# A Simple Door Alarm

6,706

7

2

## Introduction: A Simple Door Alarm

In this Instructable I will teach those of you that don't know how to make a simpledoor alarm that's also cheap.

You will need:
about 2 inches of a wide cable with no wires in it
2 ringing alarms
1 piece of cardboard [about 1X4inches]
about 1.5 feet of wire [1/2 red, 1/2 black]
1 2.7 volt capacitor [this will boost the small battery]
1 1-volt lithium battery
1 regular size paperclip
2 tiny pieces of scrap metal [you can find in alleys]

Optional:
wire tape [very handy and keeps you safe from shocks]
plastic clip [handy if wires need to be pinched together to complete the circuit]

### Teacher Notes

Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.

## Step 1: Let's Get Started!

Start by twisting the wires on the two ringers.

## Step 2: Put on the Battery

Okay, tape on one of the open wires to the battery. To test if it works, put the wire to the other end of the battery. If it does a loud ringing sound, go to step 3, if not keep reading.
If no sound: check to see if the battery is dead or if the circuit is incomplete.
If faint buzz: flip the battery over to the - side or the + side.

[THE ORANGE CLIP IS THERE OVER THE BATTERY BECAUSE I HAD TROUBLE ATTACHING THE BATTERY TO THE WIRE. IT HELPED]

## Step 3: Attach the Super-Capacitor

Attach the other end of the battery to one side of the capacitor. The super-capacitor makes the small battery more powerful.

## Step 4: Make the Switch

Okay, now to make the switch... Start by punching two holes on each side of the piece of cardboard. Then fit the two reused metal scraps into the ends, and twist on the the paperclip to it.

## Step 5: Compete the Circuit

To complete the circuit, attach the other end of the super-capacitor to one of the metal scraps. Then attach the open wire[WIRE NOT CONNECTED ON BOTH SIDES] to the other metal scrap...

## Step 6: FINAL STEP

Attach all of this to a recycled back.
Then attach the wide cable right down the middle of it. Next, thread some thread down the cable and tie it to the end of the paperclip so that when you pull the other end it rings.
FINALLY... Attach alarm to a wall next to your door... Attach thread to door... Open Door...............

RIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIING!!!!!

## Step 7: Now...

do nothing.

Participated in the
Epilog Challenge

## Recommendations

78
100 28K
39
Large Motors Class

13,963 Enrolled