Hey Ryuta,<br><br>Yes, we'd thought about PIR's. My understanding, and I'd be happy to be proved wrong, is that they are either 'on' or 'off', motion or no-motion. <br><br>And this case what we'd really like is to be able to detect motion but also depth (3d) so we can measure whether something is moving towards and away from the chimes with a proportional representation of force. Then ideally lateral movement too so, say, someone waves their arm from side to side that that could also be measured.<br>
<br>Tricky & challenging on such a lightweight machine, particularly with no GEM, but I guess that's also part of the fun:)<br><br>Many thanks for your suggestion though.<br><br>All the best,<br><br>Julian<br><br>
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