More "Universal" IR Remote Control

[N_Cook]

Video projector without an IR R/C , originals or substitute not available
and cannot access the presets.
Setting a One-for-all so-called universal, URC 3445 in search mode ellicited
nothing in TV/VCR/Sat/DVD sub sets, as usual. What is not specifically
stated in the URC manual is after setting in search mode , why you press
power button, and then + to advance through the presets in the firmware, to
send power on/off codes.
I forgot to press Power in the DVD subset sequence and instead of
transmitting variously coded Power codes it must have sent various + codes.
Anyway on DVD code 1928 the "Keystone +" box popped up on screen. The "-" ,
Power , or no other button worked in this DVD subset mode. I intend getting
into the URC, remove ceramic resonator, and putting about 2V rms of sig gen
around the resonant frequency (done this before on a different URC) and see
if that opens up more buttons , set on 1928.
Failing anything more useful from that, monitor that "+" sequence on digital
storage scope should give the "50 KHz" pulse rate , coding clock rate and
combined model+code sequence for "+".
Then something like this circuitry of settable clock + CMOS switch settable
PISO shift register for model code (HCT165 ?) / settable delay SR (4557?) /
another settable PISO for buton code / gating a settable "50 KHz "
oscillator / IR diode / ( learnable remote for regular use ).
Changing switch settings for the button PISO from the known working "+" code
to the missing ones particularly for MENU and ENTER functions in particular
.. Any flaws in this potential hack, as only thought experiment at the
moment?

ps , for the UK anyone know what is the cheapest souce of very basic
learnable remote controls?

 

[N_Cook]

fell at the first hurdle - the resonator in the one-for-all is 3 pin , 2
element? 8MHz resonator

 

[N_Cook]

The default, not in vol or menu mode , for + is the keystone + function
The code , in the manual , for that via the RS232 link is
start code ascii 0 0 ,function r06 ,and end code (return)
so HEX
30 30 72 30 36 0D
I wonder if any of that is reflected in the IR code for +

 

[Bob F]

Perhaps make and model might be made available?

And searching for that in JP1 code lists might find the codes to be programmed
into a JP1 programmable remote.

 

[N_Cook]

And searching for that in JP1 code lists might find the codes to be programmed
into a JP1 programmable remote.

Not listed there , but that would have spoilt my fun.
I've just captured that "+" code on a learning remote so I can play it at
will , rather than counting 105 steps on the URC . Whatever the code was the
URC sent is not stored in the URC as the same code.
So I've "learned" the 2 , to see what the difference is also.
Will have a look on a straight scope for the 2 basic timings and then DSO to
read the 0s and 1s.
I looked into the learner to see if its possible to change the resonator to
a much lower frequency to actually observe/count/time the code by swapping
IR LED to visible LED. But an 8 MHz 2 element 3 pin , I've previously done
that when I had no DSO access.

Even going down the LIRC route you still have to crack into the IR receive
hidden decoding to get started, if no listing. It would be nice to have a
general "all codes" sniffer , I was just lucky with this attempt this time .
Anyone know, if you had access to the uP of the device in question and could
put a nanoamp monitor or something in a supply line, whether you could zero
in , like cracking a combination lock

 

[N_Cook]

I thought I'd better try the learned code on the projector, but nothing. It
is all now making a bit of sense though. With the projector I was not
covering the IR LED with the other hand. With OFA 23 button push on its own
, isolated, produced no OSD. It now explains why I could only preset with
code 1004 and advance 23 steps as somewhere in between was a pre-code . By
elimination , by selective covering of the LED , it is step 6.
So programmed in 2 codes in the learner, "6" and "23". It now works with the
projector bringing up the Keystone + on OSD.
Codes are not sequential in the OFA , preset to 1004 and +6 pushes reads out
as code number 631 and 1004 + 23 reads out as 1928

So I thought set with learned "6" and run through all the OFA codes. If
there is a time-out reset between 6 and 23 it is greater than 2 minutes, as
I timed it . In TV and SAT codes something resets the 6 , in less than 2
minutes so something active in the wrong sense , but did not ellicit any
other OSD responses.

If the "23" preceeded the "6" in the OFA listing then I would not have seen
the keystone response , although (not specifically stated in the manual) you
can multi-step down as well as up.
Will set up scope and DSO tomorrow. I will also try learned 631 code and OFA
going down all its code banks to see if it hits something active before
those lurking reset codes.
Lools like a more general hack routine is to use 2 URC , preferably the same
model, for these 2 stage coded systems and automate the button pushes
electronically

 

[N_Cook]

I aalso powered-down the projector to reset any erroneous codes in the
system and then checked from fresh , that the learned 6 and 23 worked still

 

[N_Cook]

One-For-All remotes- some have reassignment values for the different
device keys. And, for instance, the TV subset will not accept codes or
generate codes outside the TV code database. Check and reassign the
device keys for the proper device. Usually by:
device key
set
enter reassignment code (992)
target device key

JR

The O-F-A is just a tool in this experiment, a means to an end

Looks as though the "23" precode of a Pioneer DVD is HEX
FFF0289294AA8
and the "6" code of a Samsung DVD is FF01
Perhaps a lot of the "23" one is ignored as junk and only the AA8 or 4AA8,
say , acts as precode.

So now to build a PISO with a bank of dip switches to code around the FF01
for the various functions (hopefully) and retain the learned code of the
"23" and use both to set up a workaday learner rather than fancy one with
LCD touch screen liability

Now where to find some of these basic Chunghop learning remotes
http://www.hot-buy.co.uk/electronics-accessories/general-tv-vcd-dvd-recorder
-new-learning-remote-control.html
from a genuine co.uk rather than the co.hk or whatever, of that supplier.
"If something is too good to be true, then probably not true" but then
perhaps a non-CC gamble on 3 off of them is not so tough