Pressure mat to Alarm clock

Discussion in 'The Projects Forum' started by philastine, May 22, 2009.

  1. philastine

    Thread Starter New Member

    May 22, 2009
    5
    0
    Hey guys,
    I'm currently working on a project which involves a pressure mat and alarm clock, the idea being that when an alarm sounds it wont turn off untill that person gets out of bed to stand on the mat. I want to attach this mat http://www.dse.com.au/cgi-bin/dse.storefront/4a16d94411d50a382740c0a87e01067c/Product/View/L5270- to the 'off' or 'snooze' function on an alarm clock (lets just say one that is battery powered - 1 AAA battery). There's probably a simple answer to this , but since my knowledge on the subject is very limited i figure i'd ask you guys for help.

    I attatched an image of the pressure sensor attatched to a buzzer powered by a 9 volt batery, a simple diagram i got off the website where i purchased it.

    Your help is greatly appreciated.
     
  2. CDRIVE

    Senior Member

    Jul 1, 2008
    2,223
    99
    Ya have kids that won't get their butts out of bed? :D
    If your alarm clock's snooze button is a momentary push button then all you need to do is get inside the clock and connect the pressure mat's leads across the snooze switch.
     
  3. philastine

    Thread Starter New Member

    May 22, 2009
    5
    0
    hey CDRIVE, thank you for your reply!
    The alarm clock i have contains a switch - [Snooze-On- Off], however there is a momentary push button 'light/alarm stop' which turns off the alarm while at the same time switching on a light to illuminate the LCD display.
    I took it apart, the photo of this is attatched.
    I believe the red wire on the far right connects to the light, the black one next to it is connected to the battery. The other three wires link to the main board behind the LCD display.
    Whereabouts would i make the connection between the pressure mats lead and this button wires?.
    Thank you so much for your help.
     
  4. CDRIVE

    Senior Member

    Jul 1, 2008
    2,223
    99
    Since the mat's switch is a momentary one you need to wire it across the contacts of the switch you described above. That should be the PCB pattern with an outer broken circle (like a horse shoe) and a center dot. The solder connection must be made to the traces that connect to those points and not the circles themselves, as it would screw up the switch contacts.
     
  5. philastine

    Thread Starter New Member

    May 22, 2009
    5
    0
    Since there are two leads running from the pressure mat (which would normally be connected to the battery snap and buzzer) are they both connected to the traces on the PCB pattern?
     
  6. CDRIVE

    Senior Member

    Jul 1, 2008
    2,223
    99
    Yes, you can either splice into the existing wires that connect to the switch pad or solder your mat wires to the board. Referring to your photo and starting from the right, the first orange wire is connected to the outer contact of the switch that looks like a horse shoe. The black and the next orange on the left of the black wire both appear to be connected to the center contact of the switch. Your two mat conductors should be connected to these points.
     
  7. philastine

    Thread Starter New Member

    May 22, 2009
    5
    0
    I tried splicing the leads, the alarm clock itself only worked when pressure was applied to the mat :confused:. I'll try soldering it, i will let you know how it goes.
    I appreciate your help:)
     
  8. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
    2,039
    287
    If this project does work you realize you'll become persona non grata in your own home. :D
     
  9. CDRIVE

    Senior Member

    Jul 1, 2008
    2,223
    99
    That's why I asked you earlier if the alarm clock employs a momentary switch to put it in snooze or disable the alarm. This is because the mat employs a momentary switch and will not latch anything. If the alarm clock can't satisfy this then we will have to build a latch circuit. Your photo does indicate a momentary switch contact, so I'm a bit confused about this.
     
  10. philastine

    Thread Starter New Member

    May 22, 2009
    5
    0
    Worked like a charm:D
    I just soldered next to the far right black and red wires, no problems at all
    Thanks for all your help, it is greatly appreciated!:D
    Cheers
     
  11. CDRIVE

    Senior Member

    Jul 1, 2008
    2,223
    99
    Have fun!:D
     
Loading...