This forum has a lot of topics, so I've tried to make a handy index. I hope you find it helpful!

UPDATE: http://scratchx.org/ has been released since this guide was written. ScratchX is the official way of using unofficial extensions.

This guide is mostly obsolete.

HTTP extensions should be considered experimental; the ST has not promised that they'll support them in the future. Writing new JS extensions is preferred.

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This post lists the different kinds of hardware you can connect to Scratch (or Snap!), and the software you need to install to make them work.

If I've missed anything or made a mistake, or you have any questions, post a reply!

Contents:

• Types of Software
  
• List of Hardware
  
• List of Services
  

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Types of Software

To connect hardware to Scratch, there are two kinds of software:

Extensions add extra blocks to the normal Scratch program that let you control hardware. Scratch interacts with the hardware through the extension program.

Mods are modified versions of the Scratch program, so they can have more drastic changes: such as compiling and downloading a Scratch program to a robot. But they may be incompatible with the normal Scratch program, and it may be difficult to switch between the mod and Scratch.

NB: Except for the officially-supported extensions (currently only the PicoBoard and Lego WeDo), neither projects including extensions nor projects made with mods may be shared on the Scratch website.

Extensions can be made in a few different ways:

Javascript Extensions [protocol]

Scratch 2.0's online editor supports extensions written in Javascript that can talk to USB devices. The two extensions made by the Scratch Team – PicoBoard and Lego WeDo – are Javascript extensions.

To use Javascript extensions, you first have to install the web browser plugin: scratch.mit.edu/scratchr2/…/download.html You only have to do this once, and then you can use all available Javascript extensions. (Notes: better with Firefox/Safari/Chrome. Reported not working on OS X < 10.7 Lion)

The PicoBoard and WeDo extensions can then be loaded by clicking “Add an Extension” under the “More Blocks” tab. Other experimental extensions can be loaded by shift-clicking the File menu and entering the URL of the Javascript file.

Scratch 2.0 extension support is currently in beta / experimental, so it may change in future and may not currently work properly.

HTTP Extensions [protocol]

Scratch 2.0's offline editor supports HTTP extensions. These require you to install a separate “helper app” program for each extension. The helper app lets Scratch talk to that particular piece of hardware.

Snap! has a very similar extension mechanism, so most HTTP extensions are designed to support both Scratch 2.0 and Snap!. Blockext is a work-in-progress Python library that does this, while also making it much easier to write extensions: blockext.org.

Scratch 2.0 extension support is currently in beta / experimental, so it may change in future and may not currently work properly.

Scratch 1.4 Sensors [protocol]

Scratch 1.4 has a much more limited extension mechanism, called “Remote Sensor Connections”. It doesn't allow adding extra blocks; extensions can only report sensor values. It also allows reading variable values and sharing broadcasts.

However, Scratch 1.4 does have built-in support for the PicoBoard and Lego WeDo without needing any additional software.

ScratchPy is a Python library that makes it much easier to connect to Scratch 1.4: pilliq/scratchpy. There are others listed on the Python wiki page.

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List of Hardware

PicoBoard (aka ScratchBoard) [description]

• Built-in to Scratch 1.4
  
• Built-in, Scratch 2.0 online editor: (forum post) [Javascript]
  
• Modified version by SCRAXE: (forum post) [Javascript]
  
• S2Bot by SCRAXE: picaxe.com/s2bot [HTTP]
  

Lego WeDo [description]

• Built-in to Scratch 1.4
  
• Modified version by abee for controlling two motors: (forum topic) [Scratch 1.4 Mod]
  
• Built-in, Scratch 2.0 online editor: (forum post) [Javascript]
  
• S2Bot by SCRAXE: picaxe.com/s2bot [HTTP]
  

Lego Mindstorms

• S2Bot by SCRAXE: picaxe.com/s2bot (Mindstorms NXT) [HTTP]
  
• Enchanting (Mindstorms RCX, Mindstorms NXT): enchanting.robotclub.ab.ca [Scratch 1.4 Mod]
  
