Bad Apple!! - Arduino + Led Matrix

My first try of displaying pictures on a 24x16 led matrix display by an Arduino.

Workflow : import and resize video (24x16 pixels), export black&white images of each frame, read each frame with PHP (for example) and write raw datas for the matrix, send raw datas via serial port to Arduino who read and display bytes. Music is played by my computer, not Arduino...


French people, join : http://www.facebook.com/pages/Arduino-France/104358999637098

Original source video : http://www.youtube.com/watch?v=G3C-VevI36s
One of the best stop motion I ever seen : http://www.youtube.com/watch?v=240Vq6tIxio

Song : Bad Apple!! / Artist : Masayoshi Minoshima / Vocals : Nomico

Category:

Film & Animation

Tags:

• bad
• apple
• arduino

[TheBypasser]

A matrix like this is very fast on the draw so you can easily implement a 256-level PWM. With it you can implement anti-aliasing, and the rest can be achieved by a matte acrylic cover, like 3mm that would make a nearly uniform lighting when all the leds are on. With all that it will give a perfect block-less image (blurred though). Not sure if Arduino will handle it all though, made something alike in AVRASM for a commercial scroller project.

[iBl0b]

@TheBypasser Hi. Thanks for you comment. 256 level PWM is perhaps too much. But I'll follow your idea to make a 4, 8 or 16 level PWM and see if it works. It could be nice. I think Arduino is able to handle that, but my limit is the speed of the serial link between computer and Arduino. I'll try with EEPROM or SD-Card storage. Perhaps it'll help. Thanks for watching and giving me useful advice !

[AKAtheA]

how about using a Teensy and it's brutal 13,5Mbit USB? ;-) you could stream it from the PC @ even greater resolution...

[iBl0b]

@AKAtheA I had to slow down the video to synchronise with the sound. At this 24x16 resolution, serial link is too fast... ;-)

[alphaman1101]

Tel me you didnt hard code all of that?!?! there is a serial interface right?

[iBl0b]

@alphaman1101 Yes, you're right. All the datas are on my computer and was sent to the Arduino live for display. The software on the Arduino is really simple : just get some data over serial port (via USB) and send them to the display.

Be careful : openning a serial communication from a computer to the Arduino over the USB bus will reset the Arduino. So, you have to open the serial port from the computer, wait for 2-3 seconds and then send data.

[MrEvanrich]

that's so nice of you that you posted the code you used....oh wait...

[chickenpoper]

What is the refresh rate? Also, did you use a little bit of PWM because it appears that some led's are brighter than others bot not even the brightness is constant.

[TheBypasser]

@iBl0blol yesterday was too sleepy - of course a discrete 256x PWM would not go as only leaves you 40 clocks to draw the 24 pixel scanline for 100Hz PWM @ 16 MHz clock. Also lookup table would never fit, I used 1kHz fullscreen dimming only. 8x PWM though is perfect for this use - allows true HD input (49x side). And port - 115200 = 12,5kB/s, a perfect 60fps (115200/9/16/24*2, two pixels per byte of course + framebuffer swap flag).

[majorearthlover]

>~O That seems time consuming.