Brushless motor and esc may become overheated during flight. Overheated component can result in abrupt falling out of sky in case of multi rotor machine. This may involve fatal consequence as well. It is not easy to assess in advance how the combination of particular brushless motor, ESC, propeller and weight of machine will behave with some environmental condition (ambient temperature, wind, air pressure, etc.).
Therefore it is good to know the temperatures of brushless motor and ESC along with APM MAVLink information during flight.
MAVLink information and additional temperature sensors are displayed on FrSky Taranis using Arduino. This solution uses Arduino to convert MAVLink telemetry protocol to FrSky smart port protocol. Arduino plays a role of bridge between the telemetry UART port of APM and smart port of FrSky radio receiver (X8R, X6R, X4R). Communication between Arduino and MAVLink source (APM) is implemented via hardware UART of Arduino. FrSky smart port is connected to a digital pin that SoftwareSerial drives. Besides MAVLink, Arduino provides 2 temperatures for smart port. Temperature is measured with
NTC termistors. NTC: 10K 5% Thin Film Thermistor B25 3380, R25 10k. One of 2 NTCs is placed on the bottom of motor, another is glued on the top of ESC. MAVLink and temperatures are displayed on FrSky Taranis LCD using Lua scripts. There are 4 new telemetry screens: MAVLink formation with actual temperatures, MAVLink message, battery condition, temperature
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