Deadbolt indicator

Eric, this was going to be my question with any of these sensors. Hall or Reed - are they binary? If not, how do I dial in the LED to only t urn on at a certain point?

I'm very much into the idea of using a true switch vs a make shift one - wi th either I will learn a practical application. I just got into this who le hobby thru arduino - but when I went to solve my problem, i realized I d on't need to use that much tech - a simple circuit will do.

@John - I've looked at a few reed switches online, and it isn't immediatly clear to me how i might situate it within the jam.

Could I just run it vertically near the hole where the bolt goes? and if t he magnet is too strong or too weak, is there a way to adjust it?

Thanks to you all - these are some great suggestions and I'm learning a bun ch.!

perhaps Jim, If he wants to "MacGyver" everything. I would like to see him make use of readily available products but the who am I?

Tom

That was my thought.. well magnet and reed relay.

George H.

magnetic security switch is built for this AND looks decent.

The Hall effect device does not have to be a binary device but will act as a binary device if you buy one that is made to be a switch. You should look up the Hall Effect on Wikipedia to understand how it works and how it can be used in devices to do different things, making a compass for example. A reed switch on the other hand is a binary device and is called a reed switch not because it was invented by someone named Reed, but because the mechanical elements inside resemble the reeds used in a musical instrument. Like those in a harmonica. Because the moving parts in a reed switch have so little mass and are so close together the switch can be actuated rapidly. So with a magnet on a shaft one could be used to provide a signal to a tachometer. Eric

I have a tilt-switch gimmick on my garage doors that, by RF, talks to a display on my desk. ...Jim Thompson

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Jim, I'd be interested in knowing what parts you used for this. Garage doors are in the big picture too. Sounds cool. Once I tackle the actual cicuit I'll need to figure out how I want to get the message to someplace usefull in my house. :)

I don't think you need anything too fancy in the magnet department. Back in the early '70s when electronic fuel injection was just getting started, Cadillac (my employer) used two reed switches mounted on either side of the distributor shaft to pick up RPM and timing info. Dunno about the magnets, but I don't think they were anything special, even back then.

Best regards,

Bob Masta DAQARTA v7.40 Data AcQuisition And Real-Time Analysis

Scope, Spectrum, Spectrogram, Sound Level Meter Frequency Counter, Pitch Track, Pitch-to-MIDI FREE Signal Generator, DaqMusic generator Science with your sound card!

--- The recess in the jamb that the deadbolt goes into is about one inch in diameter and deep enough for the bolt to fit into without bottoming out.

What I'd do would be to measure how much room there was between the end of the deadbolt and the end of the recess, then see if the magnet and reed switch would fit between the end of the deadbolt and the end of the recess.

If there wasn't enough room, then I'd deepen the recess enough to get whatever clearance I needed.

Next, I'd stick - using its own force - a small magnet, something like this:

vertically, and centered vertically and horizontally, to the face of the deadbolt.

I'd prefer for the LED to be on when the deadbolt wasn't engaged, so I'd use something like this:

Wired like this: (View using a fixed-pitch font)

NC NO +-[R]-[LED>]-O->|

--- I don't understand.

---

--- Yes.

If you install the switch in the way I suggested, and the magnet is too strong, you can reduce its influence on the switch by rotating the magnet about its center until you get the sensitivity you want.

Once you find that point it'd be a good idea to immobilize the magnet

- with glue of some kind - so slamming the door wouldn't change its position.

If it's too weak, then the options break down to either getting a more sensitive switch or a stronger magnet.

---

--- :-)

-- JF

There are many types of microswitch - the ones I think are most commonly found, are the types usually used for the safety interlock on microwave oven doors. Some versions are the bare microswitch with the little "pip" on one side towards the end, this type usually has a recess on the same side as the pip, this is for an optional lever that can come in various lengths - such a lever might increase your options for making it work.

I was also thinking about adding a spring to the upper stripe in my diagram so that it could bounce back better...

Anyway, I have never done this kind of mod. :)

-- @~@ Remain silent. Nothing from soldiers and magicians is real! / v \ Simplicity is Beauty! May the Force and farces be with you! /( _ )\ (Fedora 19 i686) Linux 3.10.9-200.fc19.i686 ^ ^ 19:54:02 up 1:46 0 users load average: 0.00 0.01 0.05 ???! ???! ???! ???! ???! ???! ????? (CSSA):

BTW, don't turn that design into a IED (bomb)! :)

-- @~@ Remain silent. Nothing from soldiers and magicians is real! / v \ Simplicity is Beauty! May the Force and farces be with you! /( _ )\ (Fedora 19 i686) Linux 3.10.10-200.fc19.i686 ^ ^ 01:33:01 up 2 days 4:27 0 users load average: 0.00 0.01 0.05 ???! ???! ???! ???! ???! ???! ????? (CSSA):

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You can get a 'door alarm' at a Dollar Tree store for $1 that has a reed switch, a magnet in a plastic case and three LR44 batteries. It also has a small piezo sounder.

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have a DD214, and a honorable discharge.

But then he didn't get to make anything.

I get my magnets from KJ Magnetics. That same magnet is about 1/10th the cost from KJ:

Although, I didn't compare shipping rates.

Much less expensive? I just ordered 3000 hall effect sensors for $1.80. Tacked it on to another order I was doing. A reed switch might be easier for a beginner to work with, but the sensor itself isn't a huge cost.