Private bot - which PIC microcontroller?
 

Hi there.
as you all know.. the season is over :mad:
and if you can't get a job.. summer vacation can be boring :)

SO => ME => BUILD ROBOT! :D
I'm quite new to microcontrollers..
but I think I have enough experience for what I wan to do:
a simple robot.. operated using onboard-buttons.
but I'm not so sure which PIC microcontroller is best for the job.

so.. from your experience.. what fits best?
requierments:
the ability to provide 4 small DC motors (I'll get those later)
EEPROM - important!
and that's about it..

thanks again..
Ran.

Re: Private bot - which pic?
 

I suggest getitng a VEX controller instead, lots less frustrating for a first project. PICs are a summer project in themselves, without a robot.

Don

Re: Private bot - which pic?
 

thanks for your reply,
actually, my plans are to play with regular pics this summer,
but as I'm a bit limited, I would like to know what are your recommendations.

:)

cheers,
Ran.

P.S do you have experience with PICs?

Re: Private bot - which pic?
 

I suggest if your going to get started with PICs is to play around for a couple weeks with a 16f628a and a programmer,and a bunch of leds. Try finding a copy of Picbasic Pro, it basically allows you to program a PIC like a basic stamp, so you don't have to worry about all the C syntax.

Re: Private bot - which PIC microcontroller?
 

If you know C then you can probably start with 18F series and use MPLAB and the C18 compiler to get started. Get a cheap programmer from sparkfun.com.

You can use the 2004+ RC code as a guide for developing your own. All 18F series have the same core structure, just different hardware peripherals.

Re: Private bot - which PIC microcontroller?
 

www.machinescience.org has a great set of tools for PIC programming based on the PIC 16F877. I think you can still get free FIRST accounts for their web-based IDE. They've streamlined a lot of the programming by having a bootloader and serial programmer, similar to how the FRC controller works, but the microcontroller is fully-functional and you write code for it just like you would in any other development environment.

What are you using to drive the DC motors?

Edit: http://www.machinescience.org/firstoffer.html

Re: Private bot - which PIC microcontroller?
 

I believe the 16f84 and 16f877 are the 2 good begginer PICs. But why a PIC? Why not an AVR? or a BASIC Stamp?

I know from expirience it is much much easier to start with an AVR. it is the same thing as a PIC but made by atmel and not microchip. You can go get a programmer for 50 - 80$ if you want the best cheap board. if you wanna go cheap you can easily go to 20$ for the programmer. the compilers are free, ad there is even a huge underground world for AVRs.......www.avrfreaks.net

-John

Re: Private bot - which PIC microcontroller?
 

hi, thanks a lot for your replies.

(sorry it took me so long to respond)..

so, I got my hand on a cheap Microchip PICKIT2.
+ a bunch of 16f690s.

played a lot with it, and currently learning the basics of PWM signals.

ZZII, I had no idea that there are offers like this,

what does this offer actually provide?
forwarded it to me "superiors" :D

John,
thank you, looks cool, but too late for me.

thanks a lot!!
Ran.

Re: Private bot - which PIC microcontroller?
 

i'm working on avrs (specifically the 169, as found in the butterfly) for my summer project. butterfly is a nice $22 board with a screen, speaker, etc., plus open-source starter code for all of the built-in functions. you don't need an expensive programmer, just solder up a three-pin connector to serial (i can send you in the right direction if you decide to go this route). AVRs are more powerful and built for C, while PICs are generally built for Assembly, which is a pain and not really relevant to FIRST at all (I hope).

Hope this helps!

Re: Private bot - which PIC microcontroller?
 

I really wouldn't recommend using a serial cable. Just get one of their cheap programmers (Dragon/STK500) and you won't have to deal with any problems with the home built ones. They will help you get started much faster.

Re: Private bot - which PIC microcontroller?
 

I would recommend an Arduino, It is a little board with an ATmega8 or 168 and a built in programmer, so you get it and its ready to work. There are USB and serial versions. All of the code open source and you program it in C. It supports everything you need it to do.

Re: Private bot - which PIC microcontroller?
 

yeah, i know that feeling. BUT if you have some pins lying around and you know how to use a soldering iron, it isn't really THAT bad.

Re: Private bot - which PIC microcontroller?
 

Yeah but it's so much more useful because of the number of different ways you can program the Atmegas. Also, you might accidentally program the fuses in the chip in ways that you can only fix by using a commercial programmer.

Re: Private bot - which PIC microcontroller?
 

