Is software demodulation of 455 kHz possible on a Raspberry Pi 3

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Is software demodulation of 455 kHz possible on a Raspberry Pi 3

Software
Hi

I analyzed the codes of my remote control (for a heating system) manually using a non-demodulating IR receiver (TSOP98200) and a a Raspberry Pi 3. I noted that the remote control uses a 455 kHz carrier signal. FYI below the predicted .conf file.

The ultimate goal is to blast (not to receive). Nevertheless, to test, I like to confirm the derived codes by receiving them with mode2. The only demodulating IR receiver I could purchase is a no name receiver shipped from China; claimed to be an original TSOP9000 which appears to be not correct. Is there a possibility to use the TSOP98200 (non-demodulating) to test the codes? E.g., with a software demodulation?

Thanks for suggestions

A

********** zehnderheating.conf  (FYI)  **********

# zehnderheating config file  *** UNTESTED ***

# Observed from the remote control. Codes, carrier frequency and duty cycle
# examined using a RPi3 coupled with a non-demodulating IR receiver TSOP98200,
# recording with a resolution of appr. 100 nanoseconds.

# Brand:                       Zehnder
# Model no. of remote control: IRVAR 11
# Devices controlled by this remote:
#          Zehnder Heating Systems (http://www.zehnder-systems.com);
#          Likely similar codes are used by other appliances as Zehnder
#          representatives mentioned that the IR system is from a third party.

# Contributed by [hidden email]
#          (use 'lirc' as subject line to bypass my spam filter)

# Layout of remote control
#
# /-----------------------\
# |                       |
# |  +-----------------+  |   \
# |  |/\/\/\/\/\/\/\/\/|  |   |
# |  |/\/\/\/\/\/\/\/\/|  |   |
# |  |/\/\/\/\/\/\/\/\/|  |    > Display
# |  |/\/\/\/\/\/\/\/\/|  |   |  (bottom row: power level)
# |  |0 1 2 3 4 5 6 7 8|  |   |
# |  +-----------------+  |   /
# |                       |
# |                       |
# |   <--    -->  Enter   |   \
# |                       |   |  Buttons, see
# |                       |   |  notes below
# |  Manual Timer  Prog   |   /
# |                       |
# |                       |
# |                       |
# |                       |
# |                       |
# |                       |
# |                       |
# |                       |
# |                       |
# |                       |
# |                       |
# |                       |
# |                       |
# |                       |
# |                       |
# \-----------------------/
#
# Arrow buttons: change the preset power level; if the heating is on (rather:
#          the last signal was KEY_1 - KEY_8, thus the remote believes that
#          the heating is on), then the arrow buttons produce an IR signal:
#          the new power level. Also roles in programming mode.
# Manual button: sends the current preset power level (KEY_1 - KEY_8) if the
#          heating was off, or KEY_0 if the heating was on.
# Timer button: sends the current preset power level (KEY_1 - KEY_8), and 90
#          minutes later (time can be modified) KEY_0.
# Enter and Prog buttons: used to program the remote control; do not produce
#          IR signals.
# IR signals, according to the preset power level, are also sent when a
# programmed timepoint has been reached.

begin remote

  name          zehnderheating
  bits          8
  pre_data_bits 8
  flags         SPACE_ENC
#  eps           10
  aeps          68
  min_repeat    0

  one           30   650
  zero          30   830
# sequence: header plead pre_data pre data post post_data ptrail foot gap
  header        30  1000
  pre_data      0xB8
  post          30   460
  ptrail        30
# an arbitrary long space as nothing follows
  gap           100000

  frequency     455000
  duty_cycle    50

  begin codes
    KEY_0       0x0D   # switch heater off
    KEY_1       0x86
    KEY_2       0x95
    KEY_3       0xA0
    KEY_4       0xB3
    KEY_5       0xCA
    KEY_6       0xD9
    KEY_7       0xEC
    KEY_8       0xFF
  end codes

end remote

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Re: Is software demodulation of 455 kHz possible on a Raspberry Pi 3

Bengt Martensson-2
On 11/30/16 16:00, [hidden email] wrote:
> Hi
>
> I analyzed the codes of my remote control (for a heating system) manually using a non-demodulating IR receiver (TSOP98200) and a a Raspberry Pi 3. I noted that the remote control uses a 455 kHz carrier signal. FYI below the predicted .conf file.

Using lirc_rpi? Any modifications? Interesting. (Some years ago I once
tried a QSE159 on a RPi 1B and did not get it to work reliably).

> The ultimate goal is to blast (not to receive).

This should be straightforward, or is there a problem?

> Nevertheless, to test, I like to confirm the derived codes by receiving them with mode2. The only demodulating IR receiver I could purchase is a no name receiver shipped from China; claimed to be an original TSOP9000 which appears to be not correct.

??? Possibly you mean TSOP7000? There is a number of offers on EBay and
Aliexpress.

> Is there a possibility to use the TSOP98200 (non-demodulating) to test the codes? E.g., with a software demodulation?

The most convenient way to capure hight-frequency IR signals is the
CommandFusion and IrScrutinizer. To answer your question; I am not aware
of anything directly usable for this use case.

An interesting possibility would be to modify DevSlashLirc
(https://github.com/bengtmartensson/DevSlashLirc), preferably evaluating
the modulation frequency (possibly also the duty cycle) instead of just
disposing it. Would give nice possibilities in conjunction with
IrScrutinizer (which, starting at version 1.3, supports reading/writing
to/from /dev/lirc).

Greetz,

Bengt


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