added link to extension tasks

README.md

@@ -50,3 +50,4 @@ This repository contains a range of resources to help you:
 1. Instruction showing how to set up your laptop to allow you to write software, compile it and flash it to the supplied microcontroller (`arduino_setup.md`).
 2. A list of hardware including sensors with links to online tutorials (`hardware.md`).
 3. Some useful code samples to get you started (`sample_code.md`).
+4. Extension tasks to take your project further (`extension.md`).

extension.md

@@ -9,10 +9,11 @@ There are a number of challenges you should consider:
 
 - How can you check that the sensor package is connected to the Internet?
 - Can the sensor package be powered by batteries?
-  - How long will this last?
+    - How long will this last?
 - Can the sensor package send its location with the data?
 - How will you protect the sensor package in situ? This could be by using a standard plastic box or your team could design and build a custom enclosure using one the the University 3D printers. There is a good list of 3D design software [here](https://all3dp.com/1/best-free-3d-printing-software-3d-printer-program/).
-  - How will you ensure all the sensors still work effectively?
+    - How will you ensure all the sensors still work effectively?
+- would it be useful to include a small screen to display critical information such as connectivity?
 
 ## Designing a PCB