Society of Robots - Robot Forum

General Misc => Misc => Topic started by: Mega on December 09, 2007, 05:54:40 AM

Title: Newbie
Post by: Mega on December 09, 2007, 05:54:40 AM
Hi robot fans!

I'm new to this forum. I am Mega, a robotics fan from the Netherlands.
The last year I've been working on a number of hobby robot projects.
My last project is to create a HummBot, a robot hummer (model) car which can find its own way through a obstacle track.
For more information about my projects see http://megabotblog.blogspot.com/ (http://megabotblog.blogspot.com/)

This forum looks great, and I hope to learn a lot from you guys!

Best regards,
Mega
Title: Re: Newbie
Post by: cooldog on December 09, 2007, 06:46:32 AM
for your progect what are your programing capabilitys in C

depending i have a idea

also do you want your robot to follow a path you marked or just avoid walls and objects
Title: Re: Newbie
Post by: Mega on December 09, 2007, 06:55:55 AM
Hi cooldog,

My C programming is quite good, I've been programming in C, C++ and C# for more than 10 years.
My electronics knowledge is that of a beginner, but I can build some simple circuits on a breadboard.

I'm very interested in your ideas.

Mega
Title: Re: Newbie
Post by: Rebelgium on December 09, 2007, 07:09:06 AM
Hallo Mega,

I am from Belgium (Vlaanderen).
I recommend you read alot of the tutorials on this site, very inspirational :)
Browse the net for ideas etc.

And when you have questions, search the forum, google it, or post a new topic  :)

See you
Title: Re: Newbie
Post by: airman00 on December 09, 2007, 07:26:59 AM
My last project is to create a HumBot, a robot hummer (model) car which can find its own way through a obstacle track.

What does that mean an obstacle track?

For a competition I have to have a robot follow a line and avoid obstacles in its path, and retake the line again ( and avoid walls as backups to the line following sensors.

By obstacle track, you mean avoid obstacles and continue in the direction it was previously heading ?
Title: Re: Newbie
Post by: Mega on December 09, 2007, 07:37:11 AM
@Rebelgium
Thanks for the tip. These tutorials are really great. I read the wall avoiding Wallbot tutorial, excellent! This is going to be very useful for my Hummbot (http://megabotblog.blogspot.com/2007/12/humbot-start-your-engine.html) project.

@airman00:
Yes, with obstactle track I meant that the Hummbot (http://megabotblog.blogspot.com/2007/12/humbot-start-your-engine.html) heads in one direction and avoid obstacles on its way.
I've been inspired by the DARPA challenge (http://www.arpa.mil/grandchallenge/index.asp) where real robot cars have to find their way around a track as fast as possible.

Regards, Mega
Title: Re: Newbie
Post by: cooldog on December 09, 2007, 07:37:52 AM
to Can control the car with the $50 robot with sharp Ir upgrade circut you will have to change the code so that the Ir sensor makes it move away from object instead of towards and to use motors instead of servos
Title: Re: Newbie
Post by: Mega on December 09, 2007, 07:43:07 AM
@cooldog:
What exactly do you have in mind when you say "to use motors instead of servos" ?

Title: Re: Newbie
Post by: Ro-Bot-X on December 09, 2007, 07:48:42 AM
Well, the car that you're going to use has a DC motor for propulsion, doesn't it?
Title: Re: Newbie
Post by: cooldog on December 09, 2007, 07:58:30 AM
the $50 robot uses servos as motors instead of dc motors so the code is different because servos need a paticular pulse to opperate
Title: Re: Newbie
Post by: airman00 on December 09, 2007, 07:59:33 AM
Yea, mega  your R/C car runs off DC motors NOT servos

that complicates it a bit


if its not to late I would make a small HDPE plastic base and attach modified servos to them. It'll make your life much easier. Then afterwards add the car cover.

as for code , i would start from scratch and only take code for controlling servos and reading IR sensors for the subroutines.
Then in your code , you would just call up different subroutines
Title: Re: Newbie
Post by: Mega on December 09, 2007, 08:03:39 AM
Ok, I get it. I'm not familiar with the 50$ robot yet, I was just reading the tutorial...
Yes, the HummBot will use a DC motor for propulsion and a servo for steering, both controlled by an Arduino board.
I plan to control the DC motor via an H-bridge.

