Quote:
Originally posted by Jeff McCune
We originally looked at the CSMP03, which runs about $40 and has a 20ms response time and is accurate to within a few degrees. Unfortunately, we couldn't buy it from a dealer authorized by First, so we had to build our own.
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Cool! <searches> Hmmm... No hits... Who makes it?
Quote:
Originally posted by Jeff McCune
I forget which part number we ended up buying, but basically it's a $20 2-axis magnetic sensor from digikey. We've got an ECE guy who wired up a nice circuit with some op-amps to condition the output from the senor (I'm CIS, so that stuff is beyond me a bit.). It outputs (...) The compass sensor + support circuit only ran about $40. The stamp-2P we bought is the most expensive part, just under $100.
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Wow... That's nice! Boy, I wish I had a spare EE for some custom analog work! I'm an ECE myself, but I was sick for two weeks and now I'm coordinating about a hundred
other things. We also lost a couple of people due to work/home situations. Our one college ECE student mentor who I was HOPING would take on the custom chip stuff has taken over teaching PBASIC to the students and monitoring software progress when we lost our original software mentor. (Thank goodness HE is still on board!) We figure that having a robot MOVE was a
slightly higher priority than having REALLY wild electronics...
We'll be at the Buckeye, so you'll have to give me a tour of your system then.
OUR original plan was going the opposite route, the "workstation" vs "mainframe" philosophy. LOTS of $5 PICs each screaming along doing something trivial in short C code snatches, instead of blowing the budget trying to Kitchen Sink something in one (relatively much slower and more expensive) Interpretive Basic chip. We can throw
10 PICs at something for the price of
one Stamp! By keeping the code short and one-tasked in each, we thought we could crank out a few PIC projects in time.
Unfortunately I'm swamped, and the PIC gurus I know with burners are all busy, so now we're back to kitchen sinking it too in HLL just to "get it out the door". :sigh: Should be cool though, IF we can pull it off. A few unusual items (which I'll outline later...) For now though, we're already stripping our "Big Plan" down to just the basics, and dropping to Plan B for the rest. Our original autonomous concept went with the PICs, so now we're doing something different.
(Of course... if there's a bored PIC Guru in the Ann Arbor MI area monitoring that wants to get involved in this contest, CALL ME TODAY!

)
Quote:
Originally posted by Jeff McCune
The 2P has 32 general purpose I/O pins, so we just set 16 to output and wired those directly to rc_sw_A and rc_sw_B. We've then got 16 lines still available on the 2P for any sensors we need.
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Are you getting bytes through reliably via parallel? I'm hearing a lot of horror stories about how since the I/O PIC and the RC are asynchronous, some people are getting funny values every so often because one nybble may be old data, and another the new one.
Quote:
Originally posted by Jeff McCune
This faster cycle time allows us to do interesting stuff like implement soft interrupts on some of the extra I/O pins. (This is how we're doing our shaft encoders.)
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Hmmm... Maybe we'd better look into a 2P as well... Back to the spec sheets! Good luck to you!
- Keith