Hardware
Let’s list all the things we’re going to need to make a functional mock up of the Motion Tracker.
1.
A Raspberry Pi (Obviously) Please note that in the following setup I am using a Model B Pi.
2.
A Battery pack
3.
A Portable Display
4.
A Digital Compass
Note: The release of the Pi Zero is probably a better bet as it will fit more easily inside the case. Unfortunately I’ve not
yet been able to get my hands on one to test.
The Battery
The battery is probably the easiest thing to get. We are going to use it to power both the Pi and the portable display.
I have found that the best option is a Lithium Ion battery pack that is designed to charge mobile phones.
I picked one on sale from Maplins for about £15. It’s a 5,000 mAh pack with two USB outputs so it’s perfect for powering
two separate devices. Just remember that you will need to buy something small enough to fit inside the tracker casing along with all
the other electrical gadgets.
A Portable Display
Our next item on the shopping list is a display. There are a couple of options you can use. The simplest and easiest is to get is a
dashboard mounted LCD Display. You can pick one of these up for about £10-£15 on eBay. They have the advantage of needing no
configuration to the Pi code to get it to work. The disadvantages are that they will need to be modified to run on the 5v supplied by
your battery. This involves some finicky soldering and removnig of key components from the circuit board. Also they are pretty bulky
and may not fit inside the Hama slide viewer that the prop uses as a display case.
The better option is a small LCD display circuit board such as the ILI9341 based boards. These are usually small enough to fit almost
perfectly into the slide viewer and will run off the GPIO outputs of the Pi. This is the method I eventually elected to use.
A Digital Compass
The digital compass is used to move the backdrop of the display as you turn the tracker around. It creates a cool authentic look
to the whole setup.
Connecting and Testing
Reading and Calibrating
