Which location for asking questions about the Prop Backpack
Buck Rogers
Posts: 2,190
Hello!
I am considering adding a Prop Backpack to my collection, yes its this guy: http://www.parallax.com/StoreSearchResults/tabid/768/txtSearch/backpack/List/0/SortField/4/ProductID/602/Default.aspx . Reason being is that's something of a middle of the road device, it has a Propeller processor and it speaks to the Basic Stamp. And as such I am wondering which Forum location to ask any questions about it.
Obviously Propeller questions have their own queue, and the ones for the Basic Stamp would land inside its own.... But that's the predicament. Can the thing be considered separately or together?
For example I bought the Prototype board for the Propeller back in September, intending to apply its talents to both video graphics creation and the regular abilities of the device to talk to the many things I build, but I'm still working on that idea. Now with this gizmo I'm now convinced its doable, but from the perspective of the Basic Stamp.
And examining the documentation for it, I see endless possibilities.
And given the daughterboard connector on it, I see even more.
Now who at Parallax came up with this good idea? A reward is in order.
I am considering adding a Prop Backpack to my collection, yes its this guy: http://www.parallax.com/StoreSearchResults/tabid/768/txtSearch/backpack/List/0/SortField/4/ProductID/602/Default.aspx . Reason being is that's something of a middle of the road device, it has a Propeller processor and it speaks to the Basic Stamp. And as such I am wondering which Forum location to ask any questions about it.
Obviously Propeller questions have their own queue, and the ones for the Basic Stamp would land inside its own.... But that's the predicament. Can the thing be considered separately or together?
For example I bought the Prototype board for the Propeller back in September, intending to apply its talents to both video graphics creation and the regular abilities of the device to talk to the many things I build, but I'm still working on that idea. Now with this gizmo I'm now convinced its doable, but from the perspective of the Basic Stamp.
And examining the documentation for it, I see endless possibilities.
And given the daughterboard connector on it, I see even more.
Now who at Parallax came up with this good idea? A reward is in order.
Comments
The Propeller Forum is as good a place as any for your Backpack questions. I know a little bit about that board, so I'll be glad to help as best I can.
-Phil
No one knows who developed the Backback. It just appeared in Parallax's front lobby one day, with an address label was that badly typed with a lot of typos. Inside was the documentation, schematic, sample board, and tons of black and white cat hair.
-- Gordon
BTW Count me among the fans of the backpack.
And the little pieces of shrimp shell was a dead giveaway.
Hello!
Okay. That one was a hoot. I'm getting one. (Same here,)
Now what caused the shrimp shell and of course the black and white cat hair? Oh and a badly typed address label, and of course the typos......? I happen to be a supporter of cats everywhere, the bigger the better. Also penguins. There are more of them working then on the South Pole gawking at tourists and scientists.
But seriously, I explained the whole business to my brother, and described the processor also approximately how I explained the Prop prototype board to him earlier, He was rather surprised with the idea that the Prop is quite popular with the retro gaming movement. And was also surprised with the ideas on how to communicate with the backpack. I also explained my reasons behind the device, that it would be perfect for displaying on a video screen the digital data that my logic puzzles produce, also via the basic stamp.
Hello!
A follow up, plans are still going on to buy currently one of these. I am also considering adding some of the other suggested items that are also shown on the page for the backpack. It might also include the selected prop plug.
Again many Thanks Phil
Hello!
Now the funny part. Can the backpack support a touch screen? I'm looking at two, via the collection at Sparkfun, one is a replacement for the one worn by the NDS, and the second one goes for replacing the one on the PSP. I originally thought of the BS2 doing it directly via the RCTIME instruction, But since the average TS supports two coordinates, an X one and a Y one, it'd require the instruction to keep track of two resistances. Strangely enough the Ard****o can do it, people have done it, for a different display and device, and then for the Nokia knock off.
I think the Prop can do it, but, ah, I'm not sure. And the reason why I'm continuing it here, is because of the extreme off topic nature of the entire thread. Like how can the firmware be customized on it......?
-Phil
Sheesh. What he should say is that he designed it and wrote tons of code to do all kinds of interesting things with video and communication. You've got the experts on your problem, Buck!
Ken Gracey
It's such a good idea that Parallax couldn't have thought of it, so we outsourced our innovation to Phil Pilgrim. He doesn't seem to subscribe to the corporate environment - complete with meetings, human resources departments and committee decisions - so he's stayed happily somewhere in the northwest instead of in a comfy subdivision by Parallax in California.
What kind of reward? He eats shrimp, from Costco. Or was that Browser's favorite? I dunno. I can send him something else to eat if you want him to be thanked state-side.
Ken Gracey
Hello!
Food? A very large amount of shrimp, not necessarily from Costco (Which I do know got started over there, their brand name is Kirkland, and that's one of the towns in the SETAC area.)
The clew was of course from Gordon, and of course Browser being an honorary moderator.
-Phil
BTW, the Propeller Backpack was totally Ken's idea, although the Elbonians embellished his original concept a little with feature creep. He was also responsible for the product's name. The Elbonians wanted to call it the "HoboProp", which would surely have condemned it to instant obscurity. (The Elbonians are good engineers but know nothing of marketing.
Hello!
Correct, the screens are standard ones. The locations are http://www.sparkfun.com/products/8448 this is the PSP one, and the other one:
http://www.sparkfun.com/products/8977 of the two, the second is closest to what I'd need.
According to the product page for 8977 it simply requires a good analog to digital conversion on two pins and 5v on the others. But that's where I'm stuck in a cave.
Since that touch screen is purely resistive, it should work just as well with 3.3V as with 5V. Basically, it's just a dual potentiometer, with the "wiper positions" being determined by the X and Y posiitons of a given pressure point. Each of the two outputs could be input to the Backpack's A0 and A1 pins on the Backpack's daughterboard connector, from where they connect to the onboard sigma-delta ADC circuitry. Here's where things get a little tricky, though. The input impedance of the Backpack's ADC is about 150K. To get a linear response from the touchscreen, it's internal resistance should be substantially lower than that. If not, you can either calibrate out the non-linearity in software, or buffer the touchscreen's outputs with a dual op amp.
-Phil
Hello!
My thoughts exactly. But the screen won't be ordered until much later. I'm going to be spending the time getting to know the backpack of course.