Arduino goes lambda!

What is it?

Snap4Arduino is a modification of the Snap! visual programming language that lets you seamlessly interact with almost all versions of the Arduino board.

You can see a short example of what you can do with it in the video at the rightmost column.

Snap!

Snap! (formerly BYOB) is an extended reimplementation of Scratch that allows you to Build Your Own Blocks™. It also features first class heterogeneous lists, first class procedures, and continuations. These added capabilities make it suitable for a serious introduction to computer science for high school or college students.

Snap! is presented by the University of California at Berkeley. It was developed by Jens Mönig, with design input and documentation by Brian Harvey and contributions by students at Berkeley and elsewhere.


Features

  • Blocks-based, dynamic, live, concurrent, parallel programming
  • Almost all Arduino boards supported
  • Uses standard Firmata firmware
  • Auto-configurable pinouts and high level hardware abstractions
  • You can interact with multiple boards at the same time
  • Desktop-based versions for the three major OSes
  • Free software licensed under the Affero GPLv3
  • Transpilation of simple scripts into Arduino sketches
  • HTTP protocol for remote control and live-streaming of the Snap! stage
  • Command line version for embedded GNU/Linuxes
  • Support for the Linino library instead of Firmata in new generation boards like the Tian, Yun or similar

Download

There are currently versions for GNU/Linux (both desktop and embedded), MacOSX, Microsoft Windows and Chromebook available, plus experimental versions for Android tablets and the web.

The project and all its components (including Snap!) are registered under public free software licenses (AGPLv3 and MIT), so you can download the sources and pretty much do whatever you want with them!

Please download the version that matches your operating system. Current version: 1.2.3, released on 28/04/2016

Installation

Snap4Arduino requires that you have StandardFirmata installed in your board.

To do so, follow these simple steps:

  1. If you haven't already, download and install the Arduino environment by following the instructions on http://arduino.cc/en/Main/Software.
  2. Open the Arduino IDE, go to File → Examples → Firmata → StandardFirmata
  3. Connect your board to a USB port in your computer
  4. In the Tools menu, select the board version and the serial port where the board is connected
  5. Go to File and click on Upload
  6. Snap4Arduino will now be able to interact with your board.

GNU/Linux

You just need to unpack the package. In most window environments you can just click on Snap4Arduino. If this fails, you can always run ./run from the command line.

MacOS X

Unzip the package and run the Snap4Arduino package. If you wish, you can move it to your Applications folder so you can access it as a regular app.

Microsoft Windows

Just unzip the package and run the installer.

ChromeOS

Grab it from the Chrome Web Store. If you want to use it in a device that's not a Chromebook, please download the CRX file and drop it in the

chrome://apps
tab of your Chrome or Chromium browser.

Embedded

The embedded command line version works in any GNU/Linux based machine, including embedded platforms and single board computers. New generation Arduino boards like Yun, Tian or Industrial 101 can run this version right inside the board, and if you have a regular Arduino and any kind of Gnu/Linux based single board computer, you can always have the latter be the host computer to the Arduino board, giving autonomy to your project without having to modify your Snap4Arduino program at all.

Check out this section of our GitHub wiki.

Android Tablets (EXPERIMENTAL!)

Make sure you have enabled permission to install from unknown sources, then just download the APK using your mobile device and install it regularly. This version is designed for Android tablets and will not be usable at all on mobile phones.

You will need a serial over Bluetooth connection for your board, please follow the instructions in the Bluetooth section of the wiki to set it up.

As it is still very experimental, please help us by reporting any bugs you may find.

Web based version (EXPERIMENTAL!)

If you just want to use it, follow the instructions in the Plugin section. To install it in a server of yours, unzip the package and serve the contents of the www folder.

Happy prototyping!

Demos

Here's a couple of fun things that can be done with Snap4Arduino, most of them recorded on a Hi-Tech last generation potato camera.

A bluetooth-controlled car (HOWTO: Blueetooth connectivity)
A line follower with parking lights
An ultrasound ruler
An LCD screen
A command line application (HOWTO: Command Line)
A somewhat autonomous RaspberryPi powered bullseye contraption (HOWTO: Command Line)
An Etch-A-Sketch that streams itself to any device over the network (source)
A shy Poppy Ergo Jr Robot
Music for a horror film of the 50s (source)
A machine that beats you at Tic-Tac-Toe
A mechatronic teddy bear
A LOGO-turtle-like bluetooth drawing robot (HOWTO: Blueetooth connectivity)
A mechatronic eye (source)
A Phiro robot (source)
Two laptops communicating via Morse

Source Code

You can find our GitHub repo at Snap4Arduino@GitHub. Please feel free to send us your pull requests and participate in reporting, fixing or commenting on bugs!

Supported Devices

You can modify Firmata to have it work with a wide variety of devices that, by default, are not supported. Check out this blog post if you want to do it yourself. Additionally, we will be publishing a series of modified Firmata versions and their corresponding Snap4Arduino block libraries here, so if your device shows up under this list you can just download the extension and start prototyping:

User-contributed Firmata versions

  • Edutec's Snap4ArduinoDev is a super-Firmata modification that allows you to use DHT11 temperature and humidity sensors, capacitive sensors, and stepper motors.
  • Joan Guillén's SA5Firmata is another super-Firmata modification that adds tone, pulse and ping functions, along with support for DHT11 humidity and temperature sensors, ultrasound sensors, Nunchuks and message sending and receiving over IR.
  • Matthew Canham's Snap4Arduino Firmata Collection features several great Firmata modifications.
  • Chris Clay's Robotics-unleashed is yet another super-Firmata modification that allows you to control several devices at the same time.

HTTP Protocol

Snap4Arduino comes with a built-in tiny HTTP server that mimics (and extends) the one Scratch 1.4 had. This means you can control your Snap4Arduino application from any computer, mobile phone, tablet or any other network-enabled device in the same network. In the following sections, the word IP refers to the IP address of the machine that has Snap4Arduino running on it.

Giving orders to Snap4Arduino

Point your browser to http://IP:42001/broadcast=MESSAGE

This will broadcast the message MESSAGE to Snap4Arduino, where you can capture it with a regular When I receive [message] block.

Updating the value of a Snap4Arduino variable

Point your browser to http://IP:42001/vars-update=VARIABLE-NAME=VARIABLE-VALUE

This will set the variable called VARIABLE-NAME to the value VARIABLE-VALUE. You can also send a POST request to Snap4Arduino to update a variable.

Finding out which messages is Snap4Arduino listening for

Point your browser to http://IP:42001/send-messages

This will show a list of all message names for which Snap4Arduino has When I receive [message] hat blocks.

Getting variables and their values from Snap4Arduino

Point your browser to http://IP:42001/send-vars

This will show a list of all variables defined in Snap4Arduino, along with their current value.

Getting the value of a single variables from Snap4Arduino

Point your browser to http://IP:42001/send-var=VARIABLE-NAME

This will return the value of the variable ready for you to use, no string manipulation needed.

Getting a real-time stream of the stage in Snap4Arduino

Point your browser to http://IP:42001/stage

This will render a real time version of what's going on in the stage. Like demonstrated in this video.

Web-based version (EXPERIMENTAL)

A web-based version is currently in the works. As with the desktop version, you need to have Firmata loaded into your board.

You will need to install a Chrome companion extension, that you can download here. Please note that you cannot install it straight from the downloaded file icon. Instead you need to:

  • Go to chrome://extensions in your Chrome browser
  • Drag and drop the Snap4Arduino.crx extension file into your browser window

When you are done, you can test it out live here.


If you prefer to run it in your own server, use this downloadable version.