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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!

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Pimoroni Rainbow HAT

Pimoroni Rainbow Hat

With the release of androidthings, Pimoroni really upped the HAT game, designing a board with a range of displays sensors and sound to utilise all the features of the androidthings package. This review will be specifically focusing on use with Raspbian.

So what is it?

The Rainbow Hat is a collection of components, forming a very busy HAT for the Raspberry Pi, released for the use of androidthings. It features 7 Multi-colour LED’s, four 14-segment alphanumeric displays, three capacitive touch buttons, a temperature and pressure sensor, piezo buzzer and handy breakout pins, making it very accessible for the use of jumper wires, extending the use of the hat.

At a Glance

Initially, it is very clear to see, the sheer number of components packed into such a tiny board. Both the front and rear of the board are full, really emphasising the range of abilities and features the HAT really has. The level of detail which has gone into the silkscreen of the board is amazing, with handy pinout’s and I2C addresses, as well as some nice graphics surrounding the 7 LED’s enabling the HAT to easily be used as a barometer. The seven LED’s are nicely placed in a rainbow shape, continuing with the weather style theme, which can easily be adapted to suit your needs on the board. One nicely thought feature is the centre point to the LED’s, making it easier to display graphs. This is something not a lot of other lighting boards incorporate, usually using an even number of LED’s, and making it hard to add a centre point to projects. The alphanumeric display is a little on the chunky side, making it a little bit harder to access the capacitive touch buttons for people with larger fingers, however this is something to be expected from such a compact board.

Pimoroni Rainbow HatPimoroni Rainbow Hat

Software & Support

Alike all Pimoroni products, the software and support is fantastic, with a simple one line installer or using there Pimoroni dashboard, a simple graphical interface to allow you to install both the libraries and examples making it much easier for beginners to get their hat up and running. The python Library is very simple, with relevant functions to enable you to easily control individual elements of the hat. This is all installed during the software install, so it really is a very quick process to install. Another amazing feature of this product is the Pimoroni support, with the Pimoroni forums offering assistance through members of the staff and community, as well as a dedicated email address for additional product support.

To Conclude

To conclude, I feel the rainbow hat is a great all round HAT, for all experience levels, offering a reasonably priced add on (just £24) with a range of functionality. I think this piece of hardware could be used for countless projects and I am looking forward to investigating the what androidthings has to offer!