Another year gone by....

So, after much messing around with a few ideas (which i'll go into later), I've finally got round to designing a few bits to make a build. Its only going to be simple 2 wheel drive, with lifting rear hitch, and electronics in place to control what ever i attach to the back.

Here's a few piccies - first two are the metal work that needs machining up, the second two are how the existing plastic will sit around it

First test run

Small update....  If this works then you should be able to see the first test run around the kitchen!!!

CAT Skid steer

Right Tyler, it's a been a year so about time for an update........

Well, that's not long enough!  I'm trying to start up again, but I've also done a bit on another little project:-

Behold - The Cat 'Skid' Steer.  It's called that because it skids to steer - it's a bit like a tank but with just wheels instead of tracks.  Any way, it looks like this:-

So, that's what I started with.  The idea is to make it radio controlled, including making the bucket go up and down, and also tip.

First up, I needed to take it all to bits......

A long time ago I spoke a bit about servos, and how they moved when you moved the sticks on the transmitter.  Normally they move a little bit and then stop.  However, you can modify them so they keep going round.  And round.  And round.   And round........   This means that I can get them to drive the wheels.  You can also join the connections up so they move at the same time.  So, the plan is to have two pairs, one pair on each side.  So, a bit of chopping, and one cut finger later, and I ended up with this:-

Now the trick is to put the wheels on.  To do this I made some little round bits that would screw on to the servos and the wheels.  This is my first try:-

Seemed ok until I put the wheel on!!!!

The wheels caught on the screws holding the servo's on, so I needed to make some more:-

Now, some of the holes needed 'tapping.'  This is where you make the same thread (or the spiral bit) in the part as is on the screw.  You use a special tool to do this after you've drilled a hole a little bit smaller than the screw is.  It looks a bit like a screw, but has some slots in so it actually cuts.  You can see one attached to the little handle in the picture below, and another one at the bottom of the picture:-

You can also see a wheel in the corner with the little bolts holding the black spacer to the wheel.  This is what the back of the wheel looks like with it fitted:-

Below is an old spacer and a new spacer fitted - you can now see that the wheel doesn't hit the screws on the one on the left:-

All I needed to do now is fit all the new spacers and wheels!!!

At the moment a battery and the radio stuff is just stuck on with masking tape.  I made a video of it driving, but my wifi's being rubbish so I can't upload it - I'll try and upload it to YouTube later and put a link up.

The next thing for me to do is to figure out and make all the brackets to control the arm and bucket - hopefully it will take less than a year this time :D

The Gearbox

Well, I didn't really have a clue where to start on this one - I wasn't sure whether I try and buy one or build my own.  As I didn't know how big they were either I decided just to buy one and have a look.  So, this arrived in the post one morning:-

And this is what all the bits to be put together looked like:-

You can see the motor in the bottom middle; the gearbox casing either side of the motor; a bag of nuts, bolts and screws; a box containing the white plastic gears; the two long bars are drive shafts the wheels will fit on - one of them is round and the other is shaped like a hexagon.

And within about 5 minutes you end up with this:-

Having built it I have learnt two things - it's too little and too rubbish to use!  Due to the way it's put together it won't last 2 minutes before it either strips a gear or splits apart.  Still, I had to start somewhere - now to start looking to making my own.....

CAD explanation

Part of this blog is to show stuff I do at work (mainly as I have a family opinion that I'm like Chandler from Friends and nobody knows what I actually do!). Some of the work I do is on a CAD system. CAD stands for Computer Aided Design - it's using a computer to make the object on the screen first to see how it goes together. Then from this you can make drawings to show how the parts are made. So, here's how the screen looks when I start:-

There are 3 squares you can see, these are the 3 planes you can draw on. Imagine you are sat at the table in the kitchen facing the door to the living room - you can either draw on the table top (1 plane), on the wall your looking at (1 plane), or on the wall to your left with the cooker on it (1 plane). The thing we will draw will be 3D, not just flat like a picture. I'm going to try and draw a wheel....

First I click on a plane and draw the outside shape of the wheel. The number tells the circle how big it needs to be in millimetres. The distance from one side of the circle to the other is called the diameter.  The distance from the middle of the circle to the outside is called the radius.

This shape is now only 2D - it goes up and down the screen and across the screen. To make it 3D we have to tell the computer how thick / deep it is.

