Eggcrate Displays

An eggcrate display is a matrix of incandescent lamps that is designed to show patterns of bitmapped data. Typically, for numeric data, these come in a five column by seven row configuration with some empty cells, use 28 volt lamps, and have diode steering logic map out the pixels to each number.

Eggcrate displays were commonly used on the set of television game shows from 1971 to 2017 to display numeric information such as score, monetary amounts, and time remaining. The Price is Right is the only show to still use eggcrate displays in a select few props to this day, with the oldest surviving example being the Race Game from 1974.

You can find eggcrate displays in studio surplus shops where old props have gone away after being retired.

No, like with numitron displays, these are incandescent and do not multiplex well.

Reference the common pin of the Molex connector at the back of the display (pin 11) to the positive of a high-power 28 volt supply. From here, there are two options you have...

Option 1: The TTL Drive Method

Use a 74LS42 with a 2N3906 and TIP122 transistor pair on each output to drive each digit. Use 0 to 5 volt signals to control what number lights in the display.

Note: The TIP122 transistors should be left open collector.

Option 2: The CMOS Drive Method

Use a CD4028 with an IRFZ44 MOSFET on each output to drive each digit. The inputs get signals going from V_SS for the low state to V_DD for the high state.

Use caution when working with CMOS components or MOSFETs. Any amount of static discharge can permanently damage such components.