Replicating the Classic "Mystifier" Toy

When the practical applications of electricity first started appearing in the 19th century, most of the population found it to be mysterious and almost magical. Spectators would gather to see demonstrations of electricity that would seem mundane today. Even simple incandescent light bulbs were an attraction. This happened again when digital electronics came along. People wanted to see them in action, but in the '60s computers were very expensive and few had to access to them. To meet demand, manufacturers designed toys that seemed to possess the new technology. One of those toys was the Eicocraft EC-700 Electronic Mystifier and Brent Hauser replicated that toy using modern components.

Eicocraft released the EC-700 Electronic Mystifier as a hobbyist kit in the 1960s. Once assembled, the device would blink six neon lights at random. At the time, the randomly-blinking lights were pretty impressive. In reality, the lights weren't blinking at random. RC relaxation oscillators, typically used for turn signals and other low-frequency signals, controlled each light. But those were interconnected and had different timings, which made the lights appear as if they were blinking at random. The Mystifier had no practical purpose, but it was mesmerizing to people at the time, like a lava lamp or plasma globe.

Hauser has been creating his own Mystifier devices for almost 20 years now. His original versions were attempts to recreate to Eicocraft-designed circuit. But his most recent version ditches the RC relaxation oscillators altogether in favor of a modern digital microcontroller. A Microchip PIC16F microcontroller has firmware written to utilize a pseudo-random number generator (PRNG) based on a 16-bit LFSR (Linear-Feedback Shift Register). It uses those random numbers to control the timing of the lights. Those lights are small neon lamps similar to the type used in the real EC-700 Electronic Mystifier. They require 100V, which comes from a boost converter driven by the PIC16F.

Because this circuit is digital, the blink rate is easy to adjust. Hauser's firmware lets users select anything from one to seven blinks per second. He also designed a custom PCB for the project and made it available through OSHPark. If you want to build your own Mystifier, you can order that PCB and the other components — just make sure that you have a way to program the PIC16F with the provided firmware. This device may not be as mystical as it was in the '60s, but it still makes for a cool desk toy.