View Full Version : Prop Bot

Ken Gracey
02-02-2007, 02:17 AM
Hey there,

Regardless of the unique commercial applications of the Propeller, we have a proud commitment to our customers to put·everything and anything·on a robot chassis. This is a picture of the Prop-Bot.

I built this robot for a customer in Europe using the Prop Proto Board and Boe-Bot chassis.·I miss the breadboard for quick wiring, but as long as I·build the circuit·correctly, the through-hole PCB should provide for greater opportunities with robotics: parts won't fly off the robot and there's more room·for·circuits. I haven't written any Spin code, but others have produced objects that I will use.·I'll start in on that this weekend.

For now I'm just living up to my reputation as a marketing guy and showing you·a picture.


Ken Gracey
Parallax, Inc.


02-02-2007, 04:42 AM
I was thinking about doing this with my demo board, but there are no standoff holes (maybe a suggestion for rev. G). Anyway, has anyone figured out a safe way to mount the demoboard?


Mike Green
02-02-2007, 04:46 AM
I used two layers of double-sided sticky tape with a blank PCB that fit into the space. I drilled holes for the screws for the standoffs. Worked great (and came off fine later with a little work).

02-02-2007, 04:58 AM
I think it needs the composite DAC and a bit of wire for a wireless status display, maybe boe-dar like

Who says you have to have knowledge to use it?

I've killed a fly with my bare mind.

02-02-2007, 05:46 AM
Nice :)
I personally dislike those small breadboards. You run out of space fast and they feel insecure. What I'd probably do, should one of those boards fall in my hands, is make some sort of adapter to for row of 3-pin male headers. Most sensors and effectors will just need 3 pins. An exception are those pesky SRF04 sonars, but you got Pings. Another one are RS232 interfaced sensors (if you need both rx and tx), like the cmucam, but there are less of those. Perhaps 4 pin headers would be good to, you could use the extra pin to "polarize" the connectors.

Ken Gracey
02-02-2007, 06:11 AM

The breadboard / through-hole issue for robotics is a big one for many of our customers. We've trained them on the Boe-Bot and they've fallen in love with breadboard-based robots. It's just so quick to put the whole circuit together, especially in a classroom setting. Andy's books let them build it, program it, and customize it all within a 2-hour period.

Good point about the three-pin male headers. The Prop Proto Board has locations for four of them already, though you can go bananas and put them elsewhere too.

CJ nutcase:

Love the avatar! We have a PARALLAX neon sign in our demo room that I built several years ago. The marketing people are stealing it away and taking it to the new Aerospace Museum of California, where it shall reside in a permanent location with our robots. Your avatar inspires me to make a neon version of the Propeller logo. I couldn't envision it in neon until I saw your logo, since our version has solid colors.

Ken Gracey

Dennis Ferron
02-02-2007, 07:39 AM
When I built a Boe-Bot for my professor, the "part's falling off the breadboard" issue definitely concerned me, especially since I wouldn't be around to fix it later. So what I did was I cut the leads to the components short and kept everything hunkered down to as low a profile as possible so that things would not come off. I added an LCD display to the front of the robot, with menuing software and 5 selectable programs, and even custom built a gripper as a little "extra" that goes on the back side of the boe bot. I thought I did a good job, but he said, "But you haven't left me room on the breadboard to put my bluetooth module." Well drat! There's only so much I can do with a 2 inch breadboard. Still, some people are nervous about picking up a soldering iron, and I can see how soldering could be a problem in a class environment if the robot is going to be used and reused, so the breadboard helps in that respect. Though, honestly, from most of what I've seen, you're lucky if you can find a class with enough motivation to build a robot one time, let alone have the robot see multiple revisions.

02-03-2007, 02:08 AM
Yeah, I agree that for a classroom setting and quick prototyping breadboards are a lot better. Apart from some people being (justifiably) nervous about picking up a soldering iron, even if you teach the students how to solder, it'll take a while for them to get it right, and in the meanwhile all you're going to get is bad solder joints that can cause a lot of frustration.
I thought I knew how to solder, but looking back a lot of my soldering work isn't very good and after a while has started to fail intermittently. (In my defense, I used really bad soldering irons :)). A friend who is into R/C car racing and absolutely needs top performance from his connections gave me a few good pointers. Some of them are kind of overkill, though (he uses Dean's plugs with gold-plated connections and some super-expensive solder and wires). Dean's ultra plugs can carry 50+ amperes. I don't need that much, of course. I've gradually converged on the relatively inexpensive combination of male headers for boards, and female-header (servo-like) connectors for the sensors/effectors. I bought a cheapo crimper from Jameco to make them. But it does a few tries to learn to make those, too. And they're not polarized (important when sleepily connecting things at 4 am!).
With more $$ a better idea might be to do something similar with Molex-style items, which are better quality and have polarized connectors.