Box with a secret knock in it

In the second of my two interviews this week, I was invited by Whitmore Park Primary School in Coventry to help them look at ways to develop their children’s skills as active learners in mathematics.

With only a day and a half’s notice for the interview – which required me to design and deliver a ten minute activity with a group of pupils – the only sensible thing to do was not only to figure out the content of the activity, but also to embark on constructing a technological doohickie, the workings of which I had no prior experience in! Well, it’s all good learning, isn’t it?!

The things I wanted to achieve through the activity were:

  • To have the activity pupil-led as much as the restrictions in time would allow.
  • To use an approach that referenced my previous immersive experience projects and/or Mantle of the Expert, in order to provide a starting point for conversations regarding strategies of role play and active learning.
  • To use a medium that highlighted a ‘special’ technical skill that I could contribute to the mix – ie something not likely to already be available or in use within the school.
  • Something that felt to me like it was a genuine activity, and not too much like ‘maths dressed up’.
  • Something with a bit of ‘wow’ to it.

Riffing of something I had referenced in my application, I decided to do something based on code-breaking, but I wanted this to involve a physical object – one that would respond when the code had been broken. This, I felt, would give me a chance to make something using my hack/electronics skills which, whilst not being up to much in the grand scheme of things, should be adequate enough to impress a 9 year old…

After much searching of Instructables and Hackaday looking for the right combination of inspiration and cold, hard instruction, I decided to work with a system for recognising sequences of knocks in order to open a box. For this I am deeply indebted to Steve Hoefer’s detailed documentation of his Arduino-based Secret Knock Detecting Door Lock, which I only modified slightly to take into account the resources I had available.

Secret knock box gubbins: components labelled up to facilitate explaining what they were for, free ends of wires labelled up so that they could quickly be replaced in the right row of the breadboard if they accidentally came out...

Secret knock box gubbins: components labelled up to facilitate explaining what they were for, free ends of wires labelled up so that they could quickly be replaced in the right row of the breadboard if they accidentally came out...

Since it was only a ten minute activity, I decided to leave the components on the breadboard, rather than permanently soldering them up. It was also for this reason that I was reluctant to drill holes in the box I had acquisitioned to use as the casing. The downside of this being that there wasn’t really much in the way of a feedback mechanism, because the LEDs were not visible. As a compromise, I fitted a buzzer in the place of the door-knob opening motor so that the box would buzz when the correct knock was given. I also implied a lock through the way that I introduced the box and handled it in front of the children.

Here it is in action:

box with a secret knock in it. from nikkipugh on Vimeo.

When it was time for the kids to go into action, I reverted to the now familiar Agent N role and gave them an introduction that indicated that they were a specially selected team of code-breakers and we’d been given a mission to investigate this box.

I had some vague knowledge about such things, but I certainly didn’t hold any answers. After telling them they needed to find the secret knock, I handed them two folders containing stuff that might be clues and asked to “please tell me what you think”… I encouraged the children to help eachother out, and also to offer lots of different ideas and hypotheses.

A selection of clues from which the children successfully built up and interpreted a diagram of the secret knocks rythmn.

A selection of clues from which the children successfully built up and interpreted a diagram of the secret knock's rythmn.

From there I nudged and guided, seeking to let the pupils make the connections between the different clues wherever possible. We just managed to open the box in time!

The session was a bit slower and lower energy than I had imagined it would be. On reflection I think this was as much to do with nerves and shyness on the part of the pupils (I was the first artist they were interviewing) as much as anything in my control. Certainly the three children who had previously accompanied me on a tour of the school seemed more relaxed and outgoing than the others who had only just met me. The nice moment was when the Deputy Head came back to the room and asked what they had done. The description they gave, with no input from me, was spot-on and showed a sophisticated understanding of the principles involved.

Given the opportunity, I would love to expand this into a much longer activity in which we could solve the initial code, investigate how the box works and then – because obviously the code was too easy – reprogramme it with another knock and get the children to invent ways of codifying that information in an even more fiendishly difficult manner…