IR Update

Today Sibille and I made some additional tests with the IR receptors, like we talked about in this recent post.

We used the AGC2 TSOP4856 receptor, as well as a LTE-R38381S-ZF-U emitter, with the same circuit setup for our previous tests described in this post.

The first thing we tested was whether we could overwhelm the receptor’s AGC by exposing it to an IR burst longer than the maximum burst length, which is 1.8ms for our receptor. 

With bursts of 3ms (on) and 100ms gaps (off), the receptor tended to be 10 or 20ms late in reacting to the end of the burst. When we switched to 20ms burst, we obtained similar delays. These burst and gap timings are approximately those a rotating receptor exposed to an IR source once per rotation would see. While exceeding the maximum burst length does introduce a slight delay, it is so small as to only result in our angle being off by a few fractions of a degree. So it seems we wouldn’t have any trouble with a continuous IR emission.

However, just in case it doesn’t go as well in practice, we also tested emitting 1ms burst and 1ms gaps. These would be acceptable timings for non-continuous IR emission. And without surprise, the receptor reacted very well with no detectable delays. So this would be feasible backup solution.

That’s all for today, we’ll keep you posted 🙂

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