Real time X,Y graph

msiriwardena

Hello all,

My project(working) has a Data Logger (Parallax inc. )The time and pressure is logged and I can load to EXEL and and plot
a X-Y graph.What I would like to do is to have a real time graph.
I woud like know whether is it possble and if so how to do this.If possible I would like detail instructions for hardware etc.

Thank you,

Siri

Mike Green

There's no automatic way of doing this. Another Propeller (like an Activity Board) could monitor the time and pressure and display an X-Y graph on a display (VGA or NTSC video) along with labels and axes. There's a graphics object in the Propeller Object Exchange that will work on either type of display. You'll have to write the program to format the graph. What's sitting between the time and pressure sensors and the Data Logger?

Tracy Allen

The old-school way to make a graph of a parameter vs time was to use a simple scrolling text window and a monospace font. Value =71...print 70 spaces and then a "*" and <CRLF>. Next value=70...print 69 spaces, ditto ditto etc.. It can get fancy with multiple parameters and auto scaling. Worked on tractor feed printers too!

What is the time scale of your process?

DigitalBob

I've used a good X-y in one of the basic stamp projects and I think the prop scope has one too.

Duane Degn

To go along with Tracy's suggestion to plot it out, Here's an example from my attempt to read my pulse.

You don't see the graph until 1:06 so skip ahead if the link doesn't take you to the correct location.

Edit: You have to skip ahead yourself. The link didn't work with the time index included. (Sorry about the clicking sound. I think it was the lens cap swinging and tapping the camera body.)

It was a pain to do this though. There's a PropBOE tutorial I based the graph on. I'll try to find a link to the original code.

Duane Degn

I found it.

http://learn.parallax.com/node/109

macrobeak

Viewport provides a simple graphing tool

Peter Jakacki

I did a real-time graph years ago with my Tacho.

msiriwardena

Mike,
The pressure sensor and Data logger are attached to a "Propeller Proto USB "board.

Thanks for trying to help me.

Siri

Mike Green

You've gotten a variety of suggestions. The Proto Board is already designed to add a VGA connector if that's the sort of display you want to use. You can also use a single I/O pin for NTSC text video output ... see the 1-pin keyboard and video driver in the Propeller Object Exchange. The comments show how to connect it. If you make the standard 3 resistor network, you can use the graphics driver for NTSC video. The graphics driver takes one cog and the video driver takes a second one. You probably have several to spare. ViewPort is a great solution if you're going to have an attached PC anyway.

Rayman

Here's a way to do a high resolution chart with Propeller VGA output:


http://forums.parallax.com/showthread.php?t=106118&highlight=strip+chart

Having trouble with this link... It acts weird under IE...

Rayman

I'll just repost that demo here since like to old post has some kind of issue...

msiriwardena

Thank you all for the suggestions.

Siri