As promised, this is going to be THE RADDEST module of them all, so here's a double whammy! Two logs in one day!

As I was scouring the Internet for some good Geiger Counter sounds, I stumbled upon this wonderful piece of code by [Samuelvdv] who uses a proprietary indoor positioning Arduino shield to make the  "Geiger counter" go off when approaching specific locations. If I could use (part of) this code to perhaps track a BLE beacon, that would allow me to create "radioactive" props for use with the Pip Boy.
In his article, he also links to an older project by [Jeff Haas] that uses a 1 Ohm speaker. Luck has it, I ordered a couple of those for another project of mine!
I managed to test out the sounds the "Geiger counter" makes. The speakers are super tiny, and only uses up one GPIO-pin and connects to GND.
The sound resonates pretty well in the Rad Module, so I think we can also consider the sound part of it all a big success! Now to cobble and code everything together!

I'm posting the code here with attribution just so I don't lose it myself ;).

// Geiger Counter - simulated sound effect by Jeff Haas
// Source: https://www.instructables.com/id/How-To-Make-A-Fake-Geiger-Counter/
// Connections:
// Arduino Pin 10 is toggled to create audio sound effect and goes to LM386 amp
// Arduino Pin 9 is the activate button, which must have a pull-up resistor on it
// An LED (which is optional) can connect to Pin 8 (and needs a current-limiting resistor and connection to ground)

// FINAL port on 5/25/2012


#include <inttypes.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/sleep.h>
#include <stdlib.h>
// #include "iocompat2.h"     Not needed in Arduino environment
// #include "pin_macros.h"    Not needed in Arduino environment

#define INIT_TIMER_COMP 0xffff  

#define LOWBYTE(val)  ((uint8_t)((val) & 0xff)) 
#define HIGHBYTE(val) ((uint8_t)(((val) & 0xff00) >> 8)) 

#define B_DATA_PORT_MASK (_BV(DDB0)) 

int foo(void) {        
    return 2;
}

void toggle_b2(void)  
{

    PORTB ^= _BV(PORTB2);
}

void led_out (uint8_t val) 
{
    unsigned char tval;   

    tval = PORTB & _BV(PORTB2);
    tval |= ~val & B_DATA_PORT_MASK;
    PORTB = tval;
}
void stop_timer1 (void) 
{
    TCCR1B = TCCR1B & ~(_BV(CS10) | _BV(CS11) | _BV(CS12));
}
void start_timer1 (void)
{

    TCCR1B |= _BV(WGM12); 
    
    TCCR1B |= _BV(CS12); /* clock prescale divide by 8 */  // Original non-Arduino value was CS11, in Arduino environment, set to (CS12), which is 256.

}

ISR (TIMER1_OVF_vect)    
{
    led_out(0x1);
}
void set_compare_timer1 (uint16_t val)
{
    OCR1AH = HIGHBYTE(val);
    OCR1AL = LOWBYTE(val);
}
typedef enum {
    UP,
    DOWN,
} SVAL;                    

#define INITSHIFT 0        


int sit = (5<<INITSHIFT);  
int shift = INITSHIFT;     

ISR (TIMER1_COMPA_vect)   
{
    static unsigned int delay = 0;
    static SVAL state = DOWN;
    int in = PINB;
    cli();                
    stop_timer1();
    toggle_b2();
    
    if (in & 0x2) {      
        state = DOWN;
        led_out(0);      
    } else {
        state = UP;
        led_out(1);      
    }

    delay = (rand() & 0xDEA8);  // Maximum length of the delay between clicks, a random number. Original value was 0xffff (65536).
    if (delay < 0x40) {          
    delay = 0x40;            
    }


    if (sit-- <= 0) {            
        switch (shift) {    

        case 0:
            if (state == UP) {
                shift = 2;
                sit = (5);
            } else {            
                shift = 0;
                sit = 1;
            }

            break;
        case 1:
        case 2:
            if (state == UP) {
                shift = 3;
                sit = 1;
            } else {            
                sit = 1;
        shift = 0;
            }

            break;
        case 3:
        case 4:
            if (state == UP) {
                sit = 1;
                shift = 3;
            } else {            
                sit = (10);
                shift = 1;
            }
            break;
        }
    }

    if (shift == 0) {
        set_compare_timer1(delay<<2);  
    } else {                               
        set_compare_timer1(delay>>shift);
    }
    start_timer1();

    led_out(shift);

    sei();            
}

void
ioinit (void)
{

    DDRB = B_DATA_PORT_MASK | _BV(DDB2); 

    PORTB = 0;

    TCCR1A = 0;
    TCCR1B = 0;

    set_compare_timer1(0x4000);  

    TCCR1A = 0;

    TCCR1B |=    _BV(WGM12); 

    TCCR1B |= _BV(CS11); 

}
#define JVAL 100000;
int
main (void)
{

    ioinit ();

    srandom(0x12345678);
    set_sleep_mode(SLEEP_MODE_IDLE);

    TIMSK1 = _BV (OCIE1A);
    cli();

    sei ();

    sleep_enable();
    sei();
    
    for (;;) {
    
    sleep_cpu();
    }
    return (0);
}