SnapBOOST

This is a BOOST extension for Snap!

It is based on Connor Hudson (AKA technoboy10) snap-server.

I just converted it to python3 and added the BOOST methods from own library, pyb00st.

It still needs some cleaning and improvements but it already works on my Ubuntu laptop and my Raspbery Pi Zero W.

The idea is to use a Raspberry Pi with BLE (like the Raspberry Pi 3 or the Raspberry Pi Zero W, but any model with a USB BT 4.x BLE dongle will work) as a gateway between a browser (on Windows, OSX, Linux Android, iOS...) and a LEGO BOOST Move Hub.

Altough it uses my own python library, it can be easily adapted for any other python library, like pylgbst

For now, this extension only controls the motors by time and only read the internal tilt sensor and the Color/Dist sensor, will add the rest of the commands later.

Requirements

• python 3.x
• pyb00st

Installation:

Create a working directory on the Raspberry Pi, like 'snap-boost'.

Save the Snap! extension script ('snap-boost.py') inside this directory and give it execution permissions.

Save the XML with the block definitions ('snap-boost-blocks-v#.xml') to the computer/tablet/phone from where you will use a browser to run Snap!

Create a subdirectory named 'pyb00st'.

Download my pyb00st library Only 3 files are realy needed, they are inside 'pyb00st-master/pyb00st/':

• movehub.my
• constants.py
• __init__.py

Put those 3 files in the 'pyb00st' subdirectory of your working directory.

Usage:

The extension assumes a Color/Distance sensor connected to port C, you can change to port D by changing the variable 'colordist_port':

colordist_port = PORT_C

Start the extension:

./snap-boost.py

You'll get:

Snap! BOOST extension by JorgePe
Serving at port 8001
Go ahead and launch Snap!
<a>http://snap.berkeley.edu/snapsource/snap.html</a>
Then import the 'snap-boost-blocks-v#.xml' containing block definitions for motor and sensors.
System:  linux

On your browser, start the Snap! runtime and use the menu option 'Import...' and specify the XML file you saved before.

You will now have blocks for motors (under 'Motion' category) and sensors (under 'Sensing' category).

Available blocks

The XML file includes definitions of 2 Motion blocks and 3 Sensing blocks:

For each block you need to specify the IP Address of your Raspberry Pi to use it (you could define a variable and use it with every block). If you change the port (8001 by default) on the python code you should also specify it.

move1motor requires a motor (a, b, c or d), a time value (between 0 and 999 milliseconds) and a speed value (between -100% and 100%)

move2motors is simillar but doesn't require a motor (as it works only with A+B motors) and requires two speed values (one for motor A and the other for motor B)

read color returns one of these colors: 'BLACK', 'BLUE', 'GREEN', 'YELLOW', 'RED', 'WHITE'.

read distance returns a number between 0 and 10.

read tilt returns of these values: 'TILT_HORIZ', 'TILT_UP', 'TILT_DOWN', 'TILT_RIGHT', 'TILT_LEFT', 'TILT_INVERT'.

First Example

This example makes the two internal Interactive Motors turn for 0.25 seconds at full speed whenever the distance sensor detects something at less than '6' whatever-units-LEGO-uses.

On my Vernie, that makes it runaway for a bit.

Second Example

When this example is used with Vernie it explores the world, moving forward until it founds an obstacle, then it turns right and keeps doing that, designing a path on the screen:

Here a video showing Vernie controlled with this code: https://youtu.be/9VF77k3UVa4