Re: "blue duo" remote for FDM DUO

Giovanni Franza

Hi Bill,
starting from the end: better continuing in public: as a reference if other interested.

HC05 is fine, I don't know cable TE119, on this we discuss later
enable_uart=1 in /boot/config is ok
core_freq=250 is not needed

serial port is /dev/ttyAMA0
now the problem could be that serial line could be used by login daemon, so you have to disable:
no console= referring to ttyAMA0

HC05 should be wired to GPIO14/15 ( pin 8 and 10 of J8 header )
pin 6 (GND) to HC05 gnd
pin 8 (GPIO14) to HC05 RX data
pin 10 (GPIO15) to HC05 TX data
pin 4 (5Vcc) to HC05 Vcc
to setup connect pin 2 (5Vcc) to HC05 EN (or KEY)

The first thing to do is:
connect GPIO to the HC05

Power up the RPI, launch cutecom, set cutecom to
/dev/ttyAMA0 baud rate of 38400, 8 bit, 1 stopĀ  bit, no parity, and command terminated with CR LF
and press, on the keyboard the Key "A" and, then, the key "T" then CR and LF

HC05 supports a subset of the extended AT Hayes command set,
reading A from the serial it recognize the speed and reading the T it recognize the parity
and then it has to answer "OK" in response to "AT"CRLF

If you obtain this ok then you have all the important things.

To program the HC05 you have mainly to be sure that the speed is 115200
but also you wouls be sure that the HC05 is in slave mode anche the name is "BLUEDUO" and to set your password.

The commands are:

AT+ORGL followed by CR and LF resets the module
the answer must be OK
AT+NAME=BLUEDUO followed by CR and LF sets the name to BLUEDUO
the answer must be OK
AT+PSWD=2357 followed by CR and LF sets the password to 2357 (if you do not do this the default password is 1234)
the answer must be OK
AT+UART=115200,0,0 followed by CR and LF sets the speed to 115200, stop bits to 1 and parity to none
the answer must be OK

If you obtained all OK the work is done: disconnect HC05 EN (or KEY) pin from Raspberry PI, and disconnect the BT module that is programmed.

To test you could use cutecom, but you have to set to 115200 bit.

You can re program your HC05, redoing the step from connection on the (powered off) Raspberry.

It could be that, at a certain point, someting goes wrong and you do not have the "correct" results: please let me know at what point the things goes wrong, so we can make some verifications and corrections.

Have fun,

Giovanni - HB9EIK

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