A Classroom set of Raspberry Pi’s – part 1

I attended #Picademy North at Easter (2015).  I committed then to a post about a Raspberry Pi project which would be a viable method of using Raspberry Pi’s in the classroom – initially for a coding club and subsequently for KS3 lessons.  Six months later I have sources spreadsheet for all the components; completed my testing, and linked my updated KS3 scheme of learning.  Here are my Raspberry Pi setup notes too and Physical Computing Notes.

My aim is two stage –

1. Support my Digital Leaders with using Raspberry Pi’s with the Coding Club on Thursday lunchtimes
2. Integrate the use of a half class set (x16) of Raspberry Pi’s for KS3 class use.  I have worked out that this will be for 2 teaching units, one in Year 8 – using the Pibrella to model traffic lights using Scratch GPIO tied in with Flowol; and a Year 9 Control Project unit using Python, the RaspIO Protection board and the ModMyPi Raspberry Pi YouTube Workshop Kit (see bid).

In addition, the 16 Raspberry Pi’s need to be straightforward to use in class by pairs of students so that effective learning can happen every time.  So far I have see Raspberry Pi’s working as standalone hacking devices; managed by people who are already proficient with programming; and I have seen multiple examples of how Raspberry Pi’s do not function as required…

Overview

Overall, I plan to have 16 always-out-Raspberry Pi’s, that are lifted down from shelves above the PCs, switchable views using the KVM from the PC, and using either the Pibrella or electronics kit using the Raspio.  For details please see below.

1a = KVM
1b = KVM toggle switch
2 = HMDI convertor
3 = ModMyPi clear case
4 = 40 to 26 pin breakout cable – see below

Step 1 – Using the same Monitor, Keyboard, and Mouse
At #Picademy North, James (@jrobinson_uk) told me about KVM’s, so that you can share a Keyboard, VGA monitor and Mouse (hence KVM) with both a PC and a Raspberry Pi.   Simply click a button to switch between the PC and the Raspberry Pi.  See this video:

Step 2 – Robust Raspberry Pi including breakout cable

I think a robust box is vital for sustainability of Raspberry Pi’s and that includes protection from dust if, as I plan, they are out all of the time.  I have chosen the ModMyPi clear case (means students can still see inside although it it is not totally clear) and the SD Card Cover (which can only be released from inside the box and by releasing 4 long screws). The breakout cable fits through a gap in the side.

Step 3 – Appropriate boards (hats) and how to use them

Each ‘hat’ for the Raspberry Pi is designed to fit on the 40 pin socket (for B+ and 2 versions) but of course, this will not work if there is a cover on.  Therefore I have worked with Jacob and Dave at ModMyPi for a solution.  If you choose a straightforward 40 pin to 40 pin breakout cable, then, in my view, there are too many combinations for fitting a more common 26 pin hat such as the Pibrella.  And some combinations cause a short for the Raspberry Pi!  ModMyPi have therefore made me a 40 pin to 26 pin Male breakout cable.

This means that as long as a 26 pin hat is the right way round, there is only one seating position: –

*Update – November*
My Digital Leaders started using the Raspberry Pi with Pibrellas.  The Male socket at the end of the breakout cable actually has quite fragile pins and about 2mm of freedom either end.  This gives younger/less dextrous students plenty of leeway to push the pibrella in at an angle and bend the pins.  With the help of Jake at ModMyPi, my solution now has the 26 Pin GPIO Connector Header Extender.  I attach a pibrella fully onto the top; push the first spacer flush; smear evostick between the two spacers; wait 2-3 mins, then push the second spacer up. You can just see the smear of glue between them in the first picture:

The extender is very easy to fit to the breakout cable and gives a much easier push-on (and easy for getting off) connection for both the Pibrella and the Raspio.

The Raspio comes in two versions, both 26 pin.  Again, with the principle of looking after the equipment, I have chosen the Pro version.  This means that there is built in protection for the Raspberry Pi if a cable is inserted to cause a short.  As a bonus, the Raspio provides very clear labels.

I looked at Simon Monk’s circuit ideas but have decided on the Raspberry Pi for Beginners YouTube Channel Workshop Kit by Matt (with equipment from ModMyPi).  I have also adapted a plastic case to fit the breadboard and the Raspio.  Again, to keep things simple, I only soldered the sockets onto the Raspio, and therefore also include an extra 10 jumper wires.

This gives an electronics box which should be easy to use (and to check back in) when used for the Y9 projects.  The Y8 unit just requires a Pibrella for each Raspberry Pi, and I will keep these in a standard science storage container.

If security becomes an issue, I have a plan to drill through a corner of each of the Raspberry Pi cases and secure them to bolts on the wall using 2 mm wire cable.

Please let me know your thoughts via @gr8ict and twitter.

Update 1 – 1st October

KVM velocroed to side of computer. Raspberry Pi velcroed to wall with cable ties to keep cables tidy.  All set for using Dance mat at Open Evening.