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Chameleon logoChameleon is a small video processing board meant for those who want to create realtime colored lighting effects based on TV images or other video devices. Unlike several software solutions already available, Chameleon will be a standalone device that does not require a PC for its operation. It will be able to handle either a Composite (CVBS) or S-video input and transform the video data into visual effects. It will have hardware PWM support for up to 12 channels, making it possible to show a different color on each side of the screen.

Latest news (2007-09-18)

Finally a proof of concept demo! For pictures and a video demo, see the software section.

Proof of concept demo (cyan colored)

2007-09-03

It has been a while since the last update but the project is still being worked on. Unfortunately my free time is limited so progress may be slow sometimes.

Currently I managed to get an 8x8 pixel grid from the video signal at 25fps and have the microcontroller read this. A small video demo is available in the software section. There is also some screen capture demos that were made some time ago but were never placed on the site yet.

While developping it became clear that the CPLD is a weak link in the system, having only a limited number of logic elements. I have decided to use an FPGA in the next version. The downside of this is and the reason I used a CPLD is that it requires more components (voltage regulator, program rom) and will probably make the board more expensive. However it allows for much better algorithms to be used.

My plan is to create a simple proof of concept with the first prototype and then focus on the second prototype, which hopefully will also be the final version. The following section shows some of the changes in the next prototype.

Prototype 2 changes

  • While the original idea was to create an open platform I have decided to keep things more closed in the next prototype. The reason for this is that there is a considerable amount of time and money spent on this project and I hope to get some of it back by selling the kits to hobbyists. Seeing many people commercially interested in the project as well I do not want someone to steal the project.
  • The CPLD will be changed to an FPGA (see above)
  • The open-drain outputs will not be as heavy (2A) as planned. Probably 500mA or so. Note that this is per single channel (red, green or blue), so this is more than enough and solves a lot of problems. 2A per channel would be 24A in total for all 12 channels! Nobody would probably need that. The power FETs will stay probably though.

News history

Date Description
2007-09-03 8x8 pixel camera demo, see software.
2007-06-17 Image sampling tests working, see software.
2007-06-10 Finished SVF parser and CPLD programmer. CPLD can be successfully programmed.
2007-06-08 SableCC grammar for the SVF format is written. Grammar compiles but further testing needs to be done yet.
2007-06-03 UART communication with handshaking finished. Basic JTAG communication with the CPLD works. Updated the software section.
2007-06-02 Prototype AVR programmer is working
2007-05-30 Worked on the Intel hex file parser.
2007-05-28 Started with the custom built programmer for the AVR. A simple blinking LED program works but the programmer is not finished yet. It can only write one page now.
2007-05-27 First tests with hardware. No smoke from the board :) AVR and USB seem to work fine, the rest cannot be tested yet.
2007-05-26 Prototype PCBs assembled
2007-05-23 Prototype PCBs arrived
2007-03-23 Prototype PCBs ordered

Specifications

  • Composite or S-Video input (but only one can be connected)
  • PAL format (720x576)
  • Stand alone hardware, does not require a PC
  • Power supply by unregulated 4.5V supply (around 300mA)
  • Protected against wrong power supply polarity
  • Up to 12 (4x3) high current (2A) open drain hardware PWM outputs
  • Completely programmable using USB, no need for AVR or CPLD programmers
  • Settings can be changed using PC software
  • Generic user I/O pins for extensions

Hardware

The three most important hardware parts will be:

  • Texas Instruments TVP5150: Video decoder
  • Altera MAX II EPM570: CPLD for video processing and PWM channels
  • Atmel ATmega324P: AVR microcontroller

See the hardware section for more detailed information about the hardware.

Planning

  • Design of first prototype
  • Order prototype PCBs
  • Build prototype
  • Write and test software, test hardware
  • Change design for final prototype
  • Order PCBs for final prototype
  • Build final prototype
  • Distribute final version

The bold item indicates the current state (as of 2007-09-03)


© 2008 MadWizard