Snap! Unicorn HAT Integration

The Snap! Unicorn HAT Server allows Snap! blocks to manipulate a Unicorn HAT.

The Snap! blocks map to the Unicorn HAT API.

Example

Setup

The server runs on a Raspberry Pi with an installed Unicorn HAT.

A full install of the Unicorn HAT software will install python and the required python packages: Unicorn HAT package and flask. Answer y to all the prompts.

cd 
curl -sS https://get.pimoroni.com/unicornhat | bash

Verify that Unicorn HAT installation with:

$ cd ~/Pimoroni/unicornhat/examples/
$ sudo python ./simple.py

Install git with:

$ sudo apt-get install git

Install the server with:

$ mkdir ~/git
$ cd ~/git
$ git clone https://github.com/athenian-robotics/snap-unicorn-hat.git

The server can run with python or pypy. Install pypy and the required packages with:

$ sudo apt-get install pypy pypy-dev
$ curl https://bootstrap.pypa.io/get-pip.py | sudo pypy
$ sudo pypy -m pip install unicornhat flask

Usage

Execute the server using python with:

$ cd ~/git/snap-unicorn-hat
$ sudo python ./server.py

Execute the server using pypy with:

$ cd ~/git/snap-unicorn-hat
$ sudo pypy ./server.py

Snap! Blocks Installation

To install the Unicorn HAT blocks:

1. Download the Snap! block definitions to the computer running your browser. You can copy and paste the definitions into a local file using an editor or use wget:

wget https://raw.githubusercontent.com/athenian-robotics/snap-unicorn-hat/master/snap/UnicornHatBlocks.xml

2. Start Snap! in your browser

3. Click on the page icon in the upper left hand corner of the Snap! window (the icon to the left of the cloud icon) and then click on Import... and choose the UnicornHatBlocks.xml file created in step #1.

Notes

• Make sure that you can reach your Raspberry Pi from the machine running your browser using the ping command.

• Since block requires the Raspberry Pi hostname, it is best to create a variable and assign it the hostname and then use that variable reference in all your blocks accessing the Unicorn HAT.

• Pixel changes will not be seen until show is called.