The butterfly has a built in boot loader and already pre-assembled. Which means you can't take the uC off. Soooo....the serial cable si the only way to program it. Check it out.

http://smileymicros.com/

The arduino is nice. It is basically the BASIC Stamp of the AVR world. I looks like you can only program it using the "arduino language" which to me is not good. It is better to learn how to do it right the first time. I also can't find a price for it.

The stk and dragon are nice, but they are nor rally made to be put onto a robot. They are good to use as a ISP programmer if you have a seperate board with ISP headers, or if you have a chip that needs to be flashed then put into a socket somewhere. But I have found that with my STK since it has no holes and no other good way to mount it anwhere that I use it strictly for a dev. board.

-John

Re: Private bot - which PIC microcontroller?
 

No it isn't the only way. Look at the documentation again for the Butterfly. You can either program it using an ISP or a JTAG programmer. High voltage parallel programing is also supported but I have no idea why anyone would want to go that route unless somehow you screw up the fuse settings. Some assembly is required though because all of the ports are missing the header pins. I've used JTAG to program microcontrollers before. It's so nice seeing the program run and watching the registers change on the computer. I didn't actually say it should be placed on a robot. The dragon is just a bare bone pcboard with no way of mounting anything to it without some more assembly.
http://www.sparkfun.com/commerce/pro...oducts_id=8164

Re: Private bot - which PIC microcontroller?
 

I never said you did say to mount it on the robot. I am just that that is one down side. I know what the dragon and STK are. I have used them both and own an STK.

I didn't know about the JTAG because I have never used it. From the stuff I hear about it I should start using it to at least debug programs. From my understanding you can run the program on the uC step by step from the computer?

-John

Re: Private bot - which PIC microcontroller?
 

But Im really confused. The fact that you can't mount the STK500 and the Dragon onto a circuit board isn't really a disadvantage. I can't even think of a reason why you would want to. Yeah. I remember using the JTAG port in that regard on a DSP. It's really quite nice because you can see the actually ports on the microcontroller change in response to external stimuli.

Re: Private bot - which PIC microcontroller?
 

Well there are many reasons. Me an everyone I know that uses them wishes they could. It is a development board. which means it is used to develop there have been more then a few project where we have needed to just mount it to a robot really quick so we can have a PWM pulse gen on the bot. But it was harder to mount this. Now don't just go and say create a PCB because we needed the serial port for the USART, etc. It isn't something that is permanent. But it certainly would have helped.

-John

Re: Private bot - which PIC microcontroller?
 

The Arduino is has a bootloader that emulates an STK500, and a standard 6 pin ISP header. The "Arduino Language" is just some functions that they include to make it easier to program, you can add in standard avr code, or not use the arduino stuff at all. I like the arduino because it is pretty good for prototyping things, I recently purchased a STK500 and dragonfly bundle from digikey and i still use the arduino more.

Re: Private bot - which PIC microcontroller?
 

That solution sounds a bit expensive. If the Arduino's source code is open source might as well turn any of the Avrs that it supports into a a boot loadable device because essentially that is what you are paying for.
That really wouldn't be the way I would do it though. Namely because it's $80.00 which is cheap for what it does but not cheap enough that Im willing to stick it on a robot. The Dragon has no use on a robot because of it's limited prototyping area.

Re: Private bot - which PIC microcontroller?
 

You seriously still don't get it do you. If I were to add the open source bootloader to a AVR device I would still need to make a PCB for it (I don't know if your directing this at me or the other kid). It isn't like I put it on with a piece of scothch tape and entered it into battlebots. we set it on the robot so that we could test the motor controllers. The robot wasn't even moving! There is no way it could possibly get damaged. If You still don't understand what I'm trying to say I don't think you ever will.


-John

Re: Private bot - which PIC microcontroller?
 

I was directing that at the person who used the arduino.
Yeah but you said you wish you could mount it to something. Why would you need to mount it to something if the robot isn't even moving?

Re: Private bot - which PIC microcontroller?
 

Because the robot has uneven surfaces, and we were moving the electronics board from the desk to the to of the bot.

Anyways. Isn't my post supposed to put my opinion into the discussion. That means it is my opinion that it is a disadvantage. So why do you care. In all honesty if I want to strap my 80$ board to something, then why would you care? Maybe I am rich and have 20 of them to destroy. Maybe I'm just stupid. Either way, I still would like for them to have mounting holes on it.

-John

Re: Private bot - which PIC microcontroller?
 

