Matt Reid
Electronics Design Specialist
1.0 PREAMBLE
In this project I turned my fan into a POV display(Persistance of vision). Although there is a lot of other projects on the internet doing something similar, I thought I'd give my own spin(pun intended) on it by using an actual fan rather than creating one from scratch. This uses a PIC16F88 to drive the LEDs and a wireless charging kit bought from ebay to power it. Programmed in Picbasic Pro and the images display are created in Matlab.
2.0 HOW IT WORKS
The way it works is there is a single strip of LEDs on one of the blade. There is an optical slot sensor on the back which resets the image every time the fanmakes one revolution which is how the image remains upright. To display an image, the program has the image stored in memory and has it separated into pixels. In this case the image is 78 pixels wide by 8 pixels in height. When the blade passes the optical slot sensor, the microcontroller loads one column from the image at a time on the 8 LEDs. Each time a column of pixels is appears on the LEDS, it is held for about 400 microseconds. The result is
2.0 The design
2.0 Power and Programming
I made an earlier version of this fan with only one color and using using batteries as the main power source. The main problem I found was that the batteries tended to run out fast and replacing them would constantly throw the balance off of the fan so you'd have lots of shaking. In this earlier version I also had to remove the entire main board to program the microcontroller, which also introduced balancing problems when it was it was re-programmed.
This time I powered it using a wireless cellphone charging kit I found on ebay for under 10 bucks. Using this I only have to balance the fan once and dont have any batteries to replace. I've also included a jack on the side to connect the pickit 3 programmer to upload a new image.
more info to come...