Thoughts ?

mattm_nscc

Hi, I am looking to get a microcontroller soon, I know the parallax people might not like this thread so i apologize. I have experience with the BS2 through school use but I want to get my own. What i really want to build is an paintball sentry gun, because i play alot of it. I just wondering what other kind of microcontrollers are on the market.
specifically the Arduino's. I am wondering if the coding is any different then the BS2 I assume all Microcontrolls follow the same kind of general coding structure , and can the arduino do everything the BS2 can , likely I will go with the BS2 but I just want to hear some other thoughts on the subject.

Mike Green

There are all sorts of microcontrollers on the market. You can do your own web searches or look in some of the hobbyist magazines for advertisements for them. Some of them are specifically designed to compete with Parallax's Stamps and their programming and physical layout is very similar to that of the Stamps. There are many other microcontrollers that are programmed in one or another versions of C. The Arduino series works that way. A lot of microcontrollers, particularly the smaller, cheaper ones are also programmed in their assembly language.

As you've learned from your experience with the BS2, Parallax provides a huge amount of educational material for their microcontrollers and supports their products. They're easy to use and are reliable and well made. You can call or e-mail Parallax and get help from real people if you need it. These forums are heavily used and most people (based on their responses) seem to be pleased with the help they get. The same isn't always true with other manufacturers' products and other microcontrollers. You can certainly decide to use an Arduino for your project. That's not a bad choice, but you have to weigh the support issue into your decision making.

Franklin

My thoughts on hardware (microcontrollers and such) is that they should be the last thing you pick. you need to figure out what you want to do, how you plan to do it, what input and output you need, how you will get that. Then you pick a micro that will be able to process those inputs and outputs at a speed that will allow you to accomplish your goals. Hope this is helpful.

bill190

I googled "paintball sentry gun" and this sounds like a paintball gun which will automatically find targets and then shoot them with paintballs?

I found the following page on this...
http://www.paintballsentry.com/StarterKit.htm

This type of thing sounds like a highly sophisticated system for which the "brains" need to run on a PC.

And you would have input to the PC from something like a camera?

And output from the PC to the paintball gun to make it move, fire and so forth.

Are you wanting to write all the software to do all of this?

Or do you already have software for a PC and just need the microcontroller to control the paintball gun?

P.S. Something like this would be fun to attach a water squirt gun to. Or maybe a flood light and have the light follow people walking up to your front door, follow the dog around the yard, etc.

Mike Green

The "brains" don't always need to run on a PC. The CMUcam (several versions) has a built-in microcontroller that does some basic video processing and can, for example, follow a ball using a servo-driven camera mount. The positioning information can be used (with another microcontroller, like a Stamp) to drive another mount with something else on it. I believe Kye was working on a Propeller-based update of the CMUcam. You might look for his thread on the subject.

Microcontrolled

This looks like a candidate for the Propeller, if you are up for it. The Prop can handle some processing itself, plus it can communicate with Viewport and OpenCV to give you full image recognition. Open CV is what is commonly used for such systems.

mattm_nscc

Thanks for the advice, i think i probably go with another BS2, since im fimillar with it and it will be easy to learn, and theres lots of support.
I would like to be able to maby modify it so it could be wirless, I wouldn't want my laptop sitting on a field in play

J^3

Depending on the level of sophistication you would like to have there are many paths you can take. If it were me doing the project, I would try to start simple and use ping sensors spaced every 45 degrees around the base of the sentry gun, and some sort of gearbox to rotate the paintball gun 360 degrees (Servo system, stepper motor, etc.). The target's position, and direction of travel could be determined from which Ping sensors are indicating movement. From these readings your micro of choice could determine the fastest way to rotate the paintball gun in order to intersect the target. Of course this simple system would target friend, or foe.

The BS2 could easily handle these tasks, and it comes with an impressive support community to back you up as Mike has stated above. I would probably pick a BS2P40, easily giving me room to have plenty of sensors along with room for expansion. If all goes well with rev1, then try to use some sort of image processing once you feel more comfortable with the device you are using.

Duane Degn

Matt,

This project is crying out for a Propeller.

Yes, different microcontrollers have their advantages but (IMO) the Propeller is such a great fit for so many projects that you don't really need to worry about learning to program the other uCs since there are few things the other uCs can do that the Prop can't do. The Prop can run circles around an Arduino (and the BS2).

I hear people say that the Prop is overkill for some projects but who cares? The Prop is much less expensive than a BS2 so why not overkill your project?

A QuickStart board costs $25. You can start programming it right away since it communicates to the PC through its USB connection. The USB also provides the QS with power. You can add a battery pack to the QS once it's programmed to free it from the computer.

Take a look at the "Machine Vision" links in my index (see my signature). I think the Prop could handle your machine vision needs without a PC.

You'll also get lots of help with the Prop on the Propeller Forum. Get a Propeller! You'll be glad you did.

Edit: I hadn't seen J^3's post when I made this post. It was not my intention to contradict what J^3 said.

erco

Duane Degn wrote: »

Edit: I hadn't seen J^3's post when I made this post. It was not my intention to contradict what J^3 said.

Eloquently worded and very well-intended, Duane. I will remember to use this laudable approach next time I get passionate and step on someone else's more timely post. Whether I ever saw it or not!

It's kind of like when I end a snail mail letter with, "I meant to enclose five dollars with this letter, but the envelope was already sealed."

J^3

Duane, thank you for your considerate response.

Matt,

I had another thought on the friend, or foe problem. Simple beacons can be issued to team mates which would disable the sentry gun when they are in range of the sentry. Might be getting to expensive though.

The prop is also an excellent tool as Duane has suggested. Obviously, the prop has the same support community as the BS2.

mattm_nscc

Hmm this defently deserves some more thought. The site Bill metioned is what i was looking at getting the controler for and i would build the rest. Do u think it would be possible to make that wireless?, say with the Xbee pro and get it wirless so only the controller is there and the Xbee with the program is on the laptop in my car, say a 1/4 km away ?