Microvision

In 1979, the Milton Bradley Company released a hand-held game console called the Microvision. Designed by Jay Smith, who later went on to design the Vectrex gaming console, the Microvision successfully combined a cartridge-based system with portability, grossing $8 million in the first year of the system's release. Unfortunately, the small (16x16 pixel) monochrome screen, lack of support from established home video game companies and subsequent lack of games led to the handheld console's demise in 1981.

Processors

The first Microvision cartridges were made with both Texas Instruments TMS1100 and Intel 8021 processors, but due to purchasing issues, Milton Bradley soon switched to using Texas Instruments processors exclusively. Although the TMS1100 was a more primitive device, it offered lower power consumption and more memory than the 8021.

Batteries

Due to the Intel 8021's greater power consumption, first-revision Microvisions needed two batteries to run the console. Later units designed for the TMS1100 only required one battery; however, due to the high cost of changing production moulds, the second battery compartment was not removed. Instead the terminals were removed and the slot was renamed as a spare battery holder.

Problems Developed by the Microvision

The Microvision units and cartridges were susceptible to three main problems: ESD (electrostatic discharge) damage, screen rot and keypad destruction.

ESD damage

One of the Microvision's major design flaws was that the microprocessor located at the top of each cartridge lacked electrostatic discharge protection and was connected directly to the copper pins that connect the cartridge to the Microvision unit. When opening up the protective sliding door that covered the pins, any electric charge the user had built up could be discharged around the door's edge or pass through the door itself, destroying the low-voltage integrated circuit inside the cartridge.

Screen Rot

Impurities and poor sealing introduced during the manufacturing process caused the Microvision to develop a condition known as screen rot, in which the liquid crystal spontaneously leaked and permanently darkened. Although the unit still worked, the game was unable to draw the screen properly. Unfortunately, there was nothing that could be done to prevent screen rot in most Microvisions.

Keypad Destruction

The Microvision unit had a twelve-button keypad, with the switches buried under a thick layer of flexible plastic. Each cartridge fitted over the console, with cutouts that aligned with the particular buttons required for that game. Each of these cutouts were covered with a thin printed piece of plastic, identifying the buttons' functions. However, when pressing these buttons during the game, the thin printed plastic often stretched and even tore.