Re: TI-H: IR Link
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If I may input a comment or two...I've been looking into Ir link stuff for a
while now, and this is what I've come up with.
I've located two different Ir transceivers, both are very small, low power
and could be mounted inside the calc and run off calc batteries. The first
transceiver is one that can be programmed to conform to any of the Ir
formats; even TV Ir. The second, is just Ir standard. The only external
circuits required are, the first needs an external clock and Tx/Rx LEDs; the
second needs no external parts, no clock; the LEDs are built in.
The base line Ir standard is a 1 in, a 1 transmitted. No modulation is
done. All the other Ir formats do so sort of modulation before transmitting.
The problem with both of these is they have one Tx and one Rx line.
Software would have to be written that would change the way the TI sends
data packets out and into the link port.
Another idea I've looked into is very close to one that has been mentioned
on this string. This idea would be to use hardware instead of software.
The transmitter would use two 566 VCOs, tuned to two frequencies. These
freqs would be OR'd together at the Tx LED. The receiver would use two 567
Tone Decoders, with their out puts going to the respective link port wires.
Both calculators and computer would need the transmitter/receiver.
The big problem with this hardware scheme is both power and size. Using a
566 timer would help with the power part. But the size part is not good.
Where do we put the batteries and circuit card. Having an Ir interface in a
box that you have to plug into your calc kind of defeats the purpose.
So, I like the first approach, where software does all the work and the
hardware fits in the calculator. I can do hareware, but not the software
and I have the transceivers in hand...What do you think?
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