Encoder Front Page
SRS Home | Front Page | Monthly Issue | Index
Google
Search WWW Search seattlerobotics.org

First Steps: Setting the Stage for Building a Robot

Doug Leppard (DLeppard@CCCI.Org)
Benjamin Leppard (Benjamin@Leppard.Com)

I will be doing a series of articles outlining the steps we have taken in building our robot. Both Benjamin and I are newbies at this and thus it will be written for newbies. Articles will be focused on a robot that will compete in the Fire Fighting contest, be able to roam around the house and just be a fun learning tool. The 68HC912B32 is our processor, so articles will be on interfacing to the B32 to various mechanical devices and sensors using Sbasic as our programming language. Who are we?

We are a father and son team. I (Doug) am the father old enough to have a son in college. I am an Electronic Engineer by training and I direct the international division for information systems of Campus Crusade for Christ. As a hobby, I built my first three computers from scratch, called Home Brew in those days. My son,Benjamin, is a second year Computer Engineering student at UCF (University of Central Florida). I am the main builder with my son the consultant, who has put me many hours ahead on this project with his extensive knowledge.

Why a robot?

Count on it, if someone finds out you are building a robot they will ask why and what will it do. Almost no matter what you say it will do, it will leave them cold. It will never do enough to meet their movie expectations. Plus they don’t, for the most part, understand the why of building a robot. You and I do because we want to create and explore and we like the challenge. So I tell them that I am entering the computer in the Fire Fighting contest. This is something they can understand plus it gives you me goals to shoot for.

My real reason for building a robot goes back to a night when I was in grammar school and stayed up dreaming about it. It has taken 35 years to become a reality. This is actually my second attempt at a robot. The first one was a couple of years ago based on an IBM PC 386SX. Weighted a ton, actually moved around but the CPU ate too much power and would not stay alive for more than minutes at a time. It was a failure in the robot sense, but I gained knowledge especially on what not to do.

Setting your goals

In any project you need to set goals or you will just wander around and maybe accomplishing nothing. So you should have goals that you can aim towards. It may be small (fire up a micro and turn on a led) or large (enter a contest). If it is a large goal then it needs to be broken down into manageable and achievable goals or discouragement will set in. Steps in setting your goals maybe:

For example our goals are:

Main goals

Sub goals

Principles in building a robot

Conclusion

Have fun working on your robot, it will be a worthwhile experience.  The next article will be on the choice of the 68HC912B32 and why; choosing the programming language and choosing the CPU kit. It will be hopefully a lot more into making it happen. Future articles after that will include: using Sbasic with the B32 board, hooking up H bridge wheel drivers, using an RF link to/from PC to robot, using the Victor compass and wheel encoders.

Encoder_Doug_and_Benjamin_2.jpg (6647 bytes) Doug and Benjamin in front of work area.
Encoder_tools_1.jpg (7867 bytes) ProbeScope and Digital Logic Probe.  The ProbeScope was great in testing and debugging the shaft encoder.  It hooks up to your computer and uses it's power.  Only problem is on my notebook computer has only one RS232 port.  I could freeze the signal and analysis it. 

The Logic Probe is great for testing CMOS logic.  You can test if it is high/low or pulsing and shows the results using both LEDs and sounds.
Encoder work area.jpg (21981 bytes) Work area.  Not a lot of space but it does the job.  Far left is all the books on the shelf.  The two notebooks on floor is the documentation.  The table is left over from the kids home school days.

Bins are to the right.  I can't seem to figure out where to put the Nuts and Volts Magazines.   They are so oversized they don't fit anywhere.

The important thing is keeping everything within reach so time is not lost getting up.
Encoder tools 2.jpg (24953 bytes) I bought this protoboard over 23 years ago (what else in electronics can you use 23 years later).  It is great for protoboarding new circuits.  It has 5V, -12V, 15V unregulated.

 

Research:

(I did a lot of research on the Net.  Below are some notes I kept in a Word file.    No real order just random findings with some comments.  You may find it useful).