United security pressure mat

https://www.vesternet.com/knowledgebase/technical/kb-85/

Necromancing this thread just to say thanks to everyone. This is one of the coolest things to me, and was a good showcase of the flexibility of both the tech and the community. It’s working fantastically as a “bed presence” sensor to help run my Goodnight routine (it was previously managed with just motion sensors, which are ineffective if I’m idly at the computer).

I bought the inexpensive Ideal Security mat from on Amazon listed earlier and on the Instructables link. Instead of stripping the wires, I bought a matching pigtail to connect the mat to the dry contacts, just for ease of use. I have 20 19 of them, so if you have (or buy) this model, I’ll give you one if you don’t mind covering the cost of envelope and stamp.

Also, as of this writing, that mat is super-cheap through Amazon Warehouse ($16 - $20 with an additional 20% off for a limited time), if you don’t mind cosmetic issues for a product we are covering up…

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Thanks for writing. I have had my two pressure pads working flawlessly for 4 years in my kitchen and in my wet bar. It is like magic. So much so that when I am in another house and I step up to the sink and the light doesn’t come on, I get confused and then annoyed! LOL. I haven’t tried one as a bed sensor but I might just add that next. I am having issues adding new zWave sensors since I think I am at the limit for the hub. Anyone know how many devices one can have?

EDIT - found answer… 232

So I have to find a workaround soon. At about 180 today

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Has anyone found a small pressure sensor (the size of a deck of cards) that I could use instead of the large pressure mat? I’m looking for something I can just connect to the ecolink ON/OFF sensor.

These exist, you can usually find them at robotics supply companies. There’s some discussion of them in the smart chair project thread. (The topic title is a clickable link.)

@JDRoberts These exist, you can usually find them at robotics supply companies. There’s some discussion of them in the smart chair project thread. (The topic title is a clickable link.)

I noticed there is a LittleBits pressure sensor mentioned in this thread that’s as small as a deck of cards . I didnt see any other specific pressure sensors mentioned in this forum thread (or the other link you posted) that’s relatively small. I already own an Echolink ON/OFF door sensor with two terminals inside (See below picture).

Could you or someone else here please tell me how to connect the LittleBits pressure sensor (or something else comparable) to the Echolink without soldering or buying extra parts or wires? The Littlebit doesn’t look like it has two wires coming out of it like the pressure mat with alarm mentioned in this thread.

See the second link (the one for dummies) in post 20 of the thread I already linked for you:

Smart Chair

Also post 21 in that thread is relevant.

But, seriously, you can make one yourself out of a couple of pieces of cardboard and aluminum foil. And some bits of wire, I don’t know what to tell you if you don’t want to use any wires.

Literally all you’re doing is creating something where most of the time there’s a little bit of air in between the contact plates and then putting pressure on the pad closes the circuit.

See the following video. I made one something like this in third grade to go with a potato battery. :wink:

image

The fancier ones you can buy of velostat or what looks like fabric are the same principle, they’re just using a gel type interior that can compress. You should be able to find them for under $15, maybe less. Any place that sells to arduino or robotics hobbyists should carry several styles and sizes. I know Adafruit has some.

@ogiewon

I bought these from Amazon. Work great.

FORCE SENSING RESISTOR,1.5 INCH SQUARE,1oz-22LBS,2 LEADS,0.1 INCH SPACING https://www.amazon.com/dp/B00B887DBC/ref=cm_sw_r_cp_api_i_ybj6Eb303CZHV

EDIT - never mind, I see you don’t want to do any soldering. Hang out here long enough and that aversion will fade. The new skill of soldering wires will open your smart home world to many more new opportunities.

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So an update … two things. First, the soldering of the wires to the end terminals is very delicate and has to be done carefully. I botched it on my second sensor but eventually got it back by melting through the flat wire coating further up the terminal, but it wasn’t pretty.

Second, these sensors are very sensitive and close the circuit with very slight pressure. They do read out variable resistance but that doesn’t help you when using to just short two terminals. I would be interested if anyone knows of a way to ignore the short below a certain resistance. I can’t think of an easy way but then again I suppose one could borrow voltage from the contact sensor battery to do something clever with a cutoff circuit. I will work on that but thought I would ask first to see if anyone has done that. Without this hack these sensors have a hard time bouncing back to open after one sits or steps on them.

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