The Secret Knock in the Box talks back

Remember the Secret Knock in A Box? Over the last couple of months I’ve had the support of Aston University’s School of Engineering & Applied Science to make a prototype PCB so that I can develop a kit for making it.

Here’s the first one we’ve made:

First PCB design (with additional hot melt glue strands, for effect)

The basic circuit works and I’m also trying out a piezo element as the knock detector. It’s very sensitive!

As well as adjusting the sensitivity, I want to explore how the box responds when you give it the correct secret knock: should it unlock itself? should it disarm an alarm? should it … ?

Here’s a little experiment towards making it knock back. Thanks to GB and his help, last night at fizzPOP we managed to get the box to buzz back the correct knock once it had been entered.

Responding Secret Knock in the Box from nikkipugh on Vimeo.

Next step is probably to get to grip with transistors so I can then include a solenoid to knock instead of buzz.