fish@ihu1g.UUCP (Bob Fishell) (05/24/84)
(oo)
I'm trying to put together a system controller for my stereo
system, which contains no fewer than 5 signal processors in
addition to the amplifiers and tape decks, tuner, CD player,
turntable, etc. I've seen the ones made by AR and dbx, but
neither is exactly what I want, so I thought I'd roll my own.
The problem is, I want remote control, and I'd like to go
wireless. Lots of TVs, VCRs, CD players, and the like
come with these, but I'd like to know if any outfit sells
a multi-function remote control that can be used in custom
circuits. Four functions would be enough, but 10 or 16
would be even better. I'm envisioning a calculator-style
or hexadecimal keypad transmitter with a reciever that
puts out BCD or 1-of-16, etc. Anybody seen anything like
this? I've looked through the ads in the electronics
mags, but I can't find anything like what I want.
Thanks in advance to whomever...
--
Bob Fishell
ihnp4!ihu1g!fishpiety@hplabs.UUCP (Bob Piety) (05/25/84)
National's LM1871 & LM1872 chips can be used for a radio or IR remote control. Check out their linear data book for app notes. Bob
ksbszabo@wateng.UUCP (Kevin S. B. Szabo) (06/06/84)
I'm just back from holidays (actually marriage) so I hope this info isn't redundant. Motorola has a chip set MC14457 and MC14458 which are a transmitter and receiver pair in CMOS technology. There features are : Ultrasonic/Infared remote control Selection of 16 channels with a single keypress, 256 with two presses One analogue output, 6 bit resolution. This is obviously a TV controller, with certain keys increasing the analogue output and others decreasing or setting it to zero (i.e. Mute). Anyway, you can do what you want with the digital channels, i.e. probably run them into a few counters and then into some DAC's to control the audio. Caveat: I haven't used these chips so I can't personally vouch for them. Apparently the hardest part in building the control is the preamp for the IR photodiode. It has to be very sensitive, ignore room lights and direct sunlight and also any nearby electronic interference from the digital decoding circuitry. Anyway, have a look in the Motorola Cmos DataBook. Kevin -- Kevin Szabo watmath!wateng!ksbszabo (Elec Eng, U of Waterloo)
smb@ulysses.UUCP (Steven Bellovin) (06/06/84)
Speaking of remote controls -- do these jobs tend to have different frequencies or encodings, so that one can safely have two in the same room?
dya@unc-c.UUCP (06/07/84)
References: ulysses.872
No, but they are encoded differently with a protocol so that two remotes
of the same manufacturer won't interfere. For example, the remote control
for the Zenith System III and the Zenith Z-TAC cable descrambler box have the
exact same hardware; but the System III contoller won't activate the Z-TAC
box and vice versa. Software, I suspect.
dyadya@unc-c.UUCP (06/07/84)
References: wateng.1071
For the IR preamplifier, dig out a copy of Plessey's Radio and Communications
IC book. Then buy your chips from Motorola -:). Seriously, you should be able
to use the MC34074A operational amplifier for this. If you can finagle a
General Insturments hand unit for their Jerrold 400 cable box (this should not
be too hard) then whatever comes out of the preamp is (Probably) ASCII, 50
baud. (No flames about ripping open my cable box, I own it.) They use something
stamped "Motorola" which has the right number of pins for a 68**0*()*/* (for
you Intel folks, that's one of a zillion 6805 variations) but of course the
GI part number. Pop in the ACIA (etc) of your choice and you are in business.
It looks like a 6805S2 from where the data goes (from the IR preamp).
As for getting it to ignore room lights, etc. just use a piece of glass
which has been treated to pass IR but sharply attenuate the rest. These are
common. GI uses red plastic...Kevin's right, though, about getting the
vacuum cleaner's arcing commutator near this, though. I think that's why
the picked the low baud rate for the transmitter.
I once had delusions about doing this for a satellite receiver, but found
that too much tweaking is required with those cheap home units to make it worth
while.
dyajeh@ritcv.UUCP (Jim Heliotis) (06/11/84)
All I can say about unique frequencies is that I have a (made-by-Sony)
Zenith VCR, and once rented a Sony VCR, and they both responded identically
to my remote control.
...so what's it going to be? The football game or Mr. Rogers?
)-: ?
Jim Heliotis
{allegra,seismo}!rochester!ritcv!jeh
rocksvax!ritcv!jeh
ritcv!jeh@Rochesterfish@ihu1g.UUCP (Bob Fishell) (06/12/84)
Yipes!
I seem to have created a monster...all I wanted to know was whether
I could get a preassembled IR transmitter and receiver to be used
in a home-brew audio project. Anyway, thanks to all of you who've
sent information about the various chip sets on the market. I was
hoping for a complete assembly, but at least now I know I can build
one from scratch, if needed.
--
Bob Fishell
ihnp4!ihu1g!fish