Getting Somewhat More Serious 127Experiment 24: Intrusion Alarm Completed
Experiment 15: Intrusion Alarm Revisited
Time now to add some of the enhancements to the intrusion alarm that I dis-
cussed at the end of Experiment 11. I’m going to show you how the alarm
can be triggered if you install various detectors on windows and doors in your
home. I’ll also show how the alarm can be wired so that it locks itself on and
continues to make noise even after a door or window is reclosed.
This experiment will demonstrate the procedure for transferring a project from
a breadboard to a piece of perforated board that has copper connections laid
out identically to the ones inside the breadboard, as shown earlier in Figure
3-72. And you’ll mount the finished circuit in a project box with switches and
connectors on the front.
When all is said and done, you’ll be ready for wholesale circuit building. The
explanations in the rest of this book will get gradually briefer, and the pace
will increase.
You will need:
- 15-watt pencil-type soldering iron
- Thin solder (0.022 inches or similar)
- Wire strippers and cutters
- Perforated board etched with copper in a breadboard layout
- Small vise or clamp to hold your perforated board
- The same components that you used in Experiment 11, plus:
- 2N2222 NPN transistor. Quantity: 1.
- DPDT relay. Quantity: 1.
- SPDT toggle switch. Quantity: 1.
- 1N4001 diode. Quantity: 1.
- Red and green 5mm LEDs. Quantity: 1 each.
- Project box, 6 × 3 × 2 inches.
- Power jack, type N, and matching power socket, type N.
- Binding posts.
- Stranded 22-gauge wire, three different colors.
- Magnetic sensor switches, sufficient for your home.
- Alarm network wiring, sufficient for your home.