I’ve been inspired by spokepov LED display from ladyada.
The term POV means persistence of vision. The hardware and software used by ladyada is opened to all. Everyone can download those files, make it according to their instructions and burn it with the firmwares. It is like DIY – Do It Yourself.
But I have some limitations. My bike is only 11-12 kg and I don’t want to make it heavier. They used several(6) 74HC595 in their schematic. It will add extra weight, add more costs, drain battery power, make the schematic more complex….etc ..
Yeah, their project is one of the best open-source POV projects i’ve seen in the internet.
And they have used some kind of attiny chip(maybe ATTINY2313) to their project. This is a great problem for me cause I want to use atmega8 in my project and I have several atmega8 laid in my home.
As we can see, when we use atmega8 as a arduino, it has 19 I/0 pins. This is a bright idea for me cause I can drive 19 LED direct and without any port expander/serial to parallel converter.
Then I wrote a simple program, flashed a atmega8, make a circuit on a piece of veroboard, and put it on my bike’s front wheel with the help of hot glue/silicon. And after some bug finding, the finished project looks like this.
The bike is running
The bike is running again
I’ve pulled up the handlebar and rotaoe the front wheel. A long exposure looks like this image.
A better image, more rpm of the wheel and far more long exposure……..
I am not fully satisfied with the results but this is enough for me now. I will update it later.