go_away

Author Topic: First project  (Read 2343 times)

0 Members and 1 Guest are viewing this topic.

Offline Tomomastchi-projectTopic starter

  • Jr. Member
  • **
  • Posts: 20
  • Helpful? 0
First project
« on: September 24, 2008, 12:25:41 PM »
Hello guys,

I am currently in the design phase of my first robot project. I did not have a lot of experience yet but I already red a lot about electronics, microcontrollers and robotics so I have some BASIC knowledge.
What my(actually our, as I work together with a good friend of mine) idea was is a simple interactive pet-like robot. I already made up a lot of functions and algorithms that go with it but I have some questions, especially concerning the controller.
I came to the conclusion that the most suitable controller for my project is a PIC 16F877, programmed in C through the HIGH T assembler. This is where my first questions comes: 1. I want to build a simple programmer myself. What should I do? A JDM2 based one would be OK I think, but I am not sure. Shoulf I just build http://www.instructables.com/id/Business-Card-PIC-Programmer/ and connect to it using IC prog? It really doesn't matter to me what programmer I will build and what program it uses to upload as long as it works and it is easy to build(clear schematics and instructions seem to be absent at the site I linked to).
2 Is it going to be a problem if I use a PIC 17F877 A in combination with the programmer?
3 What is the most commonly used connector system in robotics. I ask this because I want to start off with some of the basic functions and then add extra sensors / actuators later on when I'm finished with the more simple tasks.
4 I have a book about C++ programming and I actually can do some C++ programming, can I just use the syntaxis of it and use the HIGH T functions?
5 What kind of motor suits best for a beginner? Just a regular DC motor?
6 I would like to know how a rechargeable lead battery is recharged. Do I just have to connect a slightly higher Voltage parallel over the battery? I want it to be able to charge and to function at the same time(when it is in a charge-dock, you see?).

Also I still need to make up a random number generator algorithm for the behavioral aspects, but I will first look through the programming section for that.

Those are the problems faced by me right now, I'm sure there will be a lot more.

Offline pomprocker

  • Supreme Robot
  • *****
  • Posts: 1,431
  • Helpful? 16
  • Sorry miss, I was giving myself an oil-job.
Re: First project
« Reply #1 on: September 24, 2008, 05:30:33 PM »
May I ask why you chose to go with a PIC?

Offline paulstreats

  • Supreme Robot
  • *****
  • Posts: 1,381
  • Helpful? 21
Re: First project
« Reply #2 on: September 24, 2008, 07:01:19 PM »
I would look at using the PIC18F4550 as a replacement and use the free microchip C18 compiler for the c language.

Also go to instructable.som and type "business card" into the search box. There is a schematic for an easy business card sized JDM programmer there that I give a 5 star rating for.

As far as motors go, a motor on its own wont be very good for a wheeled robot. they spin really fast but give little torque or pulling power. You will need a gearing system along with the motor. You can also buy dc motors with a gearhead built in. Definately shop around and research into this before commiting money to 1 particular system.

most distro's of C come with a standard libraries that help you generate random numbers easily e.g.
randomnumber=Rand(seed); Where seed is a value passed to a psuedo random generator (could be say the clock time or even link it to a sensor so the random seed alters along with sensor inputs)

the main sytax of C is the same as it is for c++ just without the expanded libraries and toolkits and lack of built in threading etc.. there are a few topic in the programming section that cover multi tasking with C. The biggest difference between programming computers and microcontrollers is that you need to know how to programatically modify the state of output pins and get the value of input pins on the microcontroller. This all comes usually by following examples etc...
« Last Edit: September 24, 2008, 07:10:07 PM by paulstreats »

Offline ArcMan

  • Supreme Robot
  • *****
  • Posts: 519
  • Helpful? 4
  • Mmmm... Plasma
Re: First project
« Reply #3 on: September 24, 2008, 09:07:48 PM »
Connectors...

I think every experienced robotics guy has certain connectors that he likes.  Of course, sometimes you're forced to use a certain connector, like the 3-pin 0.1" header connector for servos.  For stuff like I2C, 5V serial, small power connectors and other low-pin count stuff like that, I swear by KK series connectors.  I was introduced to them when I bought an OOPIC board.  They're like header connectors except they're keyed and they actually stay connected.

Offline Admin

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,699
  • Helpful? 173
    • Society of Robots
Re: First project
« Reply #4 on: September 30, 2008, 07:34:12 AM »
Quote
5 What kind of motor suits best for a beginner? Just a regular DC motor?
servos

Offline Tomomastchi-projectTopic starter

  • Jr. Member
  • **
  • Posts: 20
  • Helpful? 0
Re: First project
« Reply #5 on: October 01, 2008, 01:09:15 PM »
I found some great MOT 11 / Copal HG16-030-AA-00. These are 6V 450mA. They have a built in 30:1 gear. You guys think it is ok? We want it to be able to go back and forth, so I think we need an H-bridge?

Offline Admin

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,699
  • Helpful? 173
    • Society of Robots
Re: First project
« Reply #6 on: October 08, 2008, 05:56:16 AM »
Yea, you'll need an H-bridge. I recommend just buying a motor driver.

 


Get Your Ad Here

data_list