New Project – Glowing Recharging Table

September 8, 2011

My next project is a table that glows at night.

I plan to use a photoresistor and about 25 LEDs.

I will need to use a transistor and another power supply for the LEDs, along with the Arduino as the brain. I will connect them to the PWM pins on the Arduino to control how bright they are. 4 LEDs draw too much current for an Arduino pin, so I need the transistor and another power source.  Each Arduino can handle 40 mA of current and each LED has 20 mA of current.

In the photos here I was testing the transistor and LED setup.  I am using 2 2n222 transistors with 4 yellow 20 mA 2.0 V LED’s connected to each transistor. Each LED has a 100 ohm resistor connecting it to the voltage.

Here is some simple test code.  LED Test.

Update 9/26

Worked on the table over the last weekend.  Bought some legs from the Door Store and some Poplar planks from Home Depot.

One thing I did from the underside of the table top is drill some holes that don’t quite go through the board.  Then I stuck an LED in each one so you get some cool glowing spots on the table top.  If I had to do this over, I would probably do a design like a constellation or maybe the big dipper.  Since I was free handing this and don’t have a drill press, I was afraid of drilling through the top and didn’t want to do to many.

I also made a shelf to hide the electronics / power strip.

Now to finish wiring up the LEDs and other electronics.  This table will sit in my front hallway and serve as a phone / gadget recharging table that happens to glow at night.

Update 10/9

Soldered the brain together with the photoresistor and the LEDs.  I used a Prototino for the brains of this project.  It is basically an Arduino with extra space for soldering on componenets.  Also did some work on the table.  I am finishing it using Danish Oil and then Feed-N-Wax to protect the wood.


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