Pi WAAAAAAAAARS!

Well, I think I can be forgiven for the title, hey – I’m a little excited, ok?

The last competition was undoubtedly one of the highlights of 2015 and indeed of my Raspberry Pi experiences (and I have a fair few of those now!) So I was thrilled when in October (REALLY?!) I, along with the other teams, received the email from Mike and Tim telling us we had been successful and had been selected to take part in the 2017 competition. There were many more applicants than places so I am extremely pleased to have got in. However, the next week or so were taken up writing a PhD. proposal and in the latter part of October I found I had been successful. I was not due to start until February but my supervisor wanted me to start ASAP so life sort of went out the window at that point. I am currently living away from home and am based in Milton Keynes from Monday to Friday. This has made planning and particularly building a bot more of a challenge than I had expected.

Last year my entry, sHazBot was built almost entirely from recycled junk – something I am very proud of. She came a respectable 4th overall and had the brazen cheek to walk (well, roll) off with first place in the obstacle course challenge. I was even lucky enough to have my wife capture it on film…

sHazBot certainly performed admirably but with significant short comings. Whilst the motors I chose were extremely torque-y they were also pretty snail like and the bot certainly was not going to be setting any speed records. The control system was also fairly rudimentary with simple on / off controls for the motors. This was ok for some events, but really not suited to the events where precise, directional, control was required.

I therefore came up with a hit-list of what I wanted to achieve this time round:

  • Faster. Much faster
  • Proportional Control
  • Encoders on wheels
  • Better chassis design
  • More aesthetic. (I came LAST for aesthetics last time round!)

From winner… to the bits box.

It happens to us all eventually. We go from the top of our game to the rest home in a far quicker time frame than we can possibly imagine…..

shazbot

In this case, most of the parts have been donated to other projects – including this one! I took the motors out and did some tests before deciding that I was going to invest in some new ones. I also wanted a better designed chassis – well, to be frank, one that had been designed at all would be a good start.

If you follow me on Twitter, you’ll be aware of my latest acquisition and new found inspiration, I finally sold off a lot of old gear and scraped the funds together to invest in a 3D Printer. And a damn fine one too. I have seen too many people spend too much time fixing, calibrating and building 3D printers. While I’ll concede that this is a fine way to learn, I wanted a 3D printer to actually print things. So, I did a lot of research, settled on the exact model I wanted and set up alerts on eBay and Gumtree. I only had to wait a week or two until what I wanted popped up at the right price so after a quick trip to Leicester I returned home the proud owner of a (wait for it..) Wanhao Duplicator D5S Mini.

IMG_4661

All I can say is very impressed indeed. The version I bought was a 2015 model which did not have a heated bed. The 2016 model does, which is kind of an admission that it needs one. It does. I experienced warping on large, square prints and tried pretty much every combination of glue / tape / spray etc and was still having problems. I therefore bought a third party heated bed which is considerably cheaper than the Wanhao version and have had perfect prints since. I’ve had enormous amounts of fun mucking around learned an awful lot and have printed many useless, and a few useful, things.

I really wanted to design the full chassis for the bot and 3D print it. I was much impressed by Tito, Hitchen Hackspace’s fully 3D printed bot from Pi Wars 2015. I’ve been teaching myself to use OpenSCAD¬†which is a language based 3D modelling application. Really powerful but simple to get started and to be able to do enough with easily.

This week I have been mostly designing motor mounts and brackets.

mount

 

I was very impressed that the printer managed to print the complete piece with no supports necessary. I’ve got loads more design work to do on the chassis, I’ve got the motors and control board / controller to sort out and that will then give me the basic bot to work up from. I’ve got most of the sensors I am planning to use but need to get the main bot functioning before I can start to add complexity.

Long way to go, and the weeks are flying by. Did I mention I’m moving house too between now and the event?

Next time……. Motor woes and tantrum throws!

Until then….

 

 

 

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