This page last updated 01/21/2001

My Video Digitizer Project

[The quick story]

I saw a web page explaining a method for implementing a range finder using a laser and a TV camera.

I needed a video digitizer that would interface to a microcontroller so I dug my ImageWise digitizer out of a junk box.

This is the original Circuit Cellar ImageWise Transmitter that I started with. I disassembled the code and made it grab two half size images. This allowed me to get an image from the odd field and even field. I then wrote code to subtract the two fields which left me with the image of the laser beam. Then it scanned the video line to return the location of the max pixel intensity. So I ended up with 128 values. Each value represents a range.

I wanted a version which was not copyrighted and was not processor dependent. So I breadboarded this version using TTL logic. (Note: there is an 8751 CPU on the board.)

Once I got the breadboard working I laid out a PCB. This board is interfaced to a CPU of choice. (Note: This is a "kitchen sink" board.)

I thought I had way to many parts. I also wanted to try out my Xilinx starter package. So I created a CPLD which replaces all the logic chips. The XC9536 CPLD replaced 10 TTL logic chips. (Note: This version had a 68HC11 daughter board. Which isn't present in the photo.)

The next step will be to lay out a PCB for the CPLD version of the digitizer.

Update 1/21/2001 - I have started the schematic and board layout.

Preliminary schematic. Click on schematic for a REAL big image.

Preliminary layout. I still need to add the laser driver.

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