Handheld POV Electronics Project
The PovardBy Ryan Winters
Jameco Product Manager
Description: The Povard
Assembly Time: 1 hour
Skill level: Intermediate
Parts and Tools List:
POV - Persistence of Vision Kit
2 AA Batteries
Povard. Now that's an interesting name. I figure it comes from a combination of POV, an acronym for Persistence of Vision, and Arduino because this message writer utilizes an Arduino to program messages and modes. The Povard is a large hand-held POV electronics project. It has a single column of LEDs, and if you were to just hold it while it's on, you would see the LEDs flashing in a seemingly random fashion. Wave the wand from right to left and it magically writes a word or message into the air. We've all seen comic flip-book animation where a scene is progressed one card at a time, but when done quickly, it appears as a scene in fluid motion. This POV plays the same trick on your eyes. The POV will display one slice of a letter at a time, and your brain combines the slices allowing you to see the message. Magic!
Building the PovardAssembling the POV is relatively simple if you've put together a solder kit before. All the components you need are included, even the snazzy laser cut and etched acrylic bezel. Complete building instructions can be found on the SpikenzieLabs website. There's also a great step-by-step video here.
Programming the PovardThere is a PIC microchip on the Povard, but you will use an Arduino and its IDE to program it. First, setup your computer and Arduino IDE to program the Povard. Download the Povard Loader v2 sketch. It is a zip file containing one file. When you open it, it will likely inform you that the file needs to be in its own folder and then create one for you. If you scroll through the sketch, you will see helpful comments and lots of options for the appearance of your message: spacing between letters, timing between phrase repeats, inverting the text/background colors, and whether the text will be displayed upside-down, mirrored, or normal.
Plug in the Povard to the analog pins of the Arduino with the pin marked SCL going into analog pin 5 and the unmarked pin goes into analog pin 0, as shown in the photo.
Attach the Arduino to your computer. Edit the message in the sketch. Hit the COMPLIE button, then UPLOAD. Do not touch the trigger on the Povard until the sketch has finished uploading.
The Arduino has a status light (Pin 13 LED) and when it is solidly lit, the loader sketch is running and ready to be programmed. The light will turn off for about 5 seconds while the Povard is being programmed, and when it is flashing, the Povard is loaded and ready.
Disconnect the Arduino from your computer, and remove the Povard from your Arduino.
Using the PovardHold the Povard by the end with the batteries in the palm of your hand. Wrap your fingers around to the front and use your thumb to push the little button that activates the message display. It would be a good idea to attach the lanyard strap and wrap it around your wrist to prevent accidentally letting go of the Povard.
Hold the button and the LEDs flash in what looks like a random pattern, but when you wave your hand through the air, you should see a message written in the air. The image below illustrates the technique Spikenzielabs recommends to make the message more legible. The movement does take some practice to get right, and you may also want to try adjusting some of the display values in the program to slow the message down or maybe speed it up.
Before swinging any objects, be sure the area around you is clear of people of obstructions. Always use the safety strap and use caution, especially in low light conditions.
What to do now? Well, this thing does have a leash on it, so I tried swinging it around in a circular motion. Now I can see the word "JAMECO" printed several times in the circle.
Viola! I might just rig this device into my bicycle spokes and share my greeting with the world!
TroubleshootingAt first, I had a hard time seeing my message, so I shortened it from "JAMECO ELECTRONICS" to just "JAMECO". I also adjusted the space between letters and the time between phrases.
Swinging the Povard by the lanyard and pushing the button can be a little tricky. I used a rubber band, wrapped around the handle to hold the button down.
Need more help? Check out the Povard web page.
Ryan Winters is a Product Manager at Jameco Electronics. His hobbies include working on cars and computers, fiddling with electronic gadgets, and learning robotics.