Cylon Pumpkin




This has been done before. There are several good ways to do it: most use either a 555 timer chip and decimal counter chip, or an Arduino. Stefan and I used an Arduino (Boarduino, technically) which limited our scanner to 14 LEDs. No problem — 14 gives a nice scanning effect!

Cylon Pumpkin




Here’s how we wired it: the numbers on the Boarduino block refer to the digital lines d0–d13.

It’s only necessary to have one current-limiting resistor in the circuit, rather than one on each LED, since only one LED is on at a time and the LEDs prevent current from flowing back into the Boarduino on the “off” pins.
Now for the code. It’s relatively simple: just count up and down, turning on and off the count LED as you go.
// Cylon pumpkin driver
// Eric Ayars
// 10/24/09

#define MAXLIGHT 14

byte Wait = 50;        // Time each light is on, in ms
byte EndWait = 250;    // Time all lights are off at the ends

void setup() {
// Set all pins to output
for (byte j=0;j
pinMode(j,OUTPUT);
}
}

void loop() {

// Count up from 0 to 13, setting the light
// for each count.
for (byte j=0;j
digitalWrite(j,HIGH);
delay(Wait);
digitalWrite(j,LOW);
}

// Pause at the end
delay(EndWait);

// Count back down from 13 to 0, setting lights
// as it goes again.
for (int j=MAXLIGHT-1;j>=0;j--) {
digitalWrite(j,HIGH);
delay(Wait);
digitalWrite(j,LOW);
}

// Pause at the end
delay(EndWait);

}

Here’s Stefan with the completed “eye-bar”. We didn’t have a section of proto-board long enough to hold the entire scanner, so we split a long piece and spliced it together in the middle with short wires. This gave us the option of bending the unit in the center, which proved handy when mounting it in the pumpkin!

If you look closely, you can see that we used two 1k-ohm resistors in parallel instead of a 500-ohm resistor for the current-limiting resistance. Whatever comes in handy…
Cylon Pumpkin circuit

Rather than solder the eye-bar directly to the Boarduino pins, we soldered the wires to 8-pin female headers that then connected to the Boarduino. We labeled the headers to avoid confusion. 🙂 One side of the Boarduino has pins 0-7, and the other side has pins 8-13 and a connection to ground.

 

For more detail: Cylon Pumpkin




Clip to Evernote

Leave a Comment

(Spamcheck Enabled)

Read previous post:
blocks and devices
New service for you – comfortable labeling of cables, terminal blocks and devices

In line with broadening of our services and support to our products, we offer you a possibility to get off...

Close
Scroll to top