See below for a list of suppliers and learning resources. Anything missing? These lists are maintained on Github where anyone can add or edit this list – see contributing for more information.

Suppliers

Electronics

Supplier More information Ships Internationally
http://www.sparkfun.com/ US-based Yes
https://www.adafruit.com/ US-based Yes
https://littlebirdelectronics.com.au/ Australia-based No
http://www.ebay.com/ Worldwide Depends on seller
https://thepihut.com/ UK-based Yes
https://shop.pimoroni.com/ UK-based Yes
https://www.modmypi.com/ UK-based Yes

3D Printing

Supplier More information Ships Internationally
http://3d-print.com.au Based in New Zealand No - only Australia and New Zealand
https://i.materialise.com/ US-based Yes
https://www.sculpteo.com/en/ US-based Yes
https://www.ponoko.com/ US-based Yes

Learning

Electronics

Resource Description
https://www.raspberrypi.org/ From the creators of the Raspberry Pi, lots of information and links to various resources, communities, D etc.
https://www.arduino.cc/ Homepage for the Arduino micro-controller with lots of learning resources and information.
https://learn.sparkfun.com/tutorials Sparkfun are an online electronics supplier but they also provide excellent tutorials on all things electronics from the basics (circuits, soldering etc) up to robot building.
https://learn.adafruit.com/ Another electronics supplier that provide excellent tutorials on a range of electronics topics.
https://learn.pimoroni.com/ And another
https://www.speedwaymotors.com/Info/All-About-Electronic-Circuits-for-Kids Electronics resources with a focus on kids (thank you Eliza from Lyndhurst STEM Club for Girls in New Jersey)

3D printing

Resource Description
https://www.tinkercad.com/learn/ Tinkercad is a wonderfully simply and easy to use online CAD editor that you can use to create 3D models for printing. They have a stack of short tutorials that help you to quickly get up to speed using their webware.
http://www.autodesk.com/ Tinkercad was created by a company called Autodesk who also provide excellent desktop CAD software. There's much more of a learning curve here than tinkercad so if you're new to 3D modelling stick with Tinkercad.
http://www.sketchup.com/ SketchUp is another good CAD program, but again there's quite a learning curve you've got to get through before diving into anything too complex.

Plant Physiology

Resource Description
http://prometheuswiki.publish.csiro.au/ Great online resource for protocols in measuring a range of plant ecophysiology

Contribute

Help improve these resources by contributing to the project.

Contributing

Integrating image capture and processing with 3rd party processes (or… how to build your own Caviconsole GUI!)

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Acacia dealbata
Stem xylem conduits embolising in Acacia dealbata. Comparison of original, difference and processed stacks. Captured using the new hand-lens clamp.