Cheap Alarm

Discussion in 'General Electronics Chat' started by logicrules, May 8, 2010.

  1. logicrules

    Thread Starter Member

    May 3, 2009
    Hi, All About Circuits,
    I ran into a rather interesting situation; I purchased a bike alarm, and after some playing with the housing, it worked for about 9 mos., and the other day it quit.
    I know it was a cheap alarm but it worked good, daily. I had to go somewhere.
    I turned it off and went for a ride, and tried to set it when I got home; there was no sound.
    OK, the battery finally went, so I went to the store and bought a new one, 9V.
    I installed the battery, and went on to reset it, no sound. AHA, I thought, loose wire; so I opened it to find all intact. Now what? And here it gets interesting…
    When I purchased the alarm, and it arrived, I tried to install a 9V battery and it would not fit. ****! But do not despair. I have enough tools to make an attempt to make the battery fit. But… I informed the seller of the situation, and they said they will send me a new one with the guarantee they will test to make sure it will fit. Right! They did send a new one. The new one arrived, and I sucked up the loss and took to making the housing have the proper sizes. And it worked for 9 mos., or so.
    So I got out the replacement and tested it with the new battery (tested: 9.48v, cheap store, cheap battery.); it sounded but so low that it had to be placed near to my ear to hear.
    Of the various things that may reduce the sound on a device at this point sounds to me like a temperature problem I have in El Paso, TX.
    Now, I am asking for help in resolving this problem so I may learn more along with the rest of yooz.
  2. retched

    AAC Fanatic!

    Dec 5, 2009
    What is the brand and model of the alarm?

    Do you have a link to where you bought it?

    If the battery didn't fit, It may have been the wrong battery. It could have been designed for a different battery.

    Did it have the standard 9v battery connector on wires, or was it an integrated battery contact?
  3. logicrules

    Thread Starter Member

    May 3, 2009
    The alarm definitely, uses a 9V battery.
    There is a seam around the battery/Piezo area which can be lifted out with a small screwdriver. I used a high speed drill to remove almost all of the section separating the battery from the circuit. I then placed a plastic sheet cut from bubblepak in its place.
    While I was in there I also removed the ball bearing (which had separated from the Piezo wafer), and put a small dab of solder in its place.
    And so it has been functioning, up to now.