the future of the propeller...

omgitsaliv55

Hi everyone. I've been using the boe bot for about two years now and love it. I've always felt very comfortable developing for it because I know that theres a plethora of documentation out there and someone will almost always know the answer to the question i have (whether that person lives next door or is halfway across the world). When the propeller was first released, I kind of "poo-pooed" the idea of embracing it as something new to learn and just kept on going along the path I was already taking (with the boe bot). After 3 more months, I had pretty much done everything I could with the boe bot without buying some expensive accessory that I would use for a week. I had enough programming experience to understand a language like SPIN, but because of the fact that the propeller was still more geared toward home brew robotics I shied away from it. I figured that if I held out long enough, there would be a kit similar to the BOE-Bot that didn't assume much prior knowledge at all and was geared toward the beginner. I know there are a lot of people who will disagree with me, but it's a little less than two years after the initial release of the propeller and we are only starting to get out of the home brew stage. I'm not bashing the propeller; I think it's great. What I'm saying is that I'd like to see it marketed a bit better.

I've placed my order for a propeller education kit along with some other accessories and I plan to solder a board together similar to the board of education. It will have servo ports, a breadboard, nice power supply adapter, and all of the things you would expect from the ideal development board. It will have a small form factor, and will have multiple DIP sockets for things like the Propeller chip (40 pin model), voltage regulator(s), EEPROM, other essential parts that allow the prop to function, and an area to plug in servos/accessories which will be connected to the 5 volt voltage regulator. I chose to make parts like those DIP because things break and it really sucks to have to buy a new board because one damn component broke.

I'll also create code that will make it function the same way as the Boe Bot (object avoidance, line following, light seeking, etc). It will use the same chassis, parts set, etc. with the exception that the Propeller is used as the MCU.

If all goes well, I think I will write a manual similar to "Robotics with the Boe-Bot" but for the Propeller. It will cover everything from servos to resistors, I/O pins to memory management.


I know all of this sounds extremely stupid, especially that last bit. I'm totally aware of the fact that there is a manual for the Propeller and the SPIN language, but that's not really suficient for the beginner roboteer. If anyone has any ideas, suggestions, or would like to stay updated or learn how they can make a board like this themselves, let me know and I would be happy to to start a blog or something like that. Also, if Parallax is already working on this and I've just been living under a rock, let me know because I don't want to put a years worth of work into something that will be coming out in three months. Thanks!

-Patrick

Post Edited (omgitsaliv55) : 4/20/2008 1:03:21 AM GMT

Mike Green

I would suggest starting with a Propeller Protoboard. It already fits the mechanical layout of the BOE. There's a special version of FemtoBasic for the BoeBot chassis that includes support for a PING))) on a servo bracket, HM-55B compass, IR distance sensing, SD card, and a wireless control link using an xBee transceiver. The Protoboard Accessory Kit includes connectors for up to 3 servos.

There's a thread about it with pictures here: http://forums.parallax.com/showthread.php?p=635533.

You could easily mount a small breadboard with headers for some I/O pins, Ground, +5V, and +3.3V on a small bracket above the Protoboard and run a jumper between them. I added an I2C I/O Expander to handle the compass while leaving the VGA, keyboard, and mouse connections available and there are some uncommitted I/O pins on that. It would be trivial to add a second I/O Expander to provide signals to the breadboard.

This BoeBotBasic would be a good basis for an introduction to Robotics using the Propeller. You could move from that to Spin programs as you developed more complex systems.

stevenmess2004

Mike, the proto board actually has connectors for up to 4 servos .

I think part of the problem with the propeller is that it can do too much and people tend not to think of using it for simpler things. I mean, why would you use it for a robot when you can use it to drive a tv or monitor?

Mike Green

Actually, you can do both. I've tried transmitting a TV broadcast signal from the Propeller BoeBot board. It's a noisy signal, but works with a large font and works better if you substitute a 6MHz crystal for the standard 5MHz one (because the TV channels are spaced at 6MHz intervals).

stevenmess2004

What kind of range did you get out of it Mike?

Mike Green

I got a range of 3-5 feet with an untuned short (roughly 6") whip antenna

omgitsaliv55

stevenmess2004 said...
Mike, the proto board actually has connectors for up to 4 servos .

I think part of the problem with the propeller is that it can do too much and people tend not to think of using it for simpler things. I mean, why would you use it for a robot when you can use it to drive a tv or monitor?

That's a good point, but you also have to remember that SPIN is a prettier language than basic. Of course basic is much simpler, but spin requires you to organize your code better. That way you have code that is expandable, and not just full of routines. In the end, it allows you to do more with a robot than you could with a basic stamp. I did worked with a lynxmotion BRAT using a Basic Atom Pro (very similar to the basic stamp 2, just faster, more ram, used flash, and 4 more I/O), and it was not easy to get that thing walking the way we wanted to. It's not that I didn't know how to do it; it was the fact that BASIC is so...basic that we couldn't manipulate data the way a language like C or SPIN can.

the basic stamp is good for robotics, but a propeller would make things even better.

Mike Green

By the way, BoeBotBasic was originally developed for use with the SpinStamp. Even though Parallax doesn't support the use of the SIN/SOUT pins for serial I/O, it worked with my Keyspan High Speed Serial Adapter and I could use the BOE's DB-9 programming port for serial communication with Spin programs. You have to be careful with the SpinStamp's 3.3V logic inputs with 1K series resistors when they're talking to 5V output devices, but it all seemed to work.

Paul Baker

omgitsaliv55 said...
If all goes well, I think I will write a manual similar to "Robotics with the Boe-Bot" but for the Propeller. It will cover everything from servos to resistors, I/O pins to memory management.
-Patrick

Hi Patrick, thanks for deciding to take the plunge. We welcome all customer generated material, while there is the manual it doesn't go into any application specific information. Before you get started writing, look for the stuff other people have done. http://search.parallax.com , look for PropBot and Propeller + BOE-BOT. You may also want to look at other customer generated references, OldBitCollector (OBC) has a series, and deSilva has one too. They are concerned with more general topics, but it might spark some ideas for your project.

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.