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Topic: How to build the hardware for a robot or Project (Read 915 times) previous topic - next topic

tyler_newcomb

Hello all,

I am curious as to how one would go about actually MAKING something.

I don't have a 3D printer, so that really cuts down my possibilities quickly. I also suck with woodworking, metalworking, plasticworking, or anything else that needs to work together to be precise. I have seen openbeam, but this still just isn't enough to produce some projects that I want, such as robotic arm, a video camera motion control, or a sorting machine. What can I do? I also can't afford custom made parts or hiring anyone to produce things for me.
I am not extremely knowledgeable, but I am always willing to learn!

PaulS

Quote
What can I do?
Hire someone that doesn't suck at woodworking, metalworking, or plastic-working. Or, practice and get better at one or all of them.

keeper63

I also suck with woodworking, metalworking, plasticworking, or anything else that needs to work together to be precise.
All I can say here is that you better start learning about one or more of those skills; start with wood first, then move on to plastic - leave metal for last (aluminum is pretty easy to work with, if you aren't trying to weld it - steel is easy to work with, even welding - but is pretty heavy stuff).

Let's say you want to build a simple robot base, and you have a couple of gearmotors and wheels to start with. Well, once you get the wheels attached to the gearmotors, then you need a base. A simple plywood base would be perfect.

Get a piece of plywood (doesn't have to be very large - 24" x 24" is fine) - 1/4" or 3/8" thick - and draw a circle. Then use a coping saw or a jigsaw to cut the circle out (follow the line on the outside of the line - you can use sandpaper after to even things up).

Position your motors on the base, note where the wheels are, and mark things out - so that the wheels can fit - each wheel in it's own slot. You can position the wheel at the outside edge (tangential to the edge), or inset them back a couple of inches from the edge. You'll either mark for an indent, or a slot - but whichever, mark it out, drill a starting hole (if needed), and cut it out. Again, use sandpaper, a file or rasp, even a dremel tool - to even things up.

Then re-position the motors, and get some u-bolts that will fit around the body of the gearmotor - place them over the motor with it in position, and mark where the holes need to be - then drill them out. Then test-fit the motors and u-bolts.

On the front and back, mount a small caster - you may need some spacers (washers) to get the caster level with the drive wheels - if it isn't perfect, leave it short - too tall and the drive wheels will have problems.

Drill some other holes to bring the motor wires up (a hole in the center of the circle would be perfect). For the rest of the chassis, you could use a few pieces of threaded rod and more plywood circles to make a couple of extra levels. Or - get a trashcan or bucket, and flip it upside down and mount it to the plywood.

Indeed - when you are at a store (hardware or housewares, etc) - look at stuff with the "eye of a robot builder" - and you will find all kinds of things that can be made into a robot (or parts of a robot).

Finally - get a copy of the first or second edition of Gordon McComb's book "Robot Builder's Bonanza" (indeed, if you can get copies of all of the editions, it would be best - but the early editions are very nice because they detail some old-school style robot chassis made from wood, metal, and plastic - with the assumption that you are a fair newbie at such construction).

Honestly, you don't have to be particularly adept or accurate with your construction attempts the first go-around. I've seen some amazing little robots made from what was little more than trash bodged together using a hot-glue gun, tape, and rubber bands. A robot can be easily made from cardboard (indeed - there was a kickstarter not long back where a guy was trying to fund a kit for a large-scale cardboard robot arm - he didn't get his funding, but he open-sourced and gave away the plans anyhow - look it up).

Don't get hung up on your lack of skills, or thinking that things need to be "perfect". Most of the time, that is more of a hindrance than anything. Just grab some junk, and start hacking. Don't worry if it isn't pretty, or doesn't work right the first time - unless you engineer something to the n-th degree (and even then,  there's a good chance it won't work).
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

tyler_newcomb

All I can say here is that you better start learning about one or more of those skills; start with wood first, then move on to plastic - leave metal for last (aluminum is pretty easy to work with, if you aren't trying to weld it - steel is easy to work with, even welding - but is pretty heavy stuff).

Let's say you want to build a simple robot base, and you have a couple of gearmotors and wheels to start with. Well, once you get the wheels attached to the gearmotors, then you need a base. A simple plywood base would be perfect.

Get a piece of plywood (doesn't have to be very large - 24" x 24" is fine) - 1/4" or 3/8" thick - and draw a circle. Then use a coping saw or a jigsaw to cut the circle out (follow the line on the outside of the line - you can use sandpaper after to even things up).

Position your motors on the base, note where the wheels are, and mark things out - so that the wheels can fit - each wheel in it's own slot. You can position the wheel at the outside edge (tangential to the edge), or inset them back a couple of inches from the edge. You'll either mark for an indent, or a slot - but whichever, mark it out, drill a starting hole (if needed), and cut it out. Again, use sandpaper, a file or rasp, even a dremel tool - to even things up.

Then re-position the motors, and get some u-bolts that will fit around the body of the gearmotor - place them over the motor with it in position, and mark where the holes need to be - then drill them out. Then test-fit the motors and u-bolts.

On the front and back, mount a small caster - you may need some spacers (washers) to get the caster level with the drive wheels - if it isn't perfect, leave it short - too tall and the drive wheels will have problems.

Drill some other holes to bring the motor wires up (a hole in the center of the circle would be perfect). For the rest of the chassis, you could use a few pieces of threaded rod and more plywood circles to make a couple of extra levels. Or - get a trashcan or bucket, and flip it upside down and mount it to the plywood.

Indeed - when you are at a store (hardware or housewares, etc) - look at stuff with the "eye of a robot builder" - and you will find all kinds of things that can be made into a robot (or parts of a robot).

Finally - get a copy of the first or second edition of Gordon McComb's book "Robot Builder's Bonanza" (indeed, if you can get copies of all of the editions, it would be best - but the early editions are very nice because they detail some old-school style robot chassis made from wood, metal, and plastic - with the assumption that you are a fair newbie at such construction).

Honestly, you don't have to be particularly adept or accurate with your construction attempts the first go-around. I've seen some amazing little robots made from what was little more than trash bodged together using a hot-glue gun, tape, and rubber bands. A robot can be easily made from cardboard (indeed - there was a kickstarter not long back where a guy was trying to fund a kit for a large-scale cardboard robot arm - he didn't get his funding, but he open-sourced and gave away the plans anyhow - look it up).

Don't get hung up on your lack of skills, or thinking that things need to be "perfect". Most of the time, that is more of a hindrance than anything. Just grab some junk, and start hacking. Don't worry if it isn't pretty, or doesn't work right the first time - unless you engineer something to the n-th degree (and even then,  there's a good chance it won't work).
Thanks a ton! This is actually really helpful, and I'm gonna finally actually go for it. Thanks!
I am not extremely knowledgeable, but I am always willing to learn!

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