Society of Robots - Robot Forum

Mechanics and Construction => Mechanics and Construction => Topic started by: chelmi on December 17, 2008, 02:35:43 PM

Title: Polystyrene chassis
Post by: chelmi on December 17, 2008, 02:35:43 PM
Hi guys,

I'm currently building a small bot, very classic: differential wheels, a ball caster, ir range finder and a servo to scan. The whole thing will be controlled by an Arduino board.

I'm still waiting for the electronic parts to arrive (I won't tell you from whom I ordered them but let's just say they are known for their delays...). In the mean time I started working on the chassis. Here is the plan (the front is on facing down, size is about 125mm by 175 mm):

(http://garcimore1.free.fr/wordpress/wp-content/uploads/chassis.png)

It's not very clear but basically the big black boxes are the motor and the wheels. The proto board is in blue and goes on top of the battery pack.
I'm still not sure about the final layout. I would like to put the servo/ir sensor further back so the "dead range" of the sensor will not be right in front of the bot.
I will also add a few bumper sensors on the front and on the back.

What do you think?

As a material, I used polystyrene from a "food tray", the kind used to pack meat or fish. See what I mean ? I have one 4 mm thick, quite sturdy. Here is the current result:

(http://garcimore1.free.fr/wordpress/wp-content/uploads/dsc02507_1024.jpg)

(http://garcimore1.free.fr/wordpress/wp-content/uploads/dsc02508_1024.jpg)

(http://garcimore1.free.fr/wordpress/wp-content/uploads/dsc02509_1024.jpg)

My concern was ESD, but some people here say its probably not an issue. Hope they are right ;)

Comments are welcome!

Chelmi.

P.S.: I started a blog to report my progress and release documents and code. If you're interested, have a look! (http://garcimore1.free.fr/wordpress/)
Title: Re: Polystyrene chassis
Post by: mackmelby on December 17, 2008, 06:34:16 PM
Yea, that is a pretty common chassis layout. I currently own that gearbox and ball caster. But if you are wanting your bot to be more statically stable, you will need two ball casters. And your batteries should be mounted as low as possible. Also, those motors are weak. You might want to consider the performance motors from tammia. Just a little suggestion. :) Anyway, make sure you have the electronics to drive those motors too. you will need an H-bridge or a speed controller.