Code Bank: BS2/Sony Remote Control Interface
--------------------------------------------
The following program reads signals from a Sony Corporation entertainment
equipment IR remote control, displays them in the DEBUG window and
outputs the result as DTMF tones. Parts count is low, consisting of an
infrared receiver module, such as the Sharp GP1U58X, a remote control
unit and optional speaker output parts (piezo transducer and 10 uF
capacitor). See the BASIC Stamp 2 manual for speaker hookup.

The infrared receiver module for this project should, ideally, be one
that is set for a 40 kHz carrier frequency. However, the more common
38 kHz modules will work also. Some reduction in range may be apparent,
but the final result is functional nonetheless. The output pin of the
module connects to a Stamp I/O pin and you supply +5 volts and ground
to the other pins.

The remote control that you use may be either a Sony manufactured unit,
or one of the universal remotes that can be configured for Sony
entertainment equipment. This is important since we’ll be dealing with,
and programming for, a specific signal protocol.

With Sony’s SIRCS specification, a start pulse is initially sent to
indicate the beginning of a frame of data. This pulse is 2.4 msec in
length. Following this are seven bits of data, which represent the
instruction being sent. An additional five bits follow, signifying
the target device (TV, VCR, etc.). Data bits are sent with the least
significant bit first and the most significant bit last.

The Category data in this example is ignored. If you do want to make
use of it, the listing can be extended to store and decode the last
five bits of the frame in the same manner as the first seven bits.

'-----------
'IR2DTMF.BS2
'
'Copyright © 1999 by D.G. Roy
'
'reads IR data from a Sony remote control, using a 40 kHz IR
'module (eg: Sharp GP1U58X) connected to SIGLINE. Displays the
'result in the DEBUG window and outputs as DTMF tones.
'
'pin assignments
SIGLINE CON     2       'signal from sensor
SPKR    CON     8       'audio output line
'
'constants
FALLING CON     0       'used by PULSIN cmd
'
'variables
DSIG    VAR     BYTE    'output
LOWPART VAR     NIB     'used in SAYCODE
HIPART  VAR     NIB     'used in SAYCODE
'
'instruction data
ID0     VAR     WORD    'result storage from PULSIN
ID1     VAR     WORD
ID2     VAR     WORD
ID3     VAR     WORD
ID4     VAR     WORD
ID5     VAR     WORD
ID6     VAR     WORD
ST      VAR     WORD    'start signal
JUNK    VAR     WORD    'temp storage
'
'----------------
'Main Loop starts
'----------------
sigread:
        DSIG = 0        'initialize result variable
'get start bit
        PULSIN SIGLINE, FALLING, ST
'get seven data bits (LSB first)
        PULSIN SIGLINE, FALLING, ID0
        PULSIN SIGLINE, FALLING, ID1
        PULSIN SIGLINE, FALLING, ID2
        PULSIN SIGLINE, FALLING, ID3
        PULSIN SIGLINE, FALLING, ID4
        PULSIN SIGLINE, FALLING, ID5
        PULSIN SIGLINE, FALLING, ID6

'collect six category bits - but we don't do anything with them
        PULSIN SIGLINE, FALLING, JUNK
        PULSIN SIGLINE, FALLING, JUNK
        PULSIN SIGLINE, FALLING, JUNK
        PULSIN SIGLINE, FALLING, JUNK
        PULSIN SIGLINE, FALLING, JUNK
        PULSIN SIGLINE, FALLING, JUNK

'verify a good start bit - should be about 1200
        IF ST < 1100 THEN sigread       'no good
        IF ST > 1300 THEN sigread       'try again

'start bit is OK, so convert data bits - a high (1) should be
' about 600, a low (0) should be about 300 - we split the
' difference and say that < 450 is a low, >= 450 is a high

'convert the instruction data - start with MSB
        IF ID6 < 450 THEN DD5
        DSIG = DSIG + 1         'add binary one
DD5:    DSIG = DSIG * 2         'shift left
        IF ID5 < 450 THEN DD4
        DSIG = DSIG + 1         'add binary one
DD4:    DSIG = DSIG * 2         'shift left
        IF ID4 < 450 THEN DD3
        DSIG = DSIG + 1         'add binary one
DD3:    DSIG = DSIG * 2         'shift left
        IF ID3 < 450 THEN DD2
        DSIG = DSIG + 1         'add binary one
DD2:    DSIG = DSIG * 2         'shift left
        IF ID2 < 450 Then DD1
        DSIG = DSIG + 1         'add binary one
DD1:    DSIG = DSIG * 2         'shift left
        IF ID1 < 450 THEN DD0
        DSIG = DSIG + 1         'add binary one
DD0:    DSIG = DSIG * 2         'shift left
        IF ID0 < 450 THEN DDDONE
        DSIG = DSIG + 1         'add binary one
DDDONE:
        'display the result
        DEBUG   ?DSIG
        GOSUB   SAYCODE         'output as DTMF
'and start over
        PAUSE   45              'to debounce signal
        GOTO    sigread

'-----------
'subroutines
'-----------
SAYCODE:
'break up the code and output as DTMF tones
'works for 2 digit codes
        LOWPART = DSIG // 10    'modulus
        HIPART = DSIG / 10
        DTMFOUT SPKR,[HIPART]
        DTMFOUT SPKR,[LOWPART]
        RETURN
'-------------

If you're not going to use the speaker output, just delete the GOSUB
SAYCODE instruction and the SAYCODE subroutine.

With this program, you can determine the numeric codes associated with
each button on the remote. From there, its a simple matter to jump to
individual subroutines for specific robot actions.