Going to build a line follower need some help

[maitkaa]

Hey

So i am going to build a line follower for a competition and i would like some help. Will such motors be good : 6-14V d=27.5mm 11500rpm (costs 3.6€). And i will use this sensor : http://www.pololu.com/catalog/product/961 . The measurements are 25x25x25 CM and the weight limit is 1kg .For disain i thought it could be a dragster . So can anyone give me some tips and should i add transistors to motors or what materials should i use to build the body.

[waltr]

Are you thinking of putting wheels directly on those motors? How fast would it go when the motor a turning at 11500rpm? (this is simple math)

What is the torque? I'll bet it is too low to move your bot.
What you should look for is a Gear motor (see Pololu's motors).

The Pololu sensor should work.

A tip:
Look at the Top Right corner on this page. Then click on "Robot Tutorials" and start reading.
Many answers are there.

[maitkaa]

thanks for the tips

I found a new motor and the current idea is to use it to power the rear wheels with a gear system and use a servo in front to turn . What to you think of that ? Gonna check out the robot tutorial section now.

[newInRobotics]

Will such motors be good : 6-14V [...]

Your motor will work at highest efficiency at 14V, having that said, 14V battery will either be very expensive, or very heavy. My advice is to go with lower voltage motors.

Will such motors be good : [...] d=27.5mm [...]

Is it diameter of the motor or the wheel?

Will such motors be good : [...] 11500rpm [...]

High RPM indicates absence of gearbox, without gearbox Your bot will not be able to move. You need geared motor with lower RPM and higher torque.

The measurements are 25x25x25 CM and the weight limit is 1kg .For disain i thought it could be a dragster .

I've never seen a dragster of a shape of cube Also, better go for cube shape, as it will be much easier to make.

So can anyone give me some tips and should i add transistors to motors [...]

Where of the motor would You add a transistor? And why?

[...] or what materials should i use to build the body.

Use material that You find easy to work with, as simple as that. MDF, cardboard and Styrofoam are all good options. Also, take a look at Materials area of this website.

I found a new motor and the current idea is to use it to power the rear wheels with a gear system and use a servo in front to turn . What to you think of that ?

Very bad idea. Ackerman steering, as opposed to differential steering is very difficult to implement. My advice is to go for 2 powered front wheels and caster at the back.

[maitkaa]

i am not making a cube dragster the max measurements are 25x25x25 cm and the servo in front is a bad idea ? and a caster is just a wheel that can freely move ? Could i reverse your advice and but a caster in front and 2 rear motors ?

THank you for your advice

[newInRobotics]

[...] the servo in front is a bad idea ?

It's not a bad idea if done correctly and if You use stepper motor instead of servo. Servos are not able of continuous hold, hence if under load, they will jitter at 50hz while updating their angle. It's a smaller problem if You use digital servos, but still a problem. Jittering of steering system is the last thing You want in a line follower, as it will make line following difficult.

and a caster is just a wheel that can freely move ?

Yes.

Could i reverse your advice and but a caster in front and 2 rear motors ?

If You want to.

If I was to build line follower, mine would look something like CAD attached (it requires Autodesk Inventor (it's available free of charge for students)).

[maitkaa]

thnx will check it out . Will use a stepper and try .

[newInRobotics]

Will use a stepper and try .

What I'm saying is, differential steering and line following is simpler to implement than what You want to do.

[maitkaa]

a little update will use 2 motors and a wheel that can move freely going the simple way.