Archive for April, 2010

Corona RP8D1 receiver RSSI mod – cheapest OSD ever

When flying FPV, it’s essential to have both video and RC links perfect. One of these missing will result grounding effect, when your plane will loose control and gravity force will pull it to the surface much faster than you usually do. It’s easy to notice weak video signal – colors are disappearing, frames are out of sync, view is “snowy”.

It’s much harder to notice RC control link failures. Especially if link is digital. Receivers usually has LED, which indicates link quality. Glowing green led means that everything is ok, blinking or red led means link failures. This led is not seen during the flight, because receiver is hidden somewhere deep in the plane where all the servo wires come in and it’s more easy to protect from external damage.

I’ve modded my Corona synthesyzed 35 MHz frequency receiver RP8D1, so that I could see link failures in video signal. I’ve desoldered the LED from the receiver and moved to the front of the plane. 1 mA current was enough to light up white led with moderate luminance. To make led omni directional I’ve sanded it’s surface. This mod is very basic. Going further we can take analog RSSI signal from the receiver, buffer it and show it on led’s row or put into OSD. The we could see signal strength expressed in percent, not only blinking. But right now I think I’ll be fine with that.

We need to take paper and plastic protection from the electronics, and foam which covers the microchips.

Receiver is a small part so you need to be careful. The magnifying glass can help you.