Why the V1 contact sensor is better!
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7 posts in this topic

You don't want to use any glue to hold the photo sensor in place if you drill the hole for it since you won't be able to open it to replace the battery. The leads provide enough stability to hold it in place pretty.

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It may be easier to hack but I am not sure it is better in all respects.

The V1 has a magnetic reed switch and the V2 is probably a hall affect
sensor which will react to the magnet but has no moving parts.

Reed switches are old technology (1940s IIRC) but that does not make them
obsolete. A reed switch can be actuated by a magnet or by a energized coil
which would make the assembly a miniature relay. But not very useful as the
current rating of most reed switches is very low.

If you want to experiment you might want to try actuating the reed switch using
a small coil which when energized will produce a magnetic field that will open
(or close) the reed switch. Reed switches are available in NO or NC configurations
so you can reverse the logic of a circuit (coil power goes on energizing the coil and
the NC reed switch will open breaking the circuit).

A hall affect sensor can also be actuated by a magnet but where the reed switch is a
open/closed condition a hall affect sensor is a transducer and can vary its output
proportional to the strength of the magnetic field it is subjected to. So it is possible to
do more than the simple on/off control of a reed switch.

Reed switches are also somewhat delicate and can be damaged if dropped or subjected
to a large shock.

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On 1/15/2017 at 3:51 AM, sparc said:

<....>

Reed switches are also somewhat delicate and can be damaged if dropped or subjected
to a large shock.

They can also be stuck/failed closed for devices that are in that state for a very long time, like a sensor on a window that rarely gets opened.

When I refreshed an alarm system at my house, a couple of recessed windows sensors based on reed contact switches were stuck closed for windows I hardly remember ever opening.  A couple of hard taps actually freed the reed switch and appeared to function normally afterwards, but I figured they just need to be replaced since you never know about their reliability and they're dirt cheap.

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I had a v2 contact sensor showing open last night so I checked the door it was on and the door was closed so I opened it and closed it again and it updated to closed in the app.  Not sure if it was the contact sensor that screwed up though as my hub was rebooting itself many times yesterday for no apparent reason and that may have made it miss the closed notice.

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19 hours ago, Terk said:

I had a v2 contact sensor showing open last night so I checked the door it was on and the door was closed so I opened it and closed it again and it updated to closed in the app.  Not sure if it was the contact sensor that screwed up though as my hub was rebooting itself many times yesterday for no apparent reason and that may have made it miss the closed notice.

My front door is  V2 sensor and I have actually had this happen several times with that particular sensor.

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