# Blue Bawls Automatic LED Light

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Ok get your mind out of the gutter. I am talking about the beautiful blue glass bottle that the Bawls soft drink comes in. I tried one the other day and thought the glass bottle could be used for something interesting. At first I was just going to stick an LED into it, but I wanted something a bit more interesting. So I threw together a quick and dirty circuit that uses a photo-cell to turn on a transistor which powers an LED. The parts should cost only 2 or 3 dollars, and are available almost anywhere.

Click here to see more PICTURES and a VIDEO of the Blue Bawls LED light
Here is a new schematic that allows for a On/Off/Auto switch

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## Step 1: Gather the Parts

Here are all of the parts that you need.

## Step 2: Breadboard the Circuit (if You Want to Test It)

Construct the circuit according to the schematic shown on the previous step.

Note: Depending on the photo-cell used the 100K resistor value might need to be changed. A pot could be used to determine the optimal resistor value.

## Step 3: Solder It Together

The cap is used to hold the light in position. All of the parts will be connected to the cap. Three holes will have to be drilled in the top of the cap. Then solder the parts together according to the schematic shown on the previous step.

## Step 4: Detailed Cap Construction - Prep. the Cap

There are two holes that are needed in the cap. One for the power and a second for the photo-cell. Since the photo-cell is large I simply drilled two holes side by side.

## Step 5: Detailed Cap Construction - Solder Method Step 1

Trim both resistors to the length shown (it doesn't matter what end of the resistors are used). Solder both resistors to the red battery snap wire (positive).

The resistor values are represented by color bars, look here for pictires:
[http://alan-parekh.vstore.ca/product_info.php/cPath/12_13/products_id/52" target="_blank" 100K ohms Resistor]
[http://alan-parekh.vstore.ca/product_info.php/cPath/12_13/products_id/40" target="_blank" 470 ohms Resistor]

## Step 6: Detailed Cap Construction - Solder Method Step 2

Solder the 470 ohm resistor to the anode of the LED (non flat side).

## Step 7: Detailed Cap Construction - Solder Method Step 3

Connect cathode of LED (flat side) to the collector (C) of the transistor.

## Step 8: Detailed Cap Construction - Solder Method Step 4

Install photo-cell.

## Step 9: Detailed Cap Construction - Solder Method Step 5

Solder the base of the transistor to the 100K ohm resistor and to the photo-cell.

## Step 10: Detailed Cap Construction - Solder Method Step 6

Make ground connection (Battery negative wire)

## Step 11: Detailed Cap Construction - Solder Method Step 7

Test it to see if it works.

## Step 12: Detailed Cap Construction - Solder Method Step 8

Protect the circuit using some hot glue.

## Step 13: Detailed Cap Construction - Solder Method Step 8

Stick the light on a bottle!

## Step 14: Non Solder Method to Follow

There are connectors that can be used if you don't want to solder the light together. Non solder construction details will be posted later.

Have a look at them here
http://alan-parekh.vstore.ca/product_info.php/cPath/10/products_id/46

## Step 15: Attach the Cap and Have FUN!

Screw the cap onto the bottle, connect the battery and turn the room lights off. The bottle should start to glow. Turn the room lights on and the bottle light should turn off.

Click here to see more PICTURES and a VIDEO of the Blue Bawls LED light
Here is a new schematic that allows for a On/Off/Auto switch

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## 184 Discussions

I have tryed to use a Lithium Battery(CR2025,3V) to replace the 9V "BIG BATTERY". And,the 470ohm should be drop out.i think that the Lithium Battery may hide under the cap.

12 replies

would it work using 2 LEDs

Hi James, could you post a schematic of this please? Here is a picture of mine.

probably 6months-1yr....iam guessin...dependin on the time ur room is dark...computer motherboards use the same lithium cells...nd they last for lik forever lol....

yea i made mine the same way...works grt...nd is pretty discrete since evrything fits inside the bottle....

I have tryed to use a Lithium Battery(CR2025,3V) to replace the 9V "BIG BATTERY". And,the 470ohm should be drop out....

of coz it depends on your photocell supply voltage and the LED working voltage range.

try using a trim pot to get the desired performance while still on the breadboard, then measure the trim pot's resistance with your ohm-meter. Then solder in that value resistor. No Muss - No Fuss

I did the same exact thing, but my LED is really dim. Any idea what could be wrong? I've progressed from it not working at all to the point there is dim light! :)