//https://github.com/SpenceKonde/ATTinyCore
//https://www.hackster.io/porrey/easy-serial-on-the-attiny-2676e6

#include <SoftwareSerial.h>

int sense_pin = A7; //ATtiny44 PA7
int charge_pin = 9; //ATtiny44 PB1
//note: rx and tx are reversed. (point of view of the board: transmitting (tx) to the computer's rx
int rx_pin = 11; //any pin not used //ATtiny44 PB3
int tx_pin = 4; 
int value2;
int value1;
int value;
int IN2 = 2;  //PA2
int IN1 = 3;  //PA3

SoftwareSerial Serial (rx_pin, tx_pin);

void setup() {
  Serial.begin(9600);
  pinMode (sense_pin, INPUT);
  pinMode (charge_pin, OUTPUT);
  pinMode (rx_pin, OUTPUT);
  pinMode (output_pin, OUTPUT);

  pinMode(IN2, OUTPUT);
  pinMode(IN1, OUTPUT);
  digitalWrite (IN1, LOW);
}

void loop() {

  digitalWrite(charge_pin, HIGH);
  delayMicroseconds(20); 
  value1 = analogRead(sense_pin);
  delayMicroseconds(200);
  
  digitalWrite(charge_pin, LOW);
  delayMicroseconds(20);
  value2 = 1023 - analogRead(sense_pin);
  delayMicroseconds(200);

  value = (value1 + value2) / 2;
  Serial.println(value);

  if (value<500 and value>10) {
     digitalWrite (IN2, HIGH);
     delay(4000); //inflate for a while
     digitalWrite (IN2, LOW); //then deflate
     delay(4000); //delay to make sure all the air is out before the next inflation
  }

}