[Kyle] has been an avid reader of HaD for a long time. In fact, he was inspired by a Halloween knock box from 4 years ago! He saved the link and finally this year, he went ahead and made his own.
So what is it anyway? Well, as the name implies, when you knock on it, it knocks back. And if you knock on it a special number of times, it’ll play a secret tune… It is a great little item to have at any Halloween event — and kids love it!
Design and function of the box is basically the same as the original, with a few modifications — most notably, swapping out the original PICAXE for an ATtiny85 microcontroller. [Kyle] even managed to find the lego skeleton and chains available on eBay. He’s put together a very thorough blog post on it and shared all the code and schematics — so if you’re looking for a last minute Halloween project, this might be it!
Stick around after the break to see the knocking in action!
Halloween is getting close! Don’t forget to send in your Halloween hacks to the tip-line!
Cool stuff! :)
Nice, just one suggestion, when he knocks “Shave and a hair cut” it should knock “2 bits”.
Yeah, that was my original intention; to have it knock the “2 bits” but the family was getting to anxious to play with it so I left it off. This may be an improvement I will add after Halloween.
The cheap/hackish way to do that would be just to do it for 5 knocks rather than looking for the pattern. Though I suppose after 5 knocks you could also just check that the delay after 2nd and 3rd knocks are “short” compared to delay after 1st and 4th knock. That’d be close enough to get the effect I bet without have to do a “closeness match” to the real pattern.
Nice! I like the LEGO skeleton too. :)
LEGO must never dye.
He used an Attiny45, but mentioned a 25 would be enough too.