Alarm Essentials
www.kitronik.co.uk/2101
Checking Your Alarm PCB
Check the following before you insert the batteries:
Check the bottom of the board to ensure that:
All holes (except the 4 large 3mm holes) are filled with the lead of a component.
All these leads are soldered.
Pins next to each other are not soldered together.
Check the top of the board to ensure that:
The notch on the IC and the IC holder are in the same orientation as the markings on the Printed Circuit
Board.
All the resistors are in the right place.
The red / black wires on both the power connector and buzzer are the right way around.
The LED is in the right way around.
Both of the electrolytic capacitors have the ‘----’ marking on the PCB lined up with the ‘-’ on the capacitor.
Testing the PCB
When the batteries are connected, either or both the disarm LED / the alarm sounder may start.
To stop this, put the alarm into the disarmed state (push the slide switch so that it is at the end where the
wires are connected).
Now move the arm switch into the arm state (slide the switch the other way).
Close the door switch; the LED should remain off.
Open the switch and the LED should light, indicating that the alarm should be disarmed.
After around 20 – 25 seconds the alarm should sound.
If your circuit does not function as described, use the fault finding flow chart to resolve the issue.
Using the Alarm
To arm / disarm the system use the arm switch.
When exiting the alarmed area, move the arm switch to the arm position.
Close the door behind you.
Upon entering the alarmed area you have 20 –25 seconds in which to disarm the alarm.
The LED will light to indicate that the alarm needs to be disarmed.
Disarm it by moving the arm switch into the disarm position.
Should the alarm not be disarmed in the given time, the buzzer will sound (this will continue for 2 minutes or
until the alarm is disarmed).
