This is a great project that reuses an LED display found on buses in the 1990s. Translated from the original:
I recently recovered a display bus brand DATA Display (1992, at the sight of datecode components). The display consists of two parts:
- Part of a top, consisting of two green segments 12 of dies (7 × 5 each), or a large array of (2 * (12 * 5)) * 7 pixels.
- The bottom part, a bit the same, but with red pixels
The bottom part is interesting because it seems to contain a RAM, with external connection (and a NiMH battery to retain RAM) can be upload messages to display. By cons, manufacturers do not have the transmission protocol. It will be a bit boring to reverse-engeenirer.
The top part, it is almost identical. Except that it contains a ROM containing the characters ASCII (at least, their representation in matrix 5 × 7) to display the text. It also has a special connection (RS232, but not too much). It’s going to be boring to do. But I decided to disassemble the upper display and watch how it worked.