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This is an inexpensive wireless receiver/transmitter combination for quadcopters (or any rc toy) using esp8266 modules.

........................you          your quadcopter ............

+------+            +-----+          +-----+              +-----+
!      !----PPM---->!     !          !     !-----PPM----->!     !
!Remote!            ! ESP !<--wifi-->! ESP !              ! FC  !
!      !<--Serial---!     !          !     !<---Serial----!     !  
+------+            +-----+          +-----+              +-----+

PPM input is transported using raw packets (no wifi peering or binding needed). PPM input/output is supported by most remotes and flight controllers. An diy ESP8266-based transmitter is small enough to fit into the transmitter compartment of the turnigy 9x remote.

You should use ESP-07 (or similar) modules that have an connector for an external wifi antenna, ESP-01 is only suitable for LOS flying range-wise.

PPM In/Out is interrupt based (timer0), raw wifi packet reception callback based, all the hard work is done, so there is lots of playroom to add your own stuff to the code. I'm using this to fly a gyrocopter and 250 quadcopter.

The wifi packet type for the PPM data is a beacon packet (with an unused MFIE tag), so you should be able to see if the transmitter is transmitting by scanning for wifi networks on your phone or tablet.

Around 600m in nature with external wifi antennas, about 100m with chip antennas. About the same as the Turnigy 9X 8C V2 that broke on me and is the reason for this project.

• Make more secure, channel hopping?
• showcase uses on codeninja.de?