AverageBot Devblog 8 – Ready to Roll

AverageBot ReadyAverageBot is ready for action!

It’s one week to go to Pi Wars, and with AverageBot 98% complete, what better time to give a final update before the competition. To check back on the previous 7 devblogs, click here to go to my PiWars page.

Last week I had just one physical part of the build to complete, a bit of testing/tweaking of my code and of course the mighty task of packing for the day.

Let’s show you the latest…

Big Pusha – complete!

In my last update I showed you my partially complete skittles challenge attachment – the “BIG PUSHA” – including the panel I had designed as the pushing paddle.

I had the paddle laser cut this week at MakersCAFE, which means the attachment is now complete and working as designed, despite having no confidence that the servos would work together in harmony.

Big Pusha robot attachment

Batteries on top, servos underneath – this is one hefty attachment!

I do have to make sure the servo power is only turned on once my code is running, otherwise they seem to default to different positions that would either break the servos or snap the attachment.

Here’s a video I posted to Twitter of the attachment showing it in action:

The code that runs it is actually very simple, and I explain this in Devblog 6.

There’s a few ways you can control servos with the Raspberry Pi, and I’ve opted for the rough n’ ready GPIO PWM option that produces quite a lot of servo ‘twitching’. The paddle between the servos keeps them still, but I suppose that’s a bit like pinning down a large angry drunk man – something will have to give eventually!

Hopefully it’ll last the competition…

Robot atachment servos

The servos are locked in to the paddle

My only other concern is that I haven’t considered any kind of mechanism to hold the ball once it’s within the mouth of my attachment. My plan here is to move very slowly once I’ve caught the ball, to avoid any bouncing off.

Code testing & refinement

Whilst most of the functions of my robot have been tested many times before, there’s always that thought lingering at the back of your head that you should give everything a final try before packing up and leaving.

I still haven’t done this, having had a busy week at work and also building a Christmas present for one of my family out of an Arduino (more on that once they’ve received it, as they might be reading this!).

I’m going to do most of the testing this evening, which should mostly be SR-04 proximity tuning and checking my speed levels still make the robot run straight.


Just like a holiday abroad, I need to make sure I bring everything I need. With a 1.5+ hour journey to the competition, I can’t afford to leave anything behind. Also similar to a holiday – I still haven’t packed yet, leaving everything to the last minute!

I’ve been using Google Keep to keep a list of things I need to bring. Obvious items are things like my battery charger, a spare Pi, extra batteries, tools, my laptop, the remote control etc.

There are also a lot of less obvious items that are easy to overlook – screws for the different attachments, a soldering iron (you never know), wireless router, super glue, zip ties, blu tack, spare SD cards and more.

Maker drawer mess

My tidy maker drawer has been destroyed by all this robot preparation!

Luckily there will be a shops like the Pi Hut there as well, who should have decent stock of things like