<html><body><div style="color:#000; background-color:#fff; font-family:Courier New, courier, monaco, monospace, sans-serif;font-size:12pt"><div><span class="tab"> </span><span>I must say I'm astonished that they're all using such huge gearing systems; it certainly explains why they're all the size of a shoe-box! I'm curious if this is down to cost, stupidity or some technical issue with the linear actuators. It seems you could get the electronics, 2 or even 4 AAA batteries ( in the corners) and a linear actuator in far less space.</span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: Courier New,courier,monaco,monospace,sans-serif; background-color: transparent; font-style: normal;"><span><br></span></div><div><br><blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; margin-top: 5px; padding-left: 5px;"> <div style="font-family: Courier New,courier,monaco,monospace,sans-serif; font-size:
12pt;"> <div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"> <div dir="ltr"> <font face="Arial" size="2"> <hr size="1"> <b><span style="font-weight: bold;">From:</span></b> Stuart Poulton <stuart@poulton.org.uk><br> <b><span style="font-weight: bold;">To:</span></b> Closed list for developer discussions <opentrv-dev@lists.opentrv.org.uk> <br> <b><span style="font-weight: bold;">Sent:</span></b> Thursday, 21 March 2013, 7:59<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [OpenTRV-dev] The news !<br> </font> </div> <br><br>> The opto-reflective switches are for counting revs. They detect end-stop either by current (possibly easiest for detecting off-load) and/or load related changes in rotational speed.<br><br>Having seen the circuit diagrams, there is no measurement of motor current. It's the same mechanism as used in the HR20's from honeywell, which is to simply look for the motor to
stop turning.<br><br>In the case of the 'common mechanism' one of the drive gears has 3 silver disks on it, which match the location of the optp reflector.<br><br>Stuart<br><br><br>_______________________________________________<br>OpenTRV-dev mailing list<br><a ymailto="mailto:OpenTRV-dev@lists.opentrv.org.uk" href="mailto:OpenTRV-dev@lists.opentrv.org.uk">OpenTRV-dev@lists.opentrv.org.uk</a><br><a href="http://lists.opentrv.org.uk/listinfo/opentrv-dev" target="_blank">http://lists.opentrv.org.uk/listinfo/opentrv-dev</a><br><br><br> </div> </div> </blockquote></div> </div></body></html>