” is somewhat subjective, but with a better antenna this could be a handy tool for site surveys, automated radio direction finding, or just mapping the RF environment of your neighborhood.

Yagi-Uda antennas and WiFi are no strangers to each other, whether it be a WiFi sniper rifle or another recycling bin Yagi.  Of course this scanner isn’t limited to WiFi. Maybe scanning a lightweight Yagi for the 2-meter band would be a great way to lock onto the local Ham repeater.

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