I want to support karlcswanson on recommending the Arduino. I've used it quite a bit for little projects, as well as a field controller for a small VEX competition I arranged for my team. I'm currently working on using it as a navigation engine for FRC. Some thoughts to set the record straight:

1. The URL you posted is for the Arduino Stamp, which is probably not what you want to use. This URL at Sparkfun goes to the USB version of the Arduino board which is what I use:
http://www.sparkfun.com/commerce/pro...roducts_id=666
Notice that it is only $35, has power input, a USB program port, and a number of headers you can use to connect to a breadboard for prototyping. There is a shield you can get/make that connects right on top so that it looks just like the BS2. It can also be powered from the USB port.

2. The PCB comes with this version, and has mounting holes if you are concerned about it.

3. From the standpoint of developing a robotics platform for yourself, the Arduino has plenty of power but also plenty of room for customization. It will output a PWM signal, but it might take a bit of work to make it work with a servo. The Arduino language gives you full access to the digital outs of the ATmega -8 and provides delay functions which you can use to write custom functions to output PWM signals for servos, Victors, etc. The language is constantly being updated, and recently included support for interrupts.

The Arduino worked great for me in giving me insight into using microcontrollers and their peripherals - I definitely recommend it to a beginner since the hardware/programming/environment is so nicely put together.

Re: Private bot - which PIC microcontroller?
 

Thanks for the detailed input of someone who has used for some real applications.

If you or anybody for that matter would like help with programming or getting started in programming with the AVR micros feel free to PM me or IM me on aim @ sparksandtabs or email me at jgutmann340 AT gmail DOT com I have used them to a very very in depth level. Both with working with robots to just playing around with things.

-John

Re: Private bot - which PIC microcontroller?
 

A little off subject, but is anyone or team using the Parallax Propeller? They make the sequential mpu's, in your discussion obsolete.

Re: Private bot - which PIC micro controller?
 

For something a little different and on the edge you might try the "free" Microsoft Robotics Studio, a laptop with a game controller and zig bee dongle, and this board http://www.roboticsconnection.com/pc...ontroller.aspx Start with the visual programming language and get something moving. As you progress the VPL can generate C# code for more advanced work. Look at this system. Could this be the future First controller? Billy boy has put a little of his wealth toward First and robotics lately.

Re: Private bot - which PIC microcontroller?
 

If you can give us an update, how do you like the HitecC compiler for the 16 series parts? Better/Worse than MCC for 18 series?

<picrant>Its good you chose a PIC microcontroller over an AVR or Freescale etc. If you want to drive a victor from the PIC you can run your signal STRAIGHT OUT OF THE MICRO thanks to the high drive currents from PICs... AVRs n such need emitter/follower amplifiers to drive victors.</picrant>

Another question, these motors your driving, Are you using your own PWM board? or are you using a drive of some sort? ?

Are you using the onboard ECCPs in hardware PWM mode or are you doing it in software?

Thanks,

-q

Re: Private bot - which PIC microcontroller?
 

I got to play with a PIC18F452 in an embedded controller class in college -- we built everything from a TRIAC circuit to an alarm clock to a Ford Escort ECU manipulator.

I've also read specs that on of the 16-series PICS is used in the original XBOX as an encrypter/decrypter.

Lots of fun stuff to do with a PIC, though the external platform interfaces are becoming outdated.

Re: Private bot - which PIC microcontroller?
 

I like that comment I'm going to steal it.

That is not my understanding. The "wiring" language is not the only way to program the Arduino. It does come with the bootloader which supports the wiring language concept. You can replace the bootloader with whatever you want and use it like any other AVR 168 microcontroller but you'll need to use one of the hardware programmers instead of programming through the serial or usb connections.

I think of the Arduino's wiring language as being much like the WPILib library for the Vex and FRC controllers. They isolate some of the complexities of microcontroller programming in an easier to program language. Much like WPILib, the Arduino's Wiring language is C programming with a library to make writing programs easier.

I think the Arduino is a great choice for high school students to expand their robotics capabilities. At $35 each they are easily affordable for home use compared to $150 for a Vex robot controller and $450 for the FRC controller. You still need the $100 Easy C programming kit or the $50 Microchip C Compiler (or both if you choose) to make the FIRST controllers work. With the Arduino the programming tools are free.

There are several sources for the Arduino but Make Magazine sells them on their website at www.makezine.com or Sparkfun at www.Sparkfun.com.


Vince