I missed this one before, when it was announced at Electronica: the Uno SPE Shield, created by Arduino and Microchip working together. It turns out, though, that it wasn't available back then. And it ...

An Arduino Uno (CH340G clone) reads temperature and humidity from a DHT11 sensor and computes 10+ environmental metrics (heat index, dew point, enthalpy, humidex, vapor pressures, etc.), outputting ...

This is a DIY project to send sensors telemetry for a fraction of the weight and cost of the stock sensors. It adds support for several ESC telemetry protocols.