Reviving our Lego Mindstorms with Microbits

Using Microbit with Lego Mindstorms technic Lego in primary computing.

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Like many schools we have equipment that was bought, well used by a couple of teachers and then they left, the focus on the curriculum changed and the equipment began to languish unloved and gather dust in a corner. We have several sets of Amusement Park Lego Mindstorms For schools (RCX1.0 controller, set number 9725) that haven’t been out of the box in at least the last three years (though the dust on the top of the boxes suggested and the fact that the sets were first released in 1998 leads me to suspect it may have been much longer!). 


Whilst the Robolab software and the drivers can be made to work with Windows 10 (the original requirements were for Windows 95 – bless), I felt it was time to try something different. 

As part of a CAS cross-curricular project to use Microbits with our year 4 children, we are building lunchbox buggies. We have some kit to build buggies but in an effort to give as many children as possible a hands-on experience, whilst not spending any money, I turned to our old Lego kits. 

The Lego motors are more powerful than the hobby motors we used from our buggy kit, but I kept the power pack (4×1.5V AA batteries) and the motorboard the same and hoped for the best! 


I cut off one end of the Lego wire connectors, split and stripped back the wires and connected them to the motorboard. 



I built a very simple frame and balanced the board, Microbit and power pack on top and switched it on and to my delight it worked!


So we will be sacrificing a set of Lego connectors but gaining a new set of resources at no cost to make more buggies. This will also allow us to offer two different ways of building buggies. Whilst the Lego one is perhaps more familiar, building the frame will be more of a challenge than using the lunch box and there is more physical dexterity and care needed to attach the wires to the motors when not using the Lego connectors. 

So if you have some old technical Lego gathering dust dig it out and give it a go!

Micro:bit lunch box buggy

My first attempt at building a simple buggy controlled by a microbit.

Next term at Rushey Mead Primary, we are trialing the Primary CAS Hub Micro Bit Project.

Aim of the project

The DfE has identified a number of ‘opportunity areas’ DfE announcement areas where there is an opportunity to create more computing support for teachers in deprived areas. This project aims to create a programme of support for primary schools in those areas (or in other areas that are classed as being deprived) focusing on a cross-curricular scheme of work which embeds the development of pupil’s computational thinking skills and which uses the micro bit with the aim of enhancing learning and motivation in KS2 pupils.

The project aims to enable a CAS Hub to provide the teachers in the project schools with the resources, skills and knowledge to confidently teach their pupils using the scheme of work and to provide ongoing support in terms of evaluating the effectiveness of the teaching and learning and to produce a case study that exemplifies the impact of project. Hubs that are able to find 2 or 3 schools that are in deprived areas and who are willing to get involved in running this project will be entitled to a free class set of micro bits, as will their project schools. These Micro Bits have been kindly sponsored by the Micro Bit

The resource pack on the CAS teacher resources site (free sign up required) includes a cross-curricular SOW based on the Ted Hughes Iron Man novel and involves the pupils building their own Iron Man model (D&T) and a micro bit controlled buggy (CS) and using their creation to retell an aspect of the Iron Man story (IT).

Building the buggy

img_3523-1
Nic Hughes’ Crumble controlled lunch-box buggy
The heart of the project is to make some simple buggy robots controlled by a microbit. Inspired by Nic Hughes’  Crumble buggy that I built in his CAS Annual conference workshop in 2016, (full instructions on his workshop slides) shown on the right, I thought we could make something similar using a microbit to control the buggy.
Kitronik have very kindly got the project started by sending us enough kit to make 7 buggies and we will have microbits provided by the Microbit foundation. So it was my job in the holidays to check that this would actually work!

 

Building the buggy was straight forward, though I made a list of helpful tips to remind me of things I will need to sort when scaling this up at school with our children:

  1. We need a supply of wire to connect motors to motor board and a system to either pre-strip the wires for the children, or a handy teaching assistant dedicated to the job in class! Attaching the wires to the motors is fiddly and it may be easier to solder them on.
  2. When we punched holes in the lunch box, the instructions recommended using an electric drill, we thought a bradawl might work but it split the plastic, so resorted to hot wire instead. Again, this will need to be done ahead of time or supervised in the classroom.
  3. It took my husband quite a while to find an appropriate slot head screw driver with parallel sides and very narrow head (3 mm) that would fit the very small screws in the connectors that hold the wires from the motor and batter packs in place on the motor board. We will need a good supply of these in the classroom!
  4. Double-sided tape to stick the ball caster to the underside of the buggy worked really well.
  5. The lunch box itself needs to be big enough for the wheels to clear the rim of the box – ours *just* made it!

Coding the microbit

The next step was getting the motors working. With some help from the wonderful Lorraine Underwood who managed via twitter to point me in the right direction whilst marooned in her car with a sleeping toddler, I succeeded in getting both motors working so the buggy can move forward.

What had perplexed me initially was that the microbit looks to have 4 main pins (the large gold ‘holes’), however, there are in fact 16 pins that can be addressed and when the microbit is popped into the motor driver board it all looks a bit more complicated! Looking closely at the motor driver board, you can see that pins P12 and P8 control Motor 1 and P6 and P0 control Motor 2. I also needed to know the right block to use – under the ‘device’ or ‘pins’ blocks – ‘digital write (0,1)’.

This slideshow requires JavaScript.

Finally, on Lorraine’s recommendation (and to see if I could transfer what I’d learnt in one coding environment to another one), I wrote the code again in the JavaScript blocks  PXT editor.  My very simple code (shown right)

lunchbox code forward simple
link to the code
to make the buggy move forward simply gives power to the motors when the batter pack is turned on.

 

 

 

The next steps will be to make the buggy turn left or right and to add some degree of control over it, perhaps by using the buttons.