I picked up some colour LED modules for daylight readable displays.

From Aliexpress Store Shenzhen LCCL Opto-Electronic Science & Technology Co., Ltd.

Shown below driven by a LPC1768. (The normal commercial application uses FPGA to handle an array of these display to build a large screen)

The displays use a serial -> parallel led drive, data in is 6 bits wide (2 rows clocked in at once, RGB), and uses two 74HC138s to select 2/32 rows. This appears to be a fairly typical arrangement for this type of display. (the smaller displays only clock in a single row, but the principle is the same)

The display shown is a P4 (4mm pitch between pixels), P3 is also readily available.

I intend to enclose this in an IP rated box with a few basic IO and RS485 and CAN ports.

There will be a single screen and a 3 screen version (That would be a LPC1768 for each display) giving a 96 pixel x 64 pixel display.

Please contact me if you would like any further information.