Thursday 10 December 2015

ElMo: post mortem

We did it!  PiWars took place almost a week ago and we had a blast!  A massive thank you to Mike and Tim for organising, to all the judges and jam makers, the sponsors, exhibitors, the show and tellers and the robot makers who all made the day so much fun.  It was brilliant to chat with other robot fans and makers - a great time was had by all in Team ElMo.  The day really seemed to fly by and the venue was always busy.  Matthew Manning has posted a great video of some of the action

Here is a link to some of the days photos and other video

And to a write up by Femi, a fantastic young blogger who featured on the raspberry pi blog

How did we do?  I am delighted that we finished in sixth place in the A4 and under category.  Congratulations to KEITH Evolution who won our category, and to Revenge of Pyrobot who won in the larger than A4 - both really impressive.  In fact well done to everyone - we all built robots, which is awesome!  We rarely scored  very highly in any given round, but must have been consistent overall.  Here are a few thoughts on how we fared and what we have learned from the day

Obstacle Course: 15th/27
The course was created with help from Piborg, and I thought we were due for an early bath when crashing over the very first hump killed the power to ElMo :(  Luckily the loose wire was soon back in place and given we had to wait to reboot before continuing, I think 15th was pretty good!
Learning:  make sure all your wiring is firmly connected!  Plenty of torque is required to get up the inclines.  A bit more speed might have helped us to avoid being crushed on the rotating platform.  Watching your robot being crushed is a horrific emotion!

Line Following: 9th/11
Thanks to cannybots for a fairly fiendish course - much more twisting than our home built test track.  We had to really slow down to get round and even then we came off a few times and had to rescue.  So a fairly low standing, but we got some points for having a go!
Learning:  I think a couple more IR sensors might have helped - I read a great piece on robotroom about a fast linefollower called Jet, which could follow a line at over a metre a second - something to aspire to next time.  One of the spectators suggested our sensors were a bit too far in front of our wheels, so we didn't turn quickly enough - we'll have to experiment with placement of the sensors.

Proximity Test:  10th/21
This one I thought we did OK - and I think we benefited from erring on the side of caution.  We stopped about 30-40mm from the wall each time.  But we spoke to a team that had a couple of runs with only millimetres of gap, but they incurred a 30cm penalty for touching the wall on their other run.  The winners were awesome - only a couple of mm from the wall on each attempt.  I'd like to find out how they managed that :)
Learning:  maybe we could have been a bit less cautious, but I'm happy we didn't hit the wall.  Check out other sensor options, ultrasonic is OK, but I think light/IR might be better?

Skittles:  10th/30
Again, we did OK - and might have done better if our code had not let us down on the day.  For some reason, the cannon failed to fire on our first couple of runs, so we got zero skittles.  We then resorted to firing the cannon from a stationary position and knocked over 12 or so from our next four attempts.  The guys with the flywheel were awesome and the winners got strikes and spares and scored around 40 points I think!
Learning:  Check your code thoroughly.  A few more volts might have given us even more va va voom.  I think robot football would be a challenging problem.

Straight Line Speed: 23rd/30
We're definitely not the quickest - even when we upped the voltage to the motors.  We must have been more that 20 seconds slower than the fastest team.  But I was pleased we were autonomous and we didn't hit the sides :)  The 12v motors supplied with the diddyborg metal edition meant it completed the course much more quickly than we did
Learning:   Faster motors would help here, but controlling something quick might be more difficult.  And you'd still need plenty of torque for other challenges.

Three Point Turn: 13th/22
We got the distances right after much calibration - but ElMo was somewhat prone to veering off at a jaunty angle, so we struggled to get back into the starting box.  Some of the other teams did very well - I think this challenge would benefit from a reliable compass or wheel encoders.  Or both.
Learning: more tech required to have a decent stab at this - relying on just timing is only going to get you so far

Code Quality:  15th/27
Mid table - I'm not sure what the judges were looking for. We used a lot of other peoples libraries, so we were perhaps less home rolled than some,  Our code is on bitbucket if you want to take a look.
Learning: check out the winners code and see how the professionals do it.

Build Quality:  21st/30
Not great - I assume we lost a few marks because we were mostly built from a kit.  And we did have a loose connection.  And the beautiful triangula was a very worthy winner here.
Learning:  we should get down to Makespace and learn how to use their laser cutter and build something more beautiful and bespoke next time.

Blog: 3rd/21
Our highest mark!  I hope one of two of you have enjoyed reading our exploits - it has been an interesting experience writing about the process
Learning:  keep writing!  Although a few weeks of peace might not go amiss

Aesthetic:  29th/30
Again, I hope that we were marked down because we came from a kit - although we did mill our own lid.  I thought the orange perspex was very fetching.  There were plenty of people who commented favourably on the ElMo theme during the day.  But next time we'll have to go more bespoke and add more bling.  Again, the beautiful triangula set the bar very high in this category
Learnings:  more lasers, more lights :)  Beauty is in the eye of the beholder.

PiNoon:  Round two (having got a bye through round one)
We didn't really stand a chance against the mighty triangula, who went on the win the PiNoon challenge.  It was a definite rabbit in the spotlights moment - mercifully swift!  I thought the pin and balloon idea was great fun, it didn't matter where you were in the venue, hearing the pop meant another competitor had bitten the dust.
Learning:  need to be more nimble - and maybe get a bit of luck in the draw as well :)

Right, that's probably the longest post of the PiWars season - well done if you've managed to read down to here and hopefully see you again next year.  We'll be the ones with bigger motors, more light, extra sensors, snazzier chassis, etc, etc - this robot building lark can become addictive :)