Hacking Childhood Memories: A tale of reverse engineering, audio encodings, and never growing up

Jeremy Trimble

The original "Speak & Spell" toy was released in 1978 and featured some fairly cutting-edge technology in order to generate a synthetic human voice at a fairly low price point. Classic Speak & Spells have been widely hacked, reverse-engineered, and "circuit-bent."

In 2019, a re-release of the Speak & Spell came out with a classic vintage exterior but drastically simplified and cost-reduced electronics inside. This version seems to have been largely ignored by the hacking/reversing community (until now). When my daughters asked me to repair their 2019 S&S, what I found inside totally nerd-sniped me, kicking off a journey down the reverse-engineering rabbit hole.

Typical static reverse engineering tools like strings/binwalk/libmagic weren't any help, so I got back to basics, relying on my logic analyzer, oscilloscope, and em100 SPI flash emulator to observe behaviors at run-time and write my own tools along the way.

In this talk we'll see live demos of the experiments I used to reverse engineer the 2019 S&S flash data format and its audio codec, and release code to let you compile a custom "voice pack" for your own 2019 Speak&Spell. A certain iconic celebrity voice may even make an appearance...

Speaker Bio:

Jeremy Trimble is a dad, engineer, and hacker/maker who loves figuring out how things work and bending technology to his will. Jeremy is currently Chief Scientist at TwoSix Technologies Electronic Systems where he builds and hacks somewhat more complicated toys.