We now have a basic wheel shape, so I can start cutting bits out the middle to make it look more like a tractor wheel. To do this I draw another circle the size I want to cut out the middle (this bit is called sketching) and then instead of putting material on I tell it to chop it out.

Once I've cut all the bits out the middle I can start to put some tread on the outside, once again by drawing a sketch of the outline, then telling the computer it make it 3D by adding material. Here's one set of treads.

Now, I could draw all the treads by themselves, but this would take ages. Instead I can tell the computer to copy the treads I've drawn and pattern them around the wheel. I tell it which bits to copy, where they need to be copied to and how many I want, then I end up with this.

All the little blue dotted lines you can see are all the edges on the other side of the wheel - if the wheel was made of glass so you could see through it these are what you would see.

Finally, the best bit - COLOURING IN!

If you look at all the pictures together you'll see on the left there's a box with lots of writing in that gets bigger as more information gets put on to the model.  Each thing I do get's recorded here (it's sometimes called the model tree) - so if I need to change anything I can just click on the one I want to change and edit it.

So, that's how to do a simple thing like a wheel.  In real life every part of the tractor would be modelled.  These would then be put together in small blocks called assemblies, then these assemblies would be put with other assemblies to make the whole tractor.  Then you can do some really clever stuff with it like this:-

Claas advert using CAD

Radio Control

Right then - the radio gear.  I've had this box lurking around for a few years, so decided it was about time I did something with it.  I need to modify it as at the moment it's only suitable for aircraft - you're not allowed to use it on the land/sea (I could be happily be driving around in the garden and accidentally crash someone's plane!)

Now I'll explain what all the bits do...

I think you already know what the transmitter does with all the knobs and switches, so I won't explain that to you.

The Receiver:-

This is what picks up the signals from the Transmitter - it receives them so they call in the Receiver.  I'll have to buy a different one of these as this one works at the frequency for aeroplanes.

The Servos:-

These are the bits that move when you wiggle the sticks on the Transmitter - you'll probably have heard them moving on your own Radio Controlled cars when you do the steering.  There's a little motor inside, and some gears, they move the white arms you can see in the picture.  There's two shown - the one at the top is the one that comes in the box shown further up, the second one is a mini one I've got lying around.  Generally, the bigger they are the stronger they are.  They'll be used for the steering and lifting ploughs and things on the back.

The Electronic Speed Controller (ESC):-

Two pictures, but they're the same thing.  This is what tells the motor to go, so it will control the speed the tractor goes along at.  It will also send the power to all the different bits of the tractor.  In the bottom picture you should be able to see all the connections; the two clear round connectors go to the motor; the white square plug connects to the battery; the small black plug on the right plugs into the receiver and sends power to the servos; and just behind that is a little on/off switch.

The Battery:-

This is a battery that I have lying around.  It has 7 'cells' in - each one of the cylinders you can see is a cell, and when they're put together they make up a battery.  This one is the wrong shape and size at the moment to fit in the tractor, so I'll have to chop it up and make it the right shape.

How the Radio Control works:

So, I'll explain to you how the radio control bit works.  You hold the transmitter and wiggle the sticks.  This transmits a radio signal to the receiver in the tractor.  The receiver has the servos and the Electronic Speed Controller plugged into it, so can control them.  If you've wiggled the steering stick it will tell the steering servo to move.  If you've wiggled the Forward - Reverse stick then it will tell the ESC to make the motor go round.

The Starting Model

Right this is the model I'm going to try and make radio controlled:

It's a Britains John Deere 6930.  It's one of their bigger models so I thought it would be easier to put all the radio equipment in (also, I know they do a radio controlled version already - but buying that would be cheating and I want to get it to do more!).  The tractor is 1:16 scale - this means that the real one is 16 times bigger.  If you lined 16 of these up they'd be the same length as the real one!

To give you an idea of how big this one is I've put it next to a 2litre drinks bottle:

The last 2 pictures show how the front suspension works - it's very simple as the front wheels are on a bar which hangs off the bottom of the front of the tractor, but I'll show that in more detail later.  You can also see the 'hitch' at the back - this is what all the attachments fix to.  The one already here is rubbish, and is something I'll have to completely make from scratch if I want to be able to operate it like the ones in the videos: