New to robotics, need structure

[Rebelgium]

Hell everybody!

I'm 18 and studying to get a bachelor in electronics - ICT. I have already completed 4 years of electronics courses in high school, so I'm not new to the electronics part of robots.
I've always been very interested in robots and stuff, I used to play with lego's alot, and I love(d) racing around with RC cars.

so now (exams are over, good results btw , and I have time) I'm ready to build my first real robots.
I've already built a bunch of electronics projects, and i wanted to go a new direction and not only focus an electronics anymore, but also on mechanics etc. And combine some of my passions into one!

Now my problem is I need a cheap structure to build my robots on. To hold my PCB's, batteries, motors, etc.
What is the best standard structure?
Is there some sort of universal building blocks set that can be used to construct legs, robot bases, ...
-I really want it to be cheap
-and to be compatible with alot of equipment to hold. (motors n stuff)
-easily adjustable
-sturdy ( not robotwars-sturdy, but fall-down-the-table-and-not-be-completely-destroyed-sturdy )
-suggestions ?


I have a bunch of lego technics lying around here, so I think that will do great. The problems:
-How to get the mechanical power from my motors to a lego wheel/axle ...
-How can I make the lego's hold my own batteries , motors, PCB's, ...........
-Others problems I haven't thought of?


I don't want to use lego NXT because it's kindof expensive, it limits me in my options to build anything I want, and I want to make and design my own PCB's and circuitry.
But I am thinking of buying some NXT motors on ebay or somewhere, and just use these motors. I can make those motors turn with my own circuitry too.
What do you think of this?


So, if you have an answer to any of my questions , or solutions you've chosen, or if you have a suggestion, or just want to say something , reply! 
tnx

[Brandon121233]

Check out my Instructable for building my robot Walbot http://www.instructables.com/id/EXDGV5CF36FEUOP/?ALLSTEPS it might give you some ideas of what to do.

[S. Karim]

I have a bunch of lego technics lying around here, so I think that will do great. The problems:
-How to get the mechanical power from my motors to a lego wheel/axle ...
-How can I make the lego's hold my own batteries , motors, PCB's, ...........
-Others problems I haven't thought of?


I don't want to use lego NXT because it's kindof expensive, it limits me in my options to build anything I want, I want to make and design my own PCB's and circuitry.
But I am thinking of buying some NXT motors on ebay or somewhere, and just use these motors. I can make those motors turn with my own circuitry too.
What do you think of this?

Have you heard of the $200 robot contest? I'm submitting 2-3 robots I've made purely out of legos and motors/servos/sensors laying around my house. I'm going to be teaching people with legos some neat tricks to get legos to work non-lego motors and some helpful things to remember on how to create motor mounts out of legos and how to line the motors up to axle holes and such. Im not sure what you mean by getting legos to hold batteries, but if you can elaborate I might include it in the tutorial. Any other questions would be appreciated on legos so I can add their answers on the tutorial.

And that is ... if enough people vote for me, which is the only way my tutorial will get up.

[Rebelgium]

Check out my Instructable for building my robot Walbot http://www.instructables.com/id/EXDGV5CF36FEUOP/?ALLSTEPS it might give you some ideas of what to do.

I must say that is a very nice instructable, it is one of the best executed (movies are well edited, text well written, good structure, ...) instructables i've read.
And more importantly, the wallbot is great. You can really see it isn't the first version of the wallbot.

I can see how you've solved the construction-of-robot issues, but it doesn't meet my requirements. Don't get me wrong though, the plexiglass way you used to construct your robot is ideal for the final and definitive construction of a robot.
But not for easily adjustable prototypes.

Tnx for the great instructable though, it was, and will be, helpfull.

Have you heard of the $200 robot contest?

No havent heard of that contest, but i'll surely look into it.

neat tricks to get legos to work non-lego motors and some helpful things to remember on how to create motor mounts out of legos and how to line the motors up to axle holes and such. Im not sure what you mean by getting legos to hold batteries, but if you can elaborate I might include it in the tutorial. Any other questions would be appreciated on legos so I can add their answers on the tutorial.

Yes those are the exact solutions i'm looking for (if I  decide to use lego's).
By holding batteries I mean holding a battery pack so it won't fall off. You could include this in your tutorial too, Just call it "how to hold items in their place".
These items can be anything non-lego you want: cameras, sensors, battery packs, ...

[S. Karim]

Yes those are the exact solutions i'm looking for (if I  decide to use lego's).
By holding batteries I mean holding a battery pack so it won't fall off. You could include this in your tutorial too, Just call it "how to hold items in their place".
These items can be anything non-lego you want: cameras, sensors, battery packs, ...

ah beautiful! ill teach how to make a universal mount for everything non lego then, its a neat little combo of legos that do the trick

[Rebelgium]

ah beautiful! ill teach how to make a universal mount for everything non lego then, its a neat little combo of legos that do the trick Wink

Yes, that and how to line the motors up to axle holes are probably the most important issues for lego users.
I can't wait 'till you write that tutorial.

[S. Karim]

Yes, that and how to line the motors up to axle holes are probably the most important issues for lego users.
I can't wait 'till you write that tutorial.

Actually many times I've figured out its best to not line the motors up to axle holes, but it depends on the situation. Im assuming you're trying to run the motors through axle holes to use as a drivetrain for the tires?

What kind of motors are you using exactly? I'm going to be showing how to make mounts for servos and motors that look like the standard servo:



However, it may be difficult to work with other shapes, as long as theres one or two flat surfaces in the motor it can be done, but the situation is different for all motors so hopefully i can teach you how to come up with a solution yourself.



notice these dont really have any flat surfaces, so its a bit harder to make a mount but still it can be done.

[Rebelgium]

Yes what I am trying to do is:
use any motor and servo I want,
and attach it to a lego axle.

And with that axle i can do what I want. (attach it to a wheel , ...)

I think if you can integrate that in your tutorial, that would be the biggest succes.

Actually many times I've figured out its best to not line the motors up to axle holes, but it depends on the situation.

I'm not sure what you mean with that.

[S. Karim]

Yes what I am trying to do is:
use any motor and servo I want,
and attach it to a lego axle.

And with that axle i can do what I want. (attach it to a wheel , ...)

I think if you can integrate that in your tutorial, that would be the biggest succes.

Actually many times I've figured out its best to not line the motors up to axle holes, but it depends on the situation.

I'm not sure what you mean with that.

Okay cool, Ill make sure to show all of this.

[Rebelgium]

And do you also have a trick to attach the cog wheel of the servo/motor to a lego axle?
I'd really love to have a solution for that now. 

[S. Karim]

Of course, its easy actually. You just need to first find a servo horn that stretches across the diameter of the gear or something thats just long enough to have holes line up to the gear. Then, just get some screws long enough and screw it down. I have some rubber grommets between my screws to not damage the gear, which can all be purchased here:

http://www.servocity.com/html/servo_mounting_hardware.html

Servo and horn I used:



Gear I used:



Pics:





Other horns that will work:



You know, just improvise. Look through the holes of the gear and see which ones line up with the servo horn. Also, the gear I used has a + in the middle of it Im sure as you know, which is a 1 lego unit axle hole so from here, you can extend an axle out and put something on that axle, like a smaller gear or tire if you need to.