[Ken Shirriff]’s analysis of a fascinating high-tech paperweight created by GE at the height of the space race is as informative as it is fun to look at. This device was created to show off GE’s thin-film electronics technology, and while it’s attractive enough on its own, there’s an added feature: as soon as the paperweight is picked up, it begins emitting a satellite-like rhythmic beep. It is very well-made, and was doubtlessly an impressive novelty for its time. As usual, [Ken] dives into what exactly makes it tick, and shares important history along the way.

Thin-film electronics reduced the need for individual components by depositing material onto a substrate to form things like resistors and capacitors. The resulting weight and space savings could be considerable, and close-ups of the thin film module sure look like a precursor to integrated circuits. The inside of the left compartment contains a tilt switch, a battery, a vintage earphone acting as a small speaker, and a small block of components connected to the thin-film module. This block contains two oscillators made with unijunction transistors (UJTs); one to create the beep, and one to control each beep’s duration. The construction and overall design of the device is easily recognizable, although some of the parts are now obsolete.
If you’d like a bit more detail on exactly how this device worked, including circuit diagrams and historical context, be sure to click that first link, and pay attention to the notes and references at the end. One other thing that’s clear is that functional electronics embedded in clear plastic shapes simply never go out of style.






What sets this apart from other jet models is the working reverse thrust system. [Harcoreta] painstakingly modeled the cascade reverse thrust setup on the 787/GEnx-1B combo. He then engineered a way to make it actually work using radio controlled plane components. Two servos drive threaded rods. The rods move the rear engine cowling, exposing the reverse thrust ducts. The servos also drive a complex series of linkages. These linkages actuate cascade vanes which close off the fan exhaust. The air driven by the fan has nowhere to go but out the reverse thrust ducts. [Harcoreta’s] videos do a much better job of explaining how all the parts work together.
