Weekend Project

I wanted to see if I could make a flashlight out of pennies. Since pennies after 1982 are mostly copper coated zinc they have the potential of making a battery. 

What you need:

Copper Side
Zinc Side
The first step is to sand down one side of the penny.  So that no one accuses you of defacing the money it is best to use the tails side, but ultimately does not matter. 

I did not have the patience to sand these down by hand.  I placed them close together on a strip of gorilla tape wrapped backwards around a board then used an electric sander.  Cuts through copper like butter!

The first time I did this project I used thick cardboard and the flashlights stayed lit for almost 2 days.  

I also did an experiment with fabric using an old cotton t-shirt.  Surprisingly this created more voltage by .3 v, but also lasted only about 6 hours in the end because it dried faster.  I would recommend leaning toward materials more like cardboard for longer power time. 

If you are using heavy cardboard I recommend soaking it in the acid for about 30 min prior to assembly. 

Stack the pennies all the same way (all copper side up and zinc side down, or vice versa, but not alternating) with the cardboard or cloth between each.  Attach an LED with the positive terminal on the zinc face and negative on the copper face. 

Wrap this contraption tightly with tape and you have a flashlight!

Using cloth I was able to tape the pennies together first then soak up lemon juice by dipping the finished contraption in the juice to activate it. 

If it does not light up.

  •  try reversing the terminals on your LED.
  •  make sure there the cardboard or cloth does not stick  out so far the touch each other and short the circuit.  
  •  check your LED to make sure it works
  •  check the connections
  •  use a different acid
  •  use different insulation material
The longest I have had one of these last is 2 days.  Most seem to last at least several hours and each cell seems to provide about 1.5 v and .30 milliamps. 

My highest voltage was 1.978 v

Not very successful experiment.

Above, I attempted to insulate a bolt with electrical tape and then space the pennies with washers and used cotton material.  It provided a sad 1.4 volts and only lasted 2 hrs.

Here are three different colors.  One made with vinegar, and two with lemon juice.  All were using thick cardboard soaked for 30 min.  

Vinegar was the small red light.  It lasted almost 2 days and only stopped cause it dried out. 

The green and yellow lasted about 24 hours. 

Where I spend a very comfortable third of my life.

In January I decided it was time to make a new bed.  I needed to get a new mattress and felt that the investment of a boxspring would be a waste of money and loss of potential storage space. So I decided to build my own platform bed.

I sketched out a quick drawing and went to work. I visited Home Depot and purchased $100 worth of lumber.

I did not follow a recipe and don't really have an accurate list of all materials.  I just went to Home Depot and walked around looking at stuff till it came to me.

If I did make a list of what I remember it would be...

  • A whole bundle of 1 x 3 slats 
  • 6 1X8 slats
  • 2 2x2 left over from another project
  • 3 4x4 redwood boards (they are very thick and light.)
  • 1 box wood screws 1 1/4"
  • 2 pieces of thin formaldehyde free plywood material
  • 4 fence post tops for the pillars
  • 16 carriage bolts (holds the 1x8s to the post and allows for quick disassembly when moving)
Basically the 1 x 8 are attached to the 4 x 4 with carriage bolts.   I also allowed for enough space underneath for plastic tub storage 18''.

Attached to the 1x8s are staggered 2x2 for the slats and plywood to lay flat against. 1x4 were used for the slats.

In order to give the shelves a more Zen appearance I changed my design to make the columns of the headboard go through the shelves at the last moment.

I purchased an LED strip from Amazon for $12 that i used to illuminate the underside of the bed.  Attached the fence post toppers, and stained with several coats of Polyshade to add a nice plastic shine and protect the wood.

For the plywood I wanted something durable, but not as heavy as construction plywood.  I found some formaldehyde free plywood that was lighter, and without the smell of formaldehyde.

Here is the finished bed.  I have been sleeping on it now for four months and it is still sturdy.  Since I live in an apartment right now I am very happy that it is so light.  If I had a house I would have used much heavier construction materials so it would last the test of time.

Update: One year later the bed is surprisingly stronger than I thought it would be considering the light materials.  When I moved apartments it was incredibly easy to break down, light to move, and quick to set back up. I simply folded the plywood pieces off, unscrewed the slats,  removed the carriage bolts.  I can store up to 8 large storage containers underneath.

LED Water Sound Light Show

Last weeks project was using my Arduino board, some C++ examples, and a strand of WS2801 addressable RGB LEDs.

This project was completed using mostly spare materials I had around the house.

Needed for project

  •  Drill with large drill bit (1/2 inch?  I used a 3/8 because i did not have a 1/2 inch bit)
  •  Plastic Tubing - (I used a shower rod cover made of thin plastic.)
  •  Electrical Tape
  •  3/8 inch clear tubing
  •  Water
  •  Arduino Uno or other chipboard/controller for ws2801 lights. 
  •  5V power supply
  •  1 strand (20) ws2801 LEDs
  •  Water pipe insulation (for appearance)
  •  Misc cutting tools.
  •  Sparkfun Spectrum Analyzer Shield or something else made with MSGEQ7 chip to analyze audio signals. 

Put LEDs in place.

Drill holes in your tube where you want your LEDs to be.  I placed one on each end of the tube, and down the length of the tube created holes opposite each other so the water looks as if it is flowing in a spiral.

Be very careful not to shatter your plastic when drilling.  Sometimes starting with small holes helps.  In this case I used a torch to smooth the holes where they were fractured. Heating the plastic also helped push LED's through where the hole was too tight.

