How to make a Propeller Display

Things U Need

1. 8 LEDs
2. 8-10 meter long wire
3. 11 Male Burg-Stick pins
4. A small dot-PCB (optional)
5. A wire-cutter (optional)
6. Soldering Iron & Solder Wire
7. AVR kit (Brics Students already have it) or a microcontroller+programmer+breadboard

Time Required

1-2 hours maximum.

Difficulty Level

Between easy-average.

Actually after reading this it'll be very easy to make your own propeller clock.

Step 1:

Take 8 leds and short the negative terminal of each led. If you want to make it easy then first insert every led in  a dot-PCB (first cut the PCB as shown in image). Make sure all leds are in same format (either +ve terminal upward or vice-versa). Now you can easily bend the -ve terminals of all leds  and solder them.

Step 2:

Cut the +ve terminals as shown in image, leave only 2mm approx. of terminal.

Step 3:

Take 8 wires each of 1 meter and solder each wire to each led's +ve terminal, and lastly tie the end with some wire so that the wires don't fly out when you are rotating them.

Step 4:

Take 11 male burg-stick pins, solder the 1st led's wire (starting from bottom) to 1st burg-stick pin, 2nd wire to 4th pin (yes leave 2 pins empty [only for BRiCS kit]) likewise other wires to remaining pins. Other Students can directly insert wires into breadboard (See the pins of ATMEGA-16, ATMEGA-8 first).

Step 5:

Now students having kit insert the pins into any port, others dont need to do anything else if you have already connected your MCU on breadboard to wires.

Construction part is over, isn't that was fast!

Now only programming part is left over

If you know the concept behind the working of propeller clock then skip to Step-6, else read this.

When the array of led is moving fast in circle then the leds which are blinking very fast gives a impression that some message is being printed because of Persistence of Vision (POV). 

Lets assume on time 't' the array is at 90 degree in air, all leds are glowing, after a milli sec later when the array displays a little in clockwise direction then lets say from top 4th led is glowing, similarly for 3 more times 4th led is glowing and 4th time again all led glows.
Can you guess what will happen?
You will see that letter 'H' being printed in air.

Step 6:

Produce the "decimal numbers" of the required message that you wish to print in air, by using excel if you dont know how to do it dont worry read this post "How To Use Excel To Generate Code For Propeller Clock & LED Display".

lets assume you wished to display a heart, the decimal code for heart is 6,15,31,62,124,62,31,15,6,0. You can guess how this works by seeing the image below or else read the above post "How to Use Excel..........".

The code will be:

char a[]={6, 15, 31, 62, 124, 62, 31, 15, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, i=0; 

// extra zeros so that two hearts dont overlap

for(i=0;i<=20;i++){

  PORTB=a[i]; _delay_ms(5); // if it flickers then use _delay_us(500) or even low.

}

To get complete .c file click download.

Please Share it! :)

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