ZappBot 0.2

zappman

Hi everyone,

ZappBot 0.1 is roaming around my house.

I have managed to cobble together enough code for the ZappBot 0.1 to roam about freely on the floor without running into things.

I let it roam for a couple of hours on its own.

For the time being it Pings around 180 degrees looks if the path forward is clear forward for 50cm, if so it moves forward a little. If the forward path is blocked it looks to see if the path to the left and right side are both blocked by objects within the next 30cm, if so, since the it is blocked forward, left and right, it backs up a little. If the path to the left or right is clear for more then 30cm, it determines which side has the clearest path and turns in that direction.

I have not bolted down any of the parts of the ZappBot to its deck everything is just being held down by its own weight.

The tail wheel can use some improvement, it tends to bias the ZappBot right or left just a little so it does not run straight, seems like it needs a better swivel bearing.

Click the link below to see a video of ZappBot 0.1

www.youtube.com/watch?v=HypeSaIreSA

Visit my ZappBot build Blog by clicking the link in my signature

Visit Zappman's Blog at Savage Circuits

Post Edited (zappman) : 7/6/2010 1:14:17 AM GMT

Martin_H

So it looks like you are using the board of education and a stamp as a your brains. Did you buy another or cannibalize it from the BOEbot?

I've been using the Ping on the bracket mount since May and really love it. Knowing distance and direction really simplifies navigation.

erco

Sweet ride, Zappman. You know I'm a huge fan of scratchbuilt wooden robots!

Nice sequence, it's fun to watch the interactive scan and resulting drive/turn behavior.

Great start. Be proud!

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·"If you build it, they will come."

zappman

@ Martin_H
Yes, the BS2 and BOE are off my BOE-BOT.
The BOE-Bot was just too small.
Using the Ping Sensor is really neat, especially when panned on a servo.

@ Erco
I know like scratch built wooden Robots.
I followed your entire build in the forums and have the magazine with your article.
I think building from scratch teaches you more, that's why I am doing it.
Another thing I agree with you on is 'Not understanding why the Parallax Big Robot kit needs ten Ping Sensors?'
This is just the beginning of my ZappBot.
I want to add a lot more stuff, including wheel encoders.
I looking forward to see what kind of encoders Parallax comes up for the Stingray.
The code on the ZappBot is my first try on original code (although it based on a lot sample code) and it can use a lot of work.

Visit Zappman's Blog at Savage Circuits

Whit

Hey Zappman,

Great job! Can't wait to see how it grows.

Per your comment to erco, I am looking forward to seeing the Stingray encoders myself. erco has become very good at making his own!

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Whit+


"We keep moving forward, opening new doors, and doing new things, because we're curious and curiosity keeps leading us down new paths." - Walt Disney

zappman

The new and improved ZappBot 0.2 is roaming around my house.

Per Whit's request, today I made have made it grow.

It is now 15.5 inches tall by 14 inches wide by 14 inches deep and has 3 decks.

The decks are mounted with 4 - 12 inch pieces of ready rod.

Now I should have plenty of space to mount stuff.

For version 0.2 I removed the single swivel caster and replace it two metal ball casters, they are attached with threaded standoffs to the rear pieces of ready rod.

I did this to try to make the ZappBot track straight.

I also lowered the left motor speed command value compared to the right motor speed command value, to try to make the motors run at the same speed.

What I really need, is some BS2 good sample code, of roaming with a servo Ping and HB-25 motor controls.

Coding is not my strong point, but I am working on learning it.

Click the link below to see a video of ZappBot 0.2

www.youtube.com/watch?v=a31h6C2QCgg

Visit my ZappBot build Blog by clicking the link in my signature

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Visit Zappman's Blog at Savage Circuits

Post Edited (zappman) : 7/6/2010 3:57:42 AM GMT

Martin_H

Zappman, that's neat! How much does it weigh?

I have some roaming code for the Ping and servos written for the BS2E. It uses the multi-bank feature so it would require re-work for the BS2 and your motor controller. But you are welcome to have it. I can upload it if you want to take a look.

zappman

@ Martin_H

Thanks, sure I would like to see your code, I have no idea what you mean by 'multi-bank feature', but, I am always willing to learn.

I just weighted the ZappBot 0.2 on my bathroom scale and it weighs about 10 to 11 pounds.

(I also added 4 pictures to my previous post).

To bad the long holiday weekend is over, tomorrow its back to work.

Visit Zappman's Blog at Savage Circuits

Post Edited (zappman) : 7/6/2010 3:59:32 AM GMT

erco

Nice progress, zappman! AFA straighter tracking, I think you'll have better luck adjusting your CG rearward toward your drive axle. You want to take weight off of your casters and keep as much weight on your drive wheels as possible.

When I worked on Retrobot, I was surprised to find that my 3" rubber caster from Lowes worked best for repeatable tracking, again with minimum weight on it.

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·"If you build it, they will come."

Martin_H

Zappman, I've uploaded my code to the "My CBA, Parallax, Pololu Mash-up Robot" thread. Take a gander at it. Comments and suggestions are welcome.

zappman

Martin_H, Thanks for uploading your code to the 'My CBA, Parallax, Pololu Mash-up Robot' thread. I am printing it out now, so that I can look at it.

Erco, thanks for your suggestions on the wheel positions and Center of Gravity. One of the advantages of building a Robot from scratch is its such a great learning experience.

These forums and all the people that help each other, is such a valuable resource.

Visit Zappman's Blog at Savage Circuits