Digispark ATtiny85 keyboard

Question

I have a small project that I have in mind and I'm pretty new with Arduino.

I want to make a small device that if a key was pressed it would do something.

Now I know I could use a button with the device but I want to specifically use a Cherry MX Blue Switch.

So I wanted to know if the test code I wrote up would get me in the right stating place and I want to know where I would wire the key switch onto the board.

From how I have the code written I'm guessing I connect the positive pin from the switch to P0 on the board and the other pin to ground on the board, is this correct?

#include "DigiKeyboard.h"

void setup() {
    pinMode(0, INPUT);
}

void loop() {
    // put your main code here, to run repeatedly:
    if(digitalRead(0)==HIGH){
        DigiKeyboard.sendKeyStroke(MOD_GUI_LEFT,KEY_R);
        DigiKeyboard.print("test");
    }
}

Answer 1

I would suggest to connect one pin of the with to 5v and the other to ground. The Arduino will be able to detect 5v as logic HIGH.

The code looks correct except for better programming technique I would suggest to indent you code, this make debugging easier for longer programs:

#include "DigiKeyboard.h"

void setup() {

   pinMode(0, INPUT);

}

void loop() {
  // put your main code here, to run repeatedly:

  if(digitalRead(0)==HIGH){

    DigiKeyboard.sendKeyStroke(MOD_GUI_LEFT,KEY_R);
    DigiKeyboard.print("test");

  }
}

Answer 2

Do you want the absolute lowest power consumption? If yes then instead of using a microcontroller, use a dual D type latch. The circuit below will take the first break of the optical beam, turn on the output for that latch, and will block the other latch from turning on.

When the clock input goes high (beam broken) the high on the D input is transferred to Q and -Q will go low. That low will force the output of the other latch to stay low.

To reset the light the push button switch is used to clear the Q output. It is then ready again.

I didn't show the power supply (bypass cap). The chip is a CD74HC74. 14 pins containing two latches.The only current drawn is the LED current and the current of the opto-transistors.