DiY cheap robot from recycled parts

[franciscodr]

Is it possible for anyone to build a cheap yet scalable robot from recycled parts?

We saw here already many DiY robots from recycled parts, the cheap simple robots topic and the $10 robot contest from the African Robotics Network, all these work good both to learn and to check robotics.

But they are not very scalable (they can't grow): they are too simple to increase capabilities if we get new parts like more sensors, better controller board and so on to learn new things.

So the challenge is this: building a functional (and scalable) robot from recycled parts that anyone can find/have easy like:

• bottle taps
• motors from old printers
• parts from old toys: chasis, batteries...
• wood sticks from cheap shops
• hot glue
• rubber bands...

Please note: 3D printing or robot kits are not allowed in this "low cost" project, as many people don't have access to them.

Maybe the only thing we have to buy is the controller board, that with an Arduino is still quite cheap nowadays.

Progress:

20/May/2015

After a night dreaming about the tracking issue (see bellow), I found that direct motion between dc motor and wheel was compulsory.

So I attached each wheel to the motor with two plastic bottle caps and some hot glue (aligning all the parts was the crytical point here):

 

I had also to make a hole to fit the partially each motor, so the whole extructure was solid:

 

 

Here the hole for the second motor:

 

 

I also added a third wheel for turning easy that came from an old furiture:

 

 

And this is the chasis with motors right now. Both look and more important, running, are improved:

 

 

Above you can find the video (it is the second one) with the improved behaviour of the chasis with motors. Next step: adding electronic control to the motors.

 

19/May/2015

Details on the robot right now:

• Wheels made out of cardboard + bottle taps + wood sticks +`foam, all together with hot glue.
• Chasis and battery from old toy.
• DC Motors from old printers.

This is how far I got: robot moves but wheels run better in one way than the other one, due to poor coupling between motors and wheels. Note: I tried already coupling with rubber band from motor to wheel, but it didn't work at all: the robot was still, see picture with detail of the rubber band:

 

I found some useful DiY ways to link motors to wheels, but I didn't tested all of them yet... Here is the list right now:

Direct coupling from motor shaft to wheel (thanks Basile): (not good when you need good torque)

 

 

DiY gear "box": (good if you have already the gear wheels)

 

 

DiY coupling box with screw:

 

 

Standard coupling with screw (there are many variants around to buy):

 

 

And this is the traction part right now:

 

 

As you can see in the first video above, traction is not good enough for several reasons, mainly the wheel is not perfectly aligned also the connection between motor and wheel is not good enough. I'm planning a new coupling that means to change the whole arrangement of the motors. Let's see...

This is a work in progress so any suggestion is welcome. Thanks!

Moves around with its three wheels

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This is a companion discussion topic for the original entry at https://community.robotshop.com/robots/show/diy-cheap-robot-from-recycled-parts

[dannyv]

spring

You can try to push the motor onto the wheel, with a spring or rubber band. or by using it’s own weight. 

[franciscodr]

Good idea…

Hi Danny,

Yes it’s a good idea and I’m already planning it. However it can be tricky as the union between wheel and motor shaft should be good, otherwise there can be friction between both due to a missalignments.

I didn’t understand the spring idea, could you please explain it a bit more? Thanks!

[dannyv]

like this:

(Image comes from robotroom.com)

[franciscodr]

Great picture!

Ah ok Danny, now I see. I’m using now a similar approach, but instead of a spring I’m using a rubber on for the same purpose. I’ll publish a picture soon. Thanks for the detail.

[silux]

Arduino nano clone, L9110

Arduino nano clone, L9110 driver module, breadboard 400pt, male jumpers, HC-SR04, rechargeable batteries for 4.8 - 7.2v.

Plywood like assembled cardboard, wheels and motors hacked from an rc toy. Already done

[franciscodr]

Great ideas

Hi Silux,

Good and fast explanation! Could you please post here the link to that robot? Thanks!

I found an interesting link in one of your posts to a cheap robots that looks interesting However, my challenge is not only to do a cheap robot, but also a scalable one, so it has to be strong enough to keep growing to support a robotic arm, a camera and batteries to manage everything from arduino to raspberry pi boards…

[silux]

Then go for plywood

Then go for plywood cardboard. It does scale well but has problems of humidity and bulkiness; any plastic and aluminium is necessary if you want a bigger robot.

I’m experimenting with a 3d pen at the moment. With some copper wire i think i could support the whole robot. It can also join other pieces of plastic together:-)

[franciscodr]

Copper or steel wires for DiY

Yes Silux,

Your latest idea on copper wire reminds me my (very) old times when I studied my secondary school on electricity. First year we spend some weeks learning how to do soldering. Some practices were just soldering shapes and figures with just wires of copper. We strech copper (or steel) wires before so they get strong, and that was a trick I used later with steel wire, harder to do the trick but better for stronger elements. To strech the wire you can attach one end to something fixed (and strong) and pull the other end with pliers. If you don’t have a fix strong end, try to do by your own with two pliers: one fixed by one foot, the other with one hand. It’s harder but if you are strong enough (and the wire is not too thick) you’ll do it fine.

I tried to use this technique with a DiY robot some months ago, but I tried too hard integrating also gears, it didn’t work fine but I’ll go back one day:

 

 

(metal plate came from an old 2.5" floppy disc drive).

Please note: if you try just be careful to use a powerful soldering iron and avoid burning yourself as wires get hot to solder them properly ;-)

 

[silux]

like this:)

I do use proper protection (glasses, insulated tweezers, third hand).
Copper is just to make the battery holder and embed some electronic circuit directly on the body of the robot.

[franciscodr]

It looks good

Ok now I see it and it looks good. Thanks for sharing!