## Introduction: Dam It Light

In this instructable you will be making a vibration activated light. You can put the device on the table or floor. Hit the table or floor with a fist or leg and see the light turn on for the duration of vibration or remain on after the vibration disappears.

Click on this link to see the YouTube Video showing it in operation: http://www.youtube.com/watch?v=tYf8TaL1HE4

You will need:

- three bright LEDs,

- three 100 ohm resistors,

- matrix board,

- Two AA battery holder,

- Two AA batteries,

- soldering iron,

- solder,

- 20 cm of insulated wire,

- pliers,

- wire stripper,

- scissors,

- electronic packaging material,

- foil (make sure it is clean and not rusty - better you use new),

- hack saw,

- pen,

- preferably small heavy piece of metal,

- and blue tag (optional).

## Step 1: Make the Circuit

You solder the circuit as shown.

In the circuit shown each LED is modelled with three 1N4002 diodes connected in series because PSpice software does not have an LED component. The voltage across the LED is about 2 volts and the voltage across each diodes is about 0.7 volts. Three diodes connected in series would give a voltage of 2.1 volts which is almost 2 volts voltage across the LED. Thus three diodes can be used to model an LED.

I used a resistor for each of the three LEDs instead of using just one resistor for three LEDs. Although the voltage across each LED is supposed to be 2 volts it is never exactly 2 volts because of manufacturing tolerances. Some LEDs turn on at 1.9 volts while other turn on at 2.1 volts. Thus you should not connect LEDs in parallel because they all need a different voltages to turn fully on. If you connect three LEDs in parallel, some of those LEDs will be slightly dim and others will be fully on.

In my circuit I used one 120 ohm resistor because I only had two 100 ohm resistors not three that I needed. It would not make much difference on the operation of the LED. If you do not have 100 ohm resistors then you can also used 120 ohm resistors. Do not use any value less than 100 ohms because you might burn the LED or use more than 120 ohms because the light will be dim.

## Step 2: Cut Out Packaging

Use pen to draw around the circuit PCB and use hacksaw to cut out the packaging material.

The cube looking shape in the second photo will contain the LED circuit inside. This is why you have to cut it in the next two steps.

## Step 3: Cut the Bottom Piece

Use pen and hacksaw to cut out the bottom piece which would be a third of the total cube size.

## Step 4: Create Cavity

Use pliers to create cavity so that LEDs will fit inside the cube. You pull out pieces of the packaging materials with pliers.

## Step 5: Put Lid on Top of Cavity

Put lid on to cover the LEDs circuit.

Seal with masking tape.

Now the LEDs circuit is inside the cube.

## Step 6: Create Two Terminals

Use foil and masking tape to create two terminals.

Once those two terminals are connected the circuit will be complete and the LEDs will turn on.

## Step 7: Build the Walls

Use masking tape to build the walls to prevent the foil rock from falling on the table or floor.

## Step 8: Connect the Battery Holder

Use blue tag and masking tape to connect the battery holder. Blue tag is optional. You can just use the masking tape.

## Step 9: Make Foil Rock

Wrap a big piece of foil into a rock. Make sure you put the small foil square sheet on the bottom of the rock and wrap it around so that the bottom area is flat as shown in the second photo. This would improve conduction.

Instead of using the foil rock you can use a heave piece of metal. The problem with foil rock is that it might be too light and would not press hard on the contacts. I used a battery to add weight to the rock. However, that is a bad idea because the battery can add extra 1.5 volts to the circuit (via accidental contact) and burn all of the three LEDs.

You are now done.