• SILENT (Mindstorms NXT): sourceforge.net/…/silentprj (forum topic) [Scratch 1.4 Mod]
  
• by botkop (Mindstorms EV3): koen-dejonghe/ev3-scratch-helper-app (forum topic) [HTTP]
  
• Snap-NXT by technoboy10 (Mindstorms NXT): technoboy10/snap-nxt (forum post) [HTTP, Snap!-only]
  
• ScratchNXC, part of PyNXC: web.bryant.edu/~bblais/… (archived forum topic) [Scratch 1.4 Compiler]
  

Gamepad

• scratch-gamepad by bobbybee: github.com/bobbybee/scratch-gamepad (forum topic) [Javascript]
  

Kinect

• Kinect2Scratch by saorog: scratch.saorog.com [Scratch 1.4 Sensing]
  
• saorog is working on a Scratch 2.0 version: (forum topic)
  

Leap Motion

• LeapScratch by khanning (outdated?): khanning/LeapScratch (forum topic) [HTTP?]
  

Raspberry Pi GPIO

• ScratchGPIO5 by SimpleScratch: cymplecy.wordpress.com/scratchgpio (forum topic) [Scratch 1.4 Sensing]
  
• Remote GPIO control by procd: (forum post) [HTTP]
  
• Xi cross-platform interconnect by itchy20: MrYsLab/xi [Javascript] [Snap!]
  

Arduino

• s2a_fm by itchy20: MrYsLab/s2a_fm (forum topic) [HTTP]
  
• scratch4arduino by polpe: cbecc/scratch4arduino (forum post) [HTTP]
  
• instructables.com/id/Scratching-with-Arduino
  
• Xi cross-platform interconnect by itchy20: MrYsLab/xi [Javascript] [Snap!]
  

Compatible alternative — Shrimp: shrimping.it

littleBits

• by abee: (forum topic) [emulates PicoBoard or Lego WeDo]
  
• by khanning: khanning/scratch-littlebits-extension [Javascript]
  

Sphero

• S2Bot by SCRAXE: picaxe.com/s2bot [HTTP]
  
• scratch2sphero by jishiha: champierre/scratch2sphero (forum topic) [???]
  
• (alpha) sphero by technoboy10: technoboy10/sphero [HTTP, Snap!-only]
  

Hummingbird [website]

• hummingbirdkit.com/…/snap [HTTP]
  

Parallax S2

• ssquared by technoboy10: technoboy10/ssquared [HTTP, Snap!-only]
  

Wii Controllers

• wiisnap by technoboy10: technoboy10/wiisnap [HTTP, Snap!-only]
  
• iiConnect2Scratch by CreativeComputerLab: creativecomputerlab.com/iiConnect2Scratch.html (forum topic) [HTTP?]
  

MaKey MaKey [description]

• It acts as a regular keyboard (or mouse). You don't need software.
  (forum topic)
  

Compatible alternative — ShrimpKey: fse.link/fseshrimpkey

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List of Services

• ScratcherControl Android app by khanning: khanning.com/scratchercontrol (source) [HTTP? (outdated?) & Scratch 1.4 Sensing]
  

Minecraft Pi Edition [website]

• scratch2mcpi by jishiha: github.com/scratch2mcpi [Scratch 1.4 Sensing]
  

Language Translation

• Scratch Translation Extension by khanning: khanning/scratch-translate-extension [Javascript]
  

Speech Synthesis

• snap2speech by technoboy10: technoboy10/snap2speech [HTTP, Snap!-only]
  
• by procd: (forum topic) [HTTP]
  

Superb! Mods please sticky this.
Thanks for the hard work Blob8108.

P.S. Do you know if your offline editor fixes will be added to the official release? How do we use the swf file as replacement for the offline editor?

procd wrote:

P.S. Do you know if your offline editor fixes will be added to the official release?

I believe they will be, but not for at least several more days.

How do we use the swf file as replacement for the offline editor?

You could try dragging the file into your web browser, or using Adobe's standalone Flash Player. With varying degrees of success.

