So where do we start our Wall-E build? I decided the best thing here would be to start at what I saw as the most complex part, the track system. Joining the Wall-E Builders club and watching a YouTube video from tested.com showed me that it was possible but most people took an off-the-shelf approach to the track system.

I looked hard that the track system in use by other builders and decided that I would have to engineer the tracks myself since every off-the-self system I found was too big for my Wall-E. I decided right at the start of the project to make a 1/2 size Wall-E not a full size version. This was done for two key reasons. The first being I dont have the storage or workshop space for a full size Wall-E but the main reason is that I would be 3D printing most of the parts and my printer is only capable of a 200x200mm build and therefore this limits the maximum size of any part I can make. Going 1/2 size makes sense for a lot of reasons but this means everything is smaller and will present some engineering challenges when it comes to actuators for other parts such as the head or arms.

Having decided to start on the tracks and not wishing to 'reinvent the wheel' I started to look over the internet for Wall-E source material......pictures, drawings, models, etc. I found the Wall-E builders club to have some nice resources that helped to scale my version correctly however my big break came when I found the complete CAD to the track system on Thingiverse.

http://www.thingiverse.com/thing:70606

Wall E Tracks

This was a great leap forward but not 100% what I needed. All credit and thanks for this great work must go to the author 'moving_to'. The files included were DWG (Autodesk) so directly importable into my preferred AutoDesk123D software (Free CAD design package @ http://www.123dapp.com/). Importing in the design allowed me to scale it to 50% and break it apart for alteration and printing. I said alteration because scaling everything by 50% meant the holes designed for shafts and bearings etc are also scaled by 50% are are no longer the right size for anything. The system has also been drawn with a specific motor in mind and this now has to be redesigned to suit a different size and style of motor.

I altered the shafts to use standard M6 shafts and threaded rods and matching 606zz bearings. I also broke all the parts out into separate CAD files so that managing the parts and STL files was easier. Most of the work is now done but I have not yet decided on the final motor for this system and ordered a couple of different options from a Chinese ebay seller.

6vGear motor6vGear motor 2

Both these are 6v motors but are two different sizes and torque rating so I will have to experiment and then decide on how to best use these in the final design. I also have decided to add wheel encoders to the design so that the control electronics can monitor the track movement. These are also on order from china.

encoders

Part 2 will cover the motor alterations and final CAD files for the tracks.