From: Isaac Marino Bavaresco <isaacbavaresco@gmail.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
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Date: Sat, 18 Jan 2020 14:39:51 -0800
Subject: RE: [CAUTION: Failed DKIM Test][EE] Magnetic lock
Thread-Topic: [CAUTION: Failed DKIM Test][EE] Magnetic lock
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It detects the change in reluctance when the magnetic circuit os closed.

I think it uses some magnetic sensor that requires more magnetic flux than =
can flow without the plate fully attached.

Cheers,
Isaac

Em January 18, 2020 10:07:34 PM UTC, Allen Mulvey <allen@amulvey.com> escre=
veu:
>Is there a small plunger connected to a microswitch which
>detects the physical contact?
>
>Allen
>PS: I use a pair of 600 pounders on my front door with
>magnetic strikes everywhere else.
>
>-----Original Message-----
>From: piclist-bounces@mit.edu
>[mailto:piclist-bounces@mit.edu] On Behalf Of David C Brown
>Sent: Saturday, January 18, 2020 4:27 PM
>To: Microcontroller discussion list - Public.
>Subject: [CAUTION: Failed DKIM Test][EE] Magnetic lock
>
>I have just purchased a magnetic lock for my workshop so
>that I can
>dispense with using metal tokens to free the door.
>
>The lock consists of an armature plate which bolts to the
>door and an
>electromagnet which, when energised, grabs the armature with
>a force of
>several hundred pounds.
>
>I splashed out an extra fiver for the "monitored" version
>which lights an
>LED anf operates a relay when the device detects that the
>armature is held
>by the magnet.  But how does it detect the locked condition?
>Does the
>current in the magnet increase when something is attracted
>by it?  Or what?
>__________________________________________
>David C Brown
>43 Bings Road
>Whaley Bridge
>High Peak                           Phone: 01663 733236
>Derbyshire                eMail: dcb.home@gmail.com
>SK23 7ND          web: www.bings-knowle.co.uk/dcb
><http://www.jb.man.ac.uk/~dcb>
>
>
>
>*Sent from my etch-a-sketch*
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