Thursday, November 09, 2006

 

Hamamatsu wired in and running...

This is a little tiny step. I was able to determine that the Hamamatsu limits detector was working fine with not a lot of trouble. Once I tried to get the motor control programme to detect the signal, however, all sorts of weird and wonderful things happened.

I finally tracked the problem down to the WAITMS (wait millisecond) command in the BASIC compiler. It wasn't written with the notion in being used in really event dense environments. I slowed the pseudostepping down and the code worked fine. You can see the GM8 changing direction when the Hamamatsu chip is brought near an IR opaque surface here.

Here you can see the limits sensor bouncing back and forth between two strips of white electrical tape put down on the work surface.


Oddly enough, when I duct taped the sensor boom to Tommelise's frame rather than using the big iron c-clamp the whole thing started working perfectly. I wonder that all that is about? I've had the positioning stage playing ping pong with the two tape limits for about an hour now with no problems whatsoever.

All this means is that I'm going to have to overtly programme timer2 to do the wait states instead of using the WAITMS command. It's annoying, but no big deal.

BTW, the Hamamatsu chip seems happiest about 3-4 mm above the work surface.

Comments:
***Oddly enough, when I duct taped the sensor boom to Tommelise's frame rather than using the big iron c-clamp the whole thing started working perfectly.***

Have you got all your resistors and 5v feeds setup right? I noticed, before i placed the R5 resistor between the 5v and the max limitor's control line, that just electromagnetic fields themsleves were sometimes enough to trip the limitor... At one point, without it actually being hooked up to anything, me touching the insulated 5v wire (that was supposed to run the IR sensor) with my finger caused enough interference to trip the 'sensor' (the next pin over)... The strange behavior was only on the max limitor, and it dissappeared once I put R5 on the board...
 
I've got everything rigged as the normative schematic said. I triple checked that.It's interesting to hear that I'm not alone in noticing that kind of behaviouir, though.
 
Post a Comment

Links to this post:

Create a Link



<< Home

This page is powered by Blogger. Isn't yours?

Subscribe to
Posts [Atom]