View Full Version : Vector graphics on cro

01-21-2008, 02:04 PM
This is a project that I did with a friend for a tafe course. It displays pictures on a CRO in x-y mode.

01-21-2008, 05:04 PM
Got to see your doing well with the Prop..
How did you get the signal onto the cro via composite video input on the CRO

Ron Nollet

01-21-2008, 05:11 PM
Nope, I have a proto board with some wire-wrap sockets on the output pins. I put the resistors into the appropiate pins and and wound the ends together. Then I just used CRO leads with alligator clips and clamped them onto the ends of the resistors. It was the probably the dodgiest setup you have ever seen but it worked like a dream.


01-21-2008, 07:23 PM
Nice Job.
Now if you wanted to be REALLY retro you could make pong. I'd love to see that on a oscilloscope.


- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
www.iElectronicDesigns.com (http://www.iElectronicDesigns.com)

Nick Mueller
01-21-2008, 08:21 PM
Take this one as a reference as how far you can get. http://forums.parallax.com/images/smilies/smile.gif


Nick, not wanting to make your job look bad!

Never use force, just go for a bigger hammer!

The DIY Digital-Readout for mills, lathes etc.:
YADRO (http://www.yadro.de)

Fred Hawkins
01-21-2008, 10:52 PM
Steven, how about a photo of the dodgiest setup ever?

01-22-2008, 10:43 AM
What's with the gaps (like the band of darkness through the eyes)? Any explanation?

Michael Park

PS, BTW, and FYI:
To search the forum, use search.parallax.com (http://search.parallax.com) (do not use the Search button).
Check out the Propeller Wiki: propeller.wikispaces.com/ (http://propeller.wikispaces.com/)

01-22-2008, 12:22 PM
I would assume the gaps are caused by low precision resistors in the DAC, right?
In which case using the 1K and 2K resistor ladder DAC method would probably help.
I disassembled a small TV to tinker with like VECTREX but didn't finish anything interesting on it yet.

01-22-2008, 04:35 PM
Unfourtantly I don't have a photo of it :-(

Nick, I like that clock. I'm glad I didn't have to design the board for the vector graphics generator. Its so much easier with a Prop.

The gaps are because the resistor values I was using at that stage were not exactly the right values. We just used the closest value that we had and then changed them if necessary (such as 1k2 instead of 1k). This got rid of the most visible gaps. I was going to make a text driver for it but I run out of time.

Bean, I thought about doing something like Pong but I run out of time and I don't have a cro to test it on at home. Otherwise I'd probably do it.