Ir Sensor

[seph]

http://michaelv.org/calc_mods.php#ir

Does this actually work, and can it be made with a standard (non SE) TI83+?

[DigiTan]

I'll have to answer with a resounding "no" -- at least from a hardware prespective. Dispite popular myth, direct-connecting IR LEDs to a link port will not work--it's just not that simple. The reason is because the signal needs to be filtered and amplified if you want your calc to know data from noise, which isn't done in the michaelv version.

A more proven design like Sami Khawam's PIC-based IR link would work much better under these conditions. (Actually, he sort of refutes the michaelv design in his FAQ but never mentions it directly). It uses something very similar to Radio Shack's filtered IR detectors (#276-640), verses simple LEDs. The chemical filtering creates a much narrower IR passband which is good for filtering noise from indoor lighting and other heat sources. It also runs on an electric filter which lets it reject any signal that doesn't ride with a 38kHz carrier, filtering out all kinds of noise-makers. It works for all Z80 models (TI-82 thur TI-86), and may work for more advanced calcs as well.