Introduction: How to Harvest a Piezo Element From a Window Alarm
In this short instructable I will demonstrate how I harvest Piezo elements from dollar store window alarms. Why you ask? Because these things are awesome pickups for guitars or any other acoustic instrument you are building. Also I am doing this to answer a question from a viewer of one of my instructables https://www.instructables.com/id/How-to-build-an-Electric-Guitar/.
Step 1: Take Things Apart
Open the battery compartment and remove the screw that holds everything together. Pull the back off. Pull the circuit board out and isolate the wires to the piezo.
Step 2: Isolate the Part You Want.
In the movies they would be sweating over which wire to cut first, no such issue here, cut them both at the same time.
Step 3: Remove the Part You Want.
OK, this is the only tricky bit, cutting the plastic housing to get the element out without bending it. A little bend won't hurt anything but you don't want to crack that white disc in the middle.

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9 Comments
6 years ago on Introduction
anyone knows how to make sound with this ? when I plug it to 4.5V no noise is made ?
8 years ago on Introduction
Dollar stores are your friend, cheap made stuff, with some good insides. Screws, wires, speakers, etc. You can even get solar panels and a rechargable battery from those yard lights. Thank you for this instructable, might come in handy in the future.
9 years ago on Introduction
Friger, you're still my hero. and by the way, i've started designing my electric uke. or (electruke). I can't wait to get to work on building it. :D
Reply 9 years ago on Introduction
I love the name, quick, patent it.
9 years ago on Introduction
this thing will make a noise when the magnet is removed but will turn off once the magnet is put back. you guys have an idea to prolong the sound for a few seconds even if you put back the magnet back? kinda like a delay?
9 years ago on Step 3
And the leftover can be used for lots of things. I have one for a fridge/freezer reminder. I soldered a LED where the piezo used to be and it blinks if either freezer door or refrigerator door is open
Reply 9 years ago on Introduction
I've never thought of that, great idea.
9 years ago on Introduction
normally they have a hal effect sensor too, unless they cheapskate
Reply 9 years ago on Introduction
im guessing the long folded metal pins overlapping each other are the reed switch, so cheap they didnt even bother with a real one O_o