Pi Wars 2019 Part 1 – Gathering Parts

After 3 years of applications, i was finally accepted into Pi Wars! This is something i have always wanted to do, so I am very grateful for the opportunity!

Who Am I?

My name is Alex (@ajalexsmith on twitter)  and i have been interested in the Raspberry Pi since around 2013, initially using a Pi at school and later getting my own. Before this, i didn’t have one bit of an interest in coding, but after becoming hooked, I later went on to completing an apprenticeship in Software Development and am now a Software developer at a local printing company, in which we manage all of our own internal systems developed in VB.net.

Whats happened in the first couple of weeks?

Initially the plan was to design the robot exactly before purchasing anything. Since then, i have realised just how hard it is to get a nice and exact datasheet with any relevant information, especially purchasing things from overseas! All to be expected with such smaller price tags than mainstream shops. Because of this, I decided to compile all of the components I will need, so I can easily measure components to fit them in. So far i have decided on the following:

Motors

Motors are something i find very hard, deciding if i want to go for all out speed, or settle for more in the middle grounds, with a slower speed, but higher torque. I would be putting it lightly if i said i wasn’t too sure what i was doing, but after some deliberation and research, id decided to go for a 80:1 gear ratio motor, with a load speed of 300rpm. This should hopefully be a nice middle ground, and enable me to be evenly placed throughout the challenges.

Control

My plan was to use a wireless Xbox controller. I use one regularly on both my PC and Xbox for gaming, so it seemed like a perfect match. After many hours and trouble shooting in-between waiting for items to arrive, I have since decided to part from this idea and move over to a PS3 DualShock 3 controller. I found the Xbox controller to be too unreliable, failing to connect sometimes on boot and button mappings being inconsistent due to firmware updates. As previously mentioned, I use Xbox controllers on a regular basis, so I’m worried that any firmware or kernel updates could cause unnecessary problems. Initial testing of the DS3 controller seems much better, so it looks to be a keeper!

To navigate through the software i’m going to build, I will be using the Pimoroni GFX Hat. This will using the capacitive touch buttons, I will be easily able to navigate through the different challenges and calibration/test scripts.

Motor Controller

The motors require 12v and a high current, so I needed to find quite a beefy controller. I’ve always been a massive fan of PiBorg, having used their PicoBorg Reverse for my only other (very unsuccessful) robotics project. Their community support and forums seem great, ideal if I run into many problems. Looking into their range of controllers, the best one for my needs seemed to be the ThunderBorg, accepting up to 34V at 5A. More than enough for my motors. Because i require 3 individually controllable motors and the board only accepts 2 Motors, I have had to order 2, to daisy chain. This will also leave a motor spare, ideal for the space invaders shooting challenge.

Powwwweeerrrrrr!

Being fairy new to this area, power was another thing that I’ve found difficult to get my head around. Luckily, with help from Tom (@approx_eng)’s great guide, and help from the PiWars Discord, I placed an order with HobbyKing for all the supplies i will need. I got the following:

  • 2 x Turnigy Nano-Tech 1000MAH 3s 40C Lipo’s
  • 1 x IMAX B6AC V2 Balance Charger
  • 1 x YEP 20A Selective coltage output
  • 5 x XT60 Connectors (enabling me to add the battery into my circuit)
  • 1 x LiPo charging bag
  • 1 x 2S – 8S voltage checker

If you’re interested, the article i followed was this!

Leave a Reply

Your email address will not be published. Required fields are marked *