Persistence of Vision (POV) Wands are a fun way to create interesting long exposure photographs and light displays. The wand consists of a single row of LEDs controlled by an Arduino Uno. When the wand is turned on it appears to be flickering in a random pattern, but if you move it quickly back and forth, you will see text or an image appear. This wand project is incredibly customizable, I've included all CAD files, firmware, build documentation, and schematics. Feel free to choose your own color LEDs, write personalized messages, and maybe even add something new to the project!
(1x) Arduino Uno REV 3 Radioshack #276-128
(20x) Amber Super-bright LED Indicator Radioshack #55050630
(1x) Arduino Proto Shield Radioshack #276-140
(1x) 9V Alkaline Battery Radioshack #23-866
(1x) Heavy-Duty 9V Snap Connectors Radioshack #270-324
(20x) 1/4 watt resistors (sample calculation below)
from the specs of the LEDs I used:
"Continuous forward current: 25mA"
"Forward voltage: 3V"
using the following relationship:
V(volts) = I(amps) * R(ohms)
R = V / I
we can calculate the resistance as follows:
voltage across resistor = 5V - 3V = 2V
2V / 0.025A = 80ohms
I used 100 ohm resistors
so that the LEDs wouldn't be operating at their maximum ratings. Check the datasheet of the LEDs you use to calculate these values.
I've attaching a fritzing
document with a breadboard and schematic view of the circuit (and included them above) for reference.