The WS2801 lights fit tightly in 3/8 inch tubing.  It might be a good idea to seal them with silicon after filling them with water so they do not pop off and pour one ounce of water over your electronics.  The lights themselves are waterproof, but your Xbox sitting under your display is most likely not. I wrapped the tube with electrical tape over the connections between the light and clear tube


After I completed my initial spiral I was not impressed as it did not have even a remotely finished look.  I returned to Home Depot where I found some foam pipe insulation.  the color was a dark grey and I felt that would make the center pipe of the display blend better.

Finished Display

Here is a small video of the finished display.  The output from the TV audio runs to the spectrum analyzer shield and sends back 1 column of data, a number between 1 and 100 representing the strength of the signal.  The line in the code below that reads "if(Counter > 5){" causes the lights to move faster every time it encounters any signal higher than 5 otherwise it will slowly cycle through all the colors in silence.

 Arduino Code:
Here is the sketch I used, it is a modified version of the one by Adafruit that can be found HERE.

// Comment
#include "SPI.h"
#include "WS2801.h"

int spectrumReset=5;
int spectrumStrobe=4;
int spectrumAnalog=0;  //0 for left channel, 1 for right.

// Spectrum analyzer read values will be kept here.
int Spectrum[7];

//WS2801 strip = WS2801(32);

int dataPin = 11;
int clockPin = 13;

//WS2801 strip = WS2801(32, dataPin, clockPin);
WS2801 strip = WS2801(20, dataPin, clockPin);

void setup() {
  strip.show(); // all off

int pos = 0;

void loop() {
  // Some example procedures showing how to display to the pixels
  //colorWipe(Color(255, 0, 0), 10);
  //colorWipe(Color(0, 255, 0), 10);
  //colorWipe(Color(0, 0, 255), 10);
  unsigned int Counter, Counter2;  
  Counter = (Spectrum[0]/10); 
  //Counter = ((Spectrum[0] + Spectrum[1]+ Spectrum[2]+ Spectrum[3]+ Spectrum[4]+ Spectrum[5]+ Spectrum[6])/7)/10;
    if(pos > 256 * 1){ // 5 strips 25 colors 
      pos = 0;

   if(Counter > 5){ 
    pos += Counter;
    pos += 2;
    pos += 2;
  for (pos=0; pos < 256 * 5; pos++) {     // 5 cycles of all 25 colors in the wheel

void rainbow(uint8_t wait) {
  int i, j;
  for (j=0; j < 256; j++) {     // 3 cycles of all 256 colors in the wheel
    for (i=0; i < strip.numPixels(); i++) {
      strip.setPixelColor(i, Wheel( (i + j) % 255));
    strip.show();   // write all the pixels out

// Slightly different, this one makes the rainbow wheel equally distributed 
// along the chain
void rainbowCycle(uint8_t wait) {
  int i, j;
  for (j=0; j < 256 * 5; j++) {     // 5 cycles of all 25 colors in the wheel
    for (i=0; i < strip.numPixels(); i++) {
      // tricky math! we use each pixel as a fraction of the full 96-color wheel
      // (thats the i / strip.numPixels() part)
      // Then add in j which makes the colors go around per pixel
      // the % 96 is to make the wheel cycle around
      strip.setPixelColor(i, Wheel( ((i * 256 / strip.numPixels()) + j) % 256) );
    strip.show();   // write all the pixels out

void rainbowCycleOne(int j) {
  int i;
    for (i=0; i < strip.numPixels(); i++) {
      // tricky math! we use each pixel as a fraction of the full 96-color wheel
      // (thats the i / strip.numPixels() part)
      // Then add in j which makes the colors go around per pixel
      // the % 96 is to make the wheel cycle around
      strip.setPixelColor(i, Wheel( ((i * 256 / strip.numPixels()) + j) % 256) );
    strip.show();   // write all the pixels out

// fill the dots one after the other with said color
// good for testing purposes
void colorWipe(uint32_t c, uint8_t wait) {
  int i;
  for (i=0; i < strip.numPixels(); i++) {
      strip.setPixelColor(i, c);

/* Helper functions */

// Create a 24 bit color value from R,G,B
uint32_t Color(byte r, byte g, byte b)
  uint32_t c;
  c = r;
  c <<= 8;
  c |= g;
  c <<= 8;
  c |= b;
  return c;

//Input a value 0 to 255 to get a color value.
//The colours are a transition r - g -b - back to r
uint32_t Wheel(byte WheelPos)
  if (WheelPos < 85) {
   return Color(WheelPos * 3, 255 - WheelPos * 3, 0);
  } else if (WheelPos < 170) {
   WheelPos -= 85;
   return Color(255 - WheelPos * 3, 0, WheelPos * 3);
  } else {
   WheelPos -= 170; 
   return Color(0, WheelPos * 3, 255 - WheelPos * 3);

void readSpectrum()
  byte Band;
  for(Band=0;Band <7 data-blogger-escaped-analogread="" data-blogger-escaped-and="" data-blogger-escaped-band="" data-blogger-escaped-spectrum="" data-blogger-escaped-spectrumanalog="">>1; //Read twice and take the average by dividing by 2

void spectrum_init()
    //Setup pins to drive the spectrum analyzer. 
  pinMode(spectrumReset, OUTPUT);
  pinMode(spectrumStrobe, OUTPUT);

  //Init spectrum analyzer