Automated Medication Dispenser

#include <Arduino.h>
#include <ESP32Servo.h>
#include <HX711.h>
// BENCH PROTOTYPE ONLY. No schedule or automatic retries. Power loss loses state.
const int servoPins[]={13,14,16,17}, tubePins[]={34,35,36,39}, ledPins[]={18,19,21,22};
const int counterPin=32, alarmLed=23, buzzerPin=26;
// Verify each module's polarity with STATUS before using test pieces.
const int PRESENT=LOW;
const int CLOSED=0, OPEN=60;
Servo gates[4]; HX711 scale;
enum State {IDLE, OPENING, SETTLING, READY, FAULT};
State state=IDLE;
bool calibrated=false,tared=false; float factor=0,weight=0,baseline=0,expected=0,tolerance=0;
long raw=0; unsigned long sampleAt=0,stageAt=0,stableAt=0,edgeAt=0;
int tube=0,count=0; bool lastBeam=false,beam=false; unsigned long beamAt=0;
String line;
void closeAll(){for(auto &s:gates)s.write(CLOSED);}
void fail(const char*why){closeAll();state=FAULT;Serial.print("FAULT: ");Serial.println(why);}
void setup(){
 Serial.begin(115200); line.reserve(100);
 for(int i=0;i<4;i++){pinMode(tubePins[i],INPUT);pinMode(ledPins[i],OUTPUT);gates[i].setPeriodHertz(50);gates[i].attach(servoPins[i],500,2400);gates[i].write(CLOSED);}
 pinMode(counterPin,INPUT);pinMode(alarmLed,OUTPUT);pinMode(buzzerPin,OUTPUT);scale.begin(33,25);
 Serial.println("BENCH ONLY. Commands: STATUS, TARE, CAL grams, DO tube grams tolerance, RESET. Use non-medical test pieces.");
}
void command(String s){
 s.trim();s.toUpperCase();
 if(s=="STATUS"){Serial.printf("state=%d raw=%ld weight=%.3fg count=%d calibrated=%d tared=%d beam=%d tubes:",state,raw,weight,count,calibrated,tared,digitalRead(counterPin));for(int p:tubePins)Serial.printf(" %d",digitalRead(p));Serial.println();return;}
 if(s=="RESET"){closeAll();state=IDLE;tared=false;Serial.println("Inspect and empty tray; TARE required. No automatic retry.");return;}
 if(state!=IDLE){Serial.println("Busy/fault. Inspect first, then RESET.");return;}
 if(millis()-sampleAt>500){Serial.println("Scale unavailable");return;}
 if(s=="TARE"){scale.set_offset(raw);weight=0;tared=true;Serial.println("Empty tray zero recorded; keep tray installed.");return;}
 float grams=0,tol=0;int t=0;
 if(sscanf(s.c_str(),"CAL %f",&grams)==1 && grams>0 && tared){factor=float(raw-scale.get_offset())/grams;if(fabsf(factor)<1){Serial.println("Calibration rejected");return;}scale.set_scale(factor);calibrated=true;Serial.println("Calibration stored in RAM only. Remove reference mass; TARE empty tray.");tared=false;return;}
 if(sscanf(s.c_str(),"DO %d %f %f",&t,&grams,&tol)==3){
 if(!calibrated||!tared||t<1||t>4||grams<=0||tol<=0||tol>=grams/2){Serial.println("Need calibration, tare, tube 1..4, expected grams, tolerance < half mass.");return;}
 if(fabsf(weight)>tol||digitalRead(counterPin)==PRESENT||digitalRead(tubePins[t-1])!=PRESENT){Serial.println("Tray not empty, counter blocked, or tube low.");return;}
 tube=t-1;expected=grams;tolerance=tol;baseline=weight;count=0;lastBeam=false;beam=false;beamAt=millis();stageAt=millis();state=OPENING;gates[tube].write(OPEN);return;
 }
 Serial.println("Unknown command");
}
void loop(){
 unsigned long now=millis();
 if(scale.is_ready()){raw=scale.read();sampleAt=now;weight=calibrated?float(raw-scale.get_offset())/factor:0;}
 for(int i=0;i<4;i++)digitalWrite(ledPins[i],digitalRead(tubePins[i])!=PRESENT);
 bool observed=digitalRead(counterPin)==PRESENT;
 if(observed!=beam){beam=observed;beamAt=now;}
 if(now-beamAt>=5 && beam!=lastBeam){lastBeam=beam;if(beam&&(state==OPENING||state==SETTLING||state==READY)){count++;edgeAt=now;if(count>1)fail("More than one counter event");}}
 if(state==OPENING||state==SETTLING||state==READY){
 if(now-sampleAt>700)fail("Scale stopped responding");
 else if(beam&&now-beamAt>1200)fail("Counter blocked");
 }
 if(state==OPENING && (count>=1 || now-stageAt>=350)){gates[tube].write(CLOSED);state=SETTLING;stageAt=now;stableAt=now;}
 if(state==SETTLING){
 float delta=weight-baseline;
 if(fabsf(delta-expected)>tolerance)stableAt=now;
 if(now-stageAt>1000 && count==1 && now-stableAt>=1000 && !beam){state=READY;stageAt=now;stableAt=now;Serial.printf("READY: count=1 mass=%.3fg. Collect test piece; leave tray fitted.\n",delta);}
 else if(now-stageAt>6000)fail("Count or settled weight mismatch; inspect manually");
 }
 if(state==READY){
 if(fabsf(weight-baseline)>tolerance)stableAt=now;
 if(now-stableAt>=1500){state=IDLE;tared=false;Serial.println("Tray appears empty. Inspect, then TARE before next test.");}
 }
 bool alarm=(state==READY||state==FAULT)&&((now/300)%2==0);
 digitalWrite(alarmLed,alarm);if(alarm)tone(buzzerPin,4000);else noTone(buzzerPin);
 while(Serial.available()){char c=Serial.read();if(c=='\n'){command(line);line="";}else if(c!='\r'&&line.length()<99)line+=c;}
 delay(1);
}

// Wiring verified: tube inputs use input-only GPIOs; servo outputs pass through AHCT buffer.