Detect if maglock plates occlude

I was very dismayed to find yesterday the temp change caused my magnetic lock armature plate to not seat properly, and a simple 4 lb pushed it open. Had to readjust custom made zl bracket.

Anyhooo... i soldered a wire to plate, planned to use continuity check. Problem is plate is almost always in contact... ie | or |/ .. therefore THAT idea is toast. so i figure i cpuld use leds and photodiodes across the plate. Id use pulsed signals to avoid ambient noise. If plates join, very little light is admitted thru..

Thoughts?

mattlogue: Thoughts?

A picture's worth a thousand words. posting images. You'll have to wait five minutes before editing.

To describe picture… the magnet and armature NEED to align perfectly. Any number of factors can affect this perfect “occlusion”. I want to know!

[D1] => LED -or- LASER ===> Mag/Arm Gap —> Sensor → [A1]

Or use a hall effect… but does the closure of plates, where hold is significantly better, affect the magnetic field in a way hall sensors can pick up?

mattlogue:
i figure i cpuld use leds and photodiodes across the plate. Id use pulsed signals to avoid ambient noise. If plates join, very little light is admitted thru..

See Diagram:
Opto_tube.png

The tube thru which the LED-photodiode 'see' each other could be any diameter to suit.

If you want the alignment accuracy to be, say, only 1mm then drill a 1mm hole on one side and 5mm hole on the other to fit the LED, same for the photodiode.

Yours,
TonyWilk

Opto_tube.png

Awesome. Thanks. I cant think outside of box. That would detect all mis occlusion. Even if tubes are parellel and spaced, ambient light would bias signal from photodiode.

If you use a phototransistor in circuit to an analog pin then you can detect when the signal is at peak.

Possible gotcha is dust/dirt getting in the tube. Optical fiber instead of open tube would avoid that but may also get dirty. Everything optical has the dirt issue but regular cleaning can keep that from being a problem.

If you put the led and detector in a V shaped arrangement so the led light reflects into the detector or not depending on the reflective surface being present then you can set one to reflect only when full-close.

You might be able to cap sense a closed door but IMO it could be subject to uncontrolled influences.

Just how exact must the alignment be? Is the end of the bolt tapered at all?

Stupid question maybe but have you confirmed your Mag Lock doesn't have Aux outputs? all of the Mags we supply/install have Bond Sense outputs using a Reed switch and Magnet set up.

You can mechanically force the position by driving a pointed bolt into a V notch just before driving the lock bolt. That's a machine thing.

For a little inspiration try watching Ralph Steiner mechanical principles on Youtube. It's a 1930 short film of ways that one kind of motion gets turned into another, all set to music. One DC motor can drive any of them. If you're thirsty, there's water.

The maglocks are funny. I can't use much mechanical allignment, not from the force of magnet as it is actually about an Alinco in terms of flux. The chunky armature just holds a lot.

I plan to cross-drill two 1' aluminum cubes. A Metal Supermarket is down street and awesome. I figure some dust will accumulate and i'm reading analog data, so it will follow a trend, unless it's a bug....

Anyhoo, my door flexes... that is a question way outside the scope of this forum alltogether. Flex is bad because you can just jimmy it open with a nice push and crowbar. I put my reed on bottom for this reason. No alarm yet, until I figure out my array error and splice into existing alarm amp.

Planning on moving it down to striker area... of course with trim to keep from smashing into someones thighs.