We're in ....

It's official - we've been called off the reserves bench to join the action and compete in Pi Wars 2019.

Now the pressure's on. No longer will the phrase 'Never mind - at least we're only a reserve!' be uttered in the Sputnik household. 

Not much notice for the competition - but we've been progressing well and at least we have a robot that is functional - and should be able to compete a fair few of the challenges as it stands. Two of us are off to Brian Corteil's Robot Club meetup at Cambridge Makerspace this Saturday to hopefully try out some of the challenges in a real environment. (One that doesn't involve cardboard boxes for obstacles.).

Things we've learned in the last couple of days:

- Being selected for Pi Wars with less than 2 months to go doesn't help you get a good night's sleep!

New Year, New Look

So much for doing lots of robot building over Christmas - there was just too many other things to do. But now it's January and things are getting back to normal. After making lots of progress at the beginning of December in getting the robot talking to the Arduino and using it's sensors for a straight line test, we realised it was time to rework the chassis to get everything fitting the way we want it to. Part of this was to put another layer to hide the wires and mount the BBC micro:bit.

Here is the result:

Sputnik side view

Sputnik Top View

How To Train Your Robot

Somehow we managed to miss a blog update in November - how time flies. 

November was all about software. The saws, screwdrivers, crimping tools and sellotape were put away, and out came the laptop. 

One of the aims of building this robot was for me to learn Python. After a couple of weeks, I was threatening to name this blog '10 things I hate about Python' but I persevered and am beginning to forgive it. 

I decided to keep it simple and implement a single, multi-threaded application, rather than trying to have multiple processes. I drew out a simple design - just to keep me on track using UMLet. This is the best free tool I've found for sketching out rough designs really quickly. This was just to give me a rough idea about the classes and what needs to know about what.. 

Initial Class Diagram

Tears, Cheers and Motor Gears

October has been a tough month for us. After rebuilding the robot in plywood (much easier to work with than acrylic) and putting in some motors with more torque, we were ready to test again.

The motors we tried were, again, micro metal motors from pimoroni - but 298:1 gear ratio instead of 50:1. It went forward - and backwards - but again, even with the extra torque refused to turn well. It was better - we could get it to turn if we put on some less grippy wheels - or were moving at the time. But not great. The large, soft, wide wheels we want to use (to give us some natural suspension over obstacles) just have too much grip. 

If at first you don't succeed ...

After days sawing, drilling, redrilling and redrilling (honestly - some parts are looking like a sieve!) some sheets of 3mm acrylic, and then bolting on all the motors and electronics, Sputnik 0.3 emerged.
The first robot free from lego.

With hope and suspense in the air, the Raspberry Pi (and currently unused Arduino) were powered up. The controller was paired and we were delighted to see the motors turned in the correct direction when we moved the controller without having to swap round all the wires. That has never happened before! Hopes were high.

Sad(ish) News

The days of waiting are over. No need to press refresh on the email app every 5 seconds. The email from Pi Wars has arrived.

Unfortunately Sputnik did not make the cut for Pi Wars 2019.

However, not all is bad. We did make the reserve list - so the build is still on!

Lots to do ....

CAD Phase Complete

Looking at some of the other Pi Wars competitor's blogs and seeing the wonderful designs rendered in CAD packages we thought we'd have a go ourselves. However after 5 minutes with FreeCAD it quickly became clear that the only thing we would have by March next year would be a design.