Btw. this is the most active robotic forum I've ever visited. It's great to see all the fast responses and comments. Excellent!
Title: Re: Newbie
Post by: cooldog on December 09, 2007, 08:32:13 AM
if you use the circut from the $50 robot you won't need the arduino board. the $50 robot board is about $50 but i don't know the price of the arduino
Title: Re: Newbie
Post by: Mega on December 09, 2007, 08:37:53 AM
One of the main reasons the Arduino is so popular is it's price: $38,95 at RobotShop.ca (http://www.robotshop.ca/home/products/robot-parts/microcontrollers/arduino-microcontroller/index.html).
Title: Re: Newbie
Post by: Rebelgium on December 09, 2007, 08:57:32 AM
Quote
Ok, I get it. I'm not familiar with the 50$ robot yet, I was just reading the tutorial...
Yes, the HummBot will use a DC motor for propulsion and a servo for steering, both controlled by an Arduino board.
I plan to control the DC motor via an H-bridge.

Btw. this is the most active robotic forum I've ever visited. It's great to see all the fast responses and comments. Excellent!

I've been browsing the net for robotics a long time, and this is just the best site... :) That's exactly why I'm still here :D
Be sure to mention SoR on your blog if we happen to help you ;)

Using servo's instead of DC motors would be easier, mounting everything on a sheet of HDPE ( and then mounting the hummer cover on top of it) would also be easier, and using the 50$ robot circuit would also be easier. But doing all this, you will not make your humbot, but the 50$ robot...


If you feel confident enough (I've seen on your blog that this is not your first robot) you should start with your humbot right away.
Using H-bridges and DC motors instead of servo's isn't THAT hard. And using the Arduino board is a great experience.

If you're not confident enough, make the 50$ robot first, an later the humbot.
Title: Re: Newbie
Post by: Mega on December 09, 2007, 09:37:51 AM
Quote
Be sure to mention SoR on your blog if we happen to help you Wink
I already added a link to this great site!

Quote
If you feel confident enough (I've seen on your blog that this is not your first robot) you should start with your humbot right away.
Using H-bridges and DC motors instead of servo's isn't THAT hard. And using the Arduino board is a great experience.
I will go for the DC motor, H-bridge and Arduino. I already found some nice tutorials that describe how to control a DC motor with an Arduino.
Next to that the the HummBot will weigh almost 2 kilo so I think using servos for propulsion will be quite challenging.
Title: Re: Newbie
Post by: paulstreats on December 09, 2007, 09:45:43 AM
I noticed at the bottom of that page the RP6. can you let us all know some info about it such as sensors etc...

If you built the rp6, I presume that the base is the one ive seen with motors already built into it, so you have experience with using motors already? Also I was led to believe by the ad for that base that there are wheel encoders built in, is this true and have you used them?
Title: Re: Newbie
Post by: Mega on December 09, 2007, 10:10:20 AM
I did not build the RP6 myself, I bought it pre-assembled. I have been experimenting with some small extensions and some programming.

The RP6 is controlled by a AtMega32 microcontroller, it has two IR sensors for distance measurements, two light sensors and two bumber sensors in case the RP6 runs into something. Furthermore the RP6 has two built in H-bridges to control the two DC motors. And yes, it has built in wheel encoders such that the RP6 can be moved across a specified distance in cm.

(http://img33.picoodle.com/img/img33/5/12/9/f_overviewm_9050b33.gif)

The main advantages of the RP6 are its robust wheel base and its high extensibility.
For more information have a look at the RP6 site (http://www.arexx.com/rp6/html/en/rp6.htm).
Title: Re: Newbie
Post by: Rebelgium on December 09, 2007, 10:52:17 AM
I had never seen the RP6, I really like it.
It's expandable, looks robust enough, simple but still with advanced possibilities...

If I wouldn't be making a robot base which is even better myself, I'd buy it. ;) ;D