Sep 2, 2011
If you are looking for some fun with your Computer and have an amateur interest in Electronics then the Arduino is the ultimate companion. The Arduino is cheap, easy to use, easy to program and the possibilities are endless.
This is my first Arduino POV project. POV – Persistence of vision is the phenomenon of the eye by which an afterimage is thought to persist for approximately one twenty-fifth of a second on the retina.
Put simply; it’s a programmable sign. You can have it display any message or picture you set. We are basically flashing the 5 LED lights in sequence while a motor turns the lights around. Because the arm is moving at speed you are seeing the lights 20 times per a second in differing sequences tricking the eye into seeing it as a banner.
Aim of the Project
Put simply, its a programmable sign. You can have it display any message or picture you set. We are basically flashing the 5 LED lights in sequence while a motor turns the lights around. Because the arm is moving at speed you are seeing the lights 20 times per a second in differing sequences tricking the eye into seeing it as a banner.
1 x Arduino Compatible Processor (I used a KitTen from freetronics only $26.95 AUD http://www.freetronics.com/products/kitten)
5 x SMD LEDs or 5 x LED
5 x 1K Resistor
1 x 8 pin 90-degree locking header
1 x 40 pin terminal strip
1 x 9v Battery Clip
1 x 2.1mm dc power line female connector
Connecting Wire (I used an old IDE Cable)
2 x Small PCB Board
1 x Ruler or suitable board for arm
1 x Small DC Motor (used Tape Player motor)
1 x 9v Battery
1 x dead 9v Battery for counterweight
Suitable Base (old CDROM)
Hot Glue Gun (my best friend)
Technical Background Required
Some basic understanding of electronics and Programming can be handy but not necessary.
Take an old IDE cable and split off 6 wires.
Mount your LED’s on one of the small PCB boards. If you use SMD tape then you can simply cut the strip up and stick them on the board.
Solder a piece of cable across the negative side of all the LED’s and then the other connecting leads for the positive sides of the LEDs.
Solder the other end of the cable to the 90 degree locking header.
Now take the other PCB board and solder the 90 degree header on one end of the PCB and the terminal strip to the other end of the PCB board.
Solder the Terminal Strip to the other side and other end of the board.
Solder the individual resistors.
Solder your 9V battery clip to the DC power line connector.
The Base and Arm
Hot Glue a suitable DC motor to the CDROM unit (or any suitable heavy base).
Hot glue your battery, Arduino board and LED’s to your ruler/arm.
Hot Glue the arm to your DC Motor.
You may need to counterweight one side of the ruler/arm to prevent vibration; an old 9v battery is suitable. To check you have counterweighted the arm correctly turn the project on its side and the arm should balance out parallel to base. If one side falls then you need to adjust your counterweight.
Connect your LEDs to your Arduino using your newly created LED interface board, Plug the interface board in so that the terminal strip connects from pin 2 on the interface board.
Use the LED_Test code to test that the LED’s are firing correctly. LED_Test.pde
The LED_Test program simply cycles through each inpidual LED so that you can check that everything is working correctly.
Displaying a Message
If the above test has been successful then you are ready to display your first message.
Try loading the POV_Banners.pde sketch into your Arduino.
I made use of the character generator by DanielJA (nice simple concept)
Improvements to be made…
The addition of a hall sensor would allow me to steady the text and control the scrolling and prevent it scrolling backwards but unfortunately that is going to have to wait for another rainy weekend.