Hi guys,
I'm looking for some help/advice. I'm currently starting working on replicating a cockpit of a fighter-jet at home and I will have to drive 30 7segment displays that are 2.5-2.7V input range. Everything I found online talks about 3.3V and 5V. I plan to use Arduino mega 2560, as it has lots of pins and this panel requires it, since it will have a few pushbuttons and switches.
This voltage is the LED's forward voltage, your power supply must deliver at least this voltage for the LED to turn on
You can drive all these displays with a few MAX7219 chips, I suggest using 5 chips, each driving 6 displays, for consistent brightness (set the "scan limit" parameter accordingly)
Edit: I forgot to say, you need common cathode displays if you want to drive them easily with MAX7219 and the existing arduino libraries, the ones in your link are common anode
It's a very interesting project.
I think this video helps you.
In specification, your chosen LED will draw 10mA at 2.5V.
So you can guess that the resistance of that LED is 250 ohm.
If you are using 5V, connect a 250 ohm resistor in series with each LED.
This is a power operation and would require 30 shift registers. If you want to reduce the amount of wiring, consider using MAX7219 @guix suggested.
If you do not understand how to use them, you can ask questions as often as you like.
Why?
Why should anyone use a shift register for 7 segment displays when there are LED driver chips like MAX7219, HT16K33, TM1637, TM1638 ...
Each of these ICs made for the purpose to drive LED Displays.
Broad support with Arduino libraries.
No permament update of these IC necessary.
Several test boards available which enable users to start easy with working hardware.
But why would anyone suggest a shift register if there are better alternatives ?!?
@skyblockpro1 : if you need some suggestions let me know, but I guess you will find tons of examples with the above IC's including some premade displays to give you a quick start! If you are happy with one of the LED driver ICs it is still up to you to make your own custom PCB.
When you need it flickerfree (when moving the head or filming the display).
I would probably take a look at the HT16K33. It supports 16 7-segment displays and a 13x3 keyboard matrix. You can control 8 of these chips on one I2C bus (which only takes 2 pins on the Arduino).
