HAVACOMM

PIC CHIPS PROGRAMMED FOR DIGITAL FEEDBACK SERVOS
HOMEOVERVIEWR/C AIRCRAFTROBOTICSOUR ADDRESS

As stated in the "overview" section, the normal PWT (pulse width tracking) TX/RX will not work with these servos.  It will take an entirely new data transmission scheme.  There is a diagram of this system in the overview.  I present schematics of a TX encoder and RX demux that we have flown with good success.  The TX encoder is an analog to digital converter using a PIC 16F873A with 8 A/D inputs.  Use the normal stick pots on a PWT transmitter as inputs.  This is not a true digital solution and I have designed a true digital stick assembly but we haven't mechanized one as yet.  The RX demux uses a 16F628 and a pair of opamps to square up the RX output and drive the PIC chip.  Programmed chips for these applications are available from Havacomm.  The latest program for the encoder and demux incorporate a checksum feature which prevents noise from driving the servos erratically.