“There are few choices if you need a display that can be seen from across the room, a big display. You can make one like my ‘time squared’ or ‘leds on glass’ but this takes about 40 hours of tedious work. So here is an EASY to make large display. The build has 4 basic wires, 5 volts, ground, SDA, SCL. Each character display cost about two to three dollars. So a 8x2 display is about $30. Not counting RTC, Arduino, 3d prints, enclosure.
The sketch is basic and easy to understand. Easy to modify for any alphanumeric display. The letters are 1/2 size with 1/2 size numbers and a set of full size numbers.
The drawback is you can only make a display of 64 char. The TCA9548 runs out of addresses (8). The Hitachi lcd is very SLOW and any larger display and the write time takes about a full second to fill the entire display. So if you wanted a wall size display it will be slow. There are many ways to cheat and use more than 64 lcds but I will not cover that in this post as this is an EASY to make display.
YES the photos of a LCD……DO NOT come out well. These displays look GREAT in real life.
Supplies:
Any uno 328 … nano, pro-mini, uno…
popular RTC ZS-042 module (DS3231)
TCA9548 I2c mux splitter
Hitachi 1602 with backpack I2c as many as 64
3d print of pcb cover. I have 2 types to choose from
wooden enclosure like a picture frame made from 1.5 inch wood trim (stock at Lowes)
basic skills : solder, wire, hookup, adj, M2 nuts and bolts”