Can you add the Shrimp (http://shrimping.it) (Arduino Uno-derivative) and my ShrimpKey (http://fse.link/fseshrimpkey) (DIY MaKey MaKey) to the list?

sdmeijer wrote:

Can you add the Shrimp (http://shrimping.it) (Arduino Uno-derivative) and my ShrimpKey (http://fse.link/fseshrimpkey) (DIY MaKey MaKey) to the list?

Hmm. Are those just fully-compatible alternatives to the Arduino and MaKey MaKey, respectively? I could add them as links at the bottom of those sections.

Looks great! One thing not mentioned anywhere at all is that the official web browser plugin needs OS X 10.7 (Lion) or later to run, even though it will still happily install without warning on earlier versions (such as older 1Gb Macbooks which are stuck on 10.6.8). On Windows anything from XP up seems to work. And that you will probably be better off using Chrome / FireFox / Safari when trying to use the js extensions.

SCRAXE wrote:

One thing not mentioned anywhere […]

Added.

blob8108 wrote:

sdmeijer wrote:

Can you add the Shrimp (http://shrimping.it) (Arduino Uno-derivative) and my ShrimpKey (http://fse.link/fseshrimpkey) (DIY MaKey MaKey) to the list?

Hmm. Are those just fully-compatible alternatives to the Arduino and MaKey MaKey, respectively? I could add them as links at the bottom of those sections.

Yes, they are!

have anyone tried using S2Bot for Sphero before? my connection with the S2Bot show that it is connected however when i want to test it it doesnt seem to be moving anyone have any idea how to connect it?

When S2Bot is connected click the S2Bot ‘test’ button. You will then see 4 buttons that enable you to test the backlight, the LEDs and to rotate the sphero on the spot (the test buttons deliberately don't roll the sphero because that just generally results in it rapidly disappearing off under a table!).

The open the template .sb2 file in Scratch to use all commands (including movement).

Here's a sample Sphero project to move in a square.
http://www.picaxe.com/docs/sphero.png
Use a speed of 50-100 for nice slow movements
The red stop button above the Stage is your friend, as it will stop Sphero when it tries to escape!

SCRAXE: You should make a thread for S2Bot.

SCRAXE wrote:

When S2Bot is connected click the S2Bot ‘test’ button. You will then see 4 buttons that enable you to test the backlight, the LEDs and to rotate the sphero on the spot (the test buttons deliberately don't roll the sphero because that just generally results in it rapidly disappearing off under a table!).

The open the template .sb2 file in Scratch to use all commands (including movement).

when my S2Bot show connected my bluetooth setting still display sphero not connected. Could this be the reason why i am unable to connect to my sphero and not being able to get it moving?

Another one to add please. Topic here http://scratch.mit.edu/discuss/topic/34754/ It's an http extension for controlling a raspberry pi's gpio pins remotely.

Congrats on getting the first sticky in the connecting to the physical world forum!

The problem with Macintoshes® and some computers running Windows running newer versions of Java is annoying. When I tried to install Java on my Mac, it refused to install, but my computer continued to try to install it, I eventually had to restart (not because of that) and that took down the Java installer with it.
I later tried to install Java again with the same result, luckily I knew what to do that time. I have also had the same problem with Java on a PC.
(This is connected to the part about Java Script Extensions, see above)

Hi can you add Scratchbot(www.scratchbot.cc), it's a modified version based on the source code of scratch 2.0, it's much easier to use than other Arduino-Scratch connections, and it can support many types of sensors and motors. -

Does anyone know when the OFFLINE version of Scratch 2 will support WeDo and the pico board?

mrabourn wrote:

Does anyone know when the OFFLINE version of Scratch 2 will support WeDo and the pico board?

ST have been working recently on adding JS support into the offline version, so hopefully not too long to go now before native support of these parts.

However you can actually use both with Scratch offline already by using the S2Bot helper:
picaxe.com/S2Bot

@blob8108 - you may wish to update this section…

blob8108 wrote:

The current offline editor (v404) has the following bugs:…