Snap4Arduino is a Snap! extension. A full Snap! implementation that can interact with the physical world, through many types of electronic devices, especially those compatible with Arduino.
Snap! is a broadly inviting programming language for kids and adults that's also a platform for serious study of computer science. It is inspired by Scratch, written by Jens Mönig and Brian Harvey and presented by the University of California at Berkeley.
Snap4Arduino requiere boards with Firmata firmware installed. Check devices section.
Just download, unpack/unzpip and click Snap4Arduino.
Choose your system: Windows 64 (or its portable option), GNU/Linux 64, MacOSX, Windows32 (or its portable) or GNU/Linux 32.
Install Snap4Arduino connector and then, just play Snap4Arduino online (you can install it as an app from the browser to run it offline).
Chromium/Chrome/Edge browsers are required
Download Snap4Arduino connector, unzip its crx folder, type
chrome://extensions, select Developer mode and Upload an unpacked extension selecting that crx file (or just drag and drop it).
Just play Snap4Arduino online (you can install it as an app from the browser to run it offline).
Plugin for Chromebooks (chrome web store)
Chrome/Chromium/Edge plugin (download extension)
Current version is 8.1.0 (released on 08/01/2023)
You can also find older releases and unmaintained versions
Snap4Arduino requires boards with Firmata firmware uploaded.
You can upload Firmata firmwares direcly from Snap4Arduino (with both desktop and online versions) to UNOs compatible boards. Or just here:
A lot of devices support Standard Firmata. Tested on Nano, Mega, Leonardo and Micro.
Many 32 bit devices support Firmata. Tested on Due, 101, ESP8266 and NodeMCU.
Standard Firmata is directly uploadable with any Arduino IDE.
Other options are: SA5Firmata, Creative Robotix Firmata, MC Firmata Collection, Robotics-unleashed, Snap4ArduinoDev, LCD Firmata and Ultrasound Firmata
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.
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!
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.
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.
These public messages must begin with the + character. The rest of the messages are treated as private and thus are not accessible from the network.
Point your browser to http://IP:42001/vars-update=VARIABLE-NAME=VARIABLE-VALUE
This will set the global variable called VARIABLE-NAME to the value VARIABLE-VALUE.
This only works for global variables that start with the + character. Any other variables are not editable. Bear in mind that variables with names containing the '=' character can not be used, even though Snap! supports them.
You can also update multiple variables at once by means of a POST request (see below).
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, as long as the message starts with the + character (other messages are private).
Point your browser to http://IP:42001/send-vars
This will show a list of all global variables defined in Snap4Arduino whose name starts with the + or with the - character (variables starting with + are editable, while variables starting with - are only readable), along with their current value.
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. The variable must start with the + or - character to be accessible from the network.
Point your browser to http://IP:42001/stage
This will render a real time version of what's going on in the stage, like shown in this video.
You will be presented with an auto-refreshing HTML page, enabling you to watch the stage contents in your browser, though in a non-interactive way. You need to enable Public Stage from the settings menu for this to work. Otherwise, the stage is not accessible from the network.
Point your browser to http://IP:42001/stageimg
This will render a snapshot of the Snap4Arduino stage in the form of an image encoded in base64 that you can use for any purpose. You need to enable Public Stage from the settings menu for this to work. Otherwise, the stage is not accessible from the network.
<form action="http://IP:42001" method="post">
You can update multiple global variables in your project at the same time by means of an HTML form sent through a POST request.
By using <INPUT> and <TEXTAREA> tags, you can send all kinds of input types to Snap!, except for booleans. Their name attribute should contain the name of the variable you wish to update.
Note that Snap4Arduino expects all queries to be UTF-8 encoded. To make sure your query goes through properly, especially when dealing with special characters, you can always use:
<form action="http://IP:42001" method="post" accept-charset="utf-8">