How many Buttons W/ LED and Adafruit 2.13" eInk / ePaper Display on an Arduino could I use?

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el_barto_1
 
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How many Buttons W/ LED and Adafruit 2.13" eInk / ePaper Display on an Arduino could I use?

Post by el_barto_1 »

Hi,

I'm trying to build a device with an eInk display and some buttons with leds. I'm thinking to use an Arduino micro controller for it's simplicity and low cost but I'm not entirely sure how many I/O pins I would need/have left for LEDs and buttons after connecting the eInk Display.

The display I would be using is the Adafruit 2.13" 250x122 Tri-Color eInk / ePaper Display with SRAM - SSD1680 Driver
Product ID: 4947
I haven't purchased it yet so if there are better alternatives I would like to know!

As for the buttons and LED. I need to be able to control all the LEDs and detect all the buttons individually. And they need to come in pair (1 button for each LED, or a button with built in LED).

So,
Question 1: With 1 display and an Arduino UNO how many Button/LED pair could I get?

Question 2: What larger Arduino (or Arduino compatible) device could offer more Button/LED pairs and how many?

Question 3: Assuming I'll be able to use more that 1 LED/Button pair on a standard Arduino UNO, if I were to build a second device with the exact same functionality (Basically the same code) but with only 1 Button and LED, what would be the smallest Arduino compatible micro controller?

Thanks!

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adafruit_support_bill
 
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Re: How many Buttons W/ LED and Adafruit 2.13" eInk / ePaper Display on an Arduino could I use?

Post by adafruit_support_bill »

That display requires between 8 and 10 pins - depending on whether you need to use the (optional) Enable or Busy pins: https://learn.adafruit.com/adafruit-2-1 ... ns-3085373

A classic Arduino UNO has a total of 21 GPIO pins - 2 of which are required for uploading programs. That leaves you with between 9 and 11 pins for direct connection of buttons and LEDs.

That said, there are multiple options for interfacing larger numbers of buttons and LEDs:

The 'brute force' approach is to use something like the Grand Central with lots of GPIO: https://www.adafruit.com/product/4084

There are i2c GPIO expansion and LED driver boards requiring only 2 pins:
https://www.adafruit.com/product/4886

And then there is the Trellis which integrates multiple buttons & LEDs with an i2c interface that also only requires 2 pins: https://www.adafruit.com/product/1616

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