Reduce temperature limits for testing

barista/.gitignore

@@ -1 +1,3 @@
 build/
+test_ntc
+*.o

barista/Makefile

@@ -1,17 +1,35 @@
+# Copyright (c) 2025 Rodrigo Arias Mallo <rodarima@gmail.com>
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 PORT=/dev/ttyUSB0
 FQBN=arduino:avr:atmega328bb
-OPTS=--no-color --log-level=info -v
+OPTS=--no-color --log-level=info
+#OPTS+=-v
 PROJ=barista
 BUILD=build/$(subst :,.,$(FQBN))
 HEX=$(BUILD)/$(PROJ).ino.hex
 
+# For host test programs
+CPPFLAGS=-I.
+LIBS=-lm
+
 all: $(HEX)
 
-$(HEX): barista.ino
+$(HEX): barista.ino ntc.c ntc.h pinout.h
 	arduino-cli compile $(OPTS) -e --fqbn $(FQBN)
 
 upload: $(HEX)
 	avrdude -vv -p atmega328p -c arduino -P $(PORT) -b 9600 -D -U flash:w:$(HEX):i
 
 serial:
-	picocom -b 115200 --lower-rts --lower-dtr /dev/ttyUSB0 --imap lfcrlf
+	picocom -b 9600 --lower-rts --lower-dtr /dev/ttyUSB0 --imap lfcrlf
+
+test: test_ntc
+
+test_ntc: test/test_ntc.o ntc.o
+	gcc $^ -o $@ $(LIBS)
+
+clean:
+	rm -f test/test_ntc.o ntc.o
+
+.PHONY: test all clean

barista/barista.ino

@@ -1,64 +1,8 @@
 /* Copyright (c) 2025 Rodrigo Arias Mallo <rodarima@gmail.com>
  * SPDX-License-Identifier: GPL-3.0-or-later */
 
-/*
- *                             ATmega328p
- *                            +---------+
- *  (PCINT14/RESET)      PC6 -|1  \_/ 28|- PC5 (ADC5/SCL/PCINT13)
- *  (PCINT16/RXD)        PD0 -|2      27|- PC4 (ADC4/SDA/PCINT12)
- *  (PCINT17/TXD)        PD1 -|3      26|- PC3 (ADC3/PCINT11)
- *  (PCINT18/INT0)       PD2 -|4      25|- PC2 (ADC2/PCINT10)
- *  (PCINT19/OC2B/INT1)  PD3 -|5      24|- PC1 (ADC1/PCINT9)
- *  (PCINT20/XCK/T0)     PD4 -|6      23|- PC0 (ADC0/PCINT8)
- *  VCC                      -|7      22|-     GND
- *  GND                      -|8      21|-     AREF
- *  (PCINT6/XTAL1/TOSC1) PB6 -|9      20|-     AVCC
- *  (PCINT7/XTAL2/TOSC2) PB7 -|10     19|- PB5 (SCK/PCINT5)
- *  (PCINT21/OC0B/T1)    PD5 -|11     18|- PB4 (MISO/PCINT4)
- *  (PCINT22/OC0A/AIN0)  PD6 -|12     17|- PB3 (MOSI/OC2A/PCINT3)
- *  (PCINT23/AIN1)       PD7 -|13     16|- PB2 (SS/OC1B/PCINT2)
- *  (PCINT0/CLKO/ICP1)   PB0 -|14     15|- PB1 (OC1A/PCINT1)
- *                            +---------+
- *
- * 
- *         ATMEL ATMEGA8 & 168 / ARDUINO
- *
- *                          +-\/-+
- *                    PC6  1|    |28  PC5 (AI 5)
- *              (D 0) PD0  2|    |27  PC4 (AI 4)
- *              (D 1) PD1  3|    |26  PC3 (AI 3)
- *              (D 2) PD2  4|    |25  PC2 (AI 2)
- *         PWM+ (D 3) PD3  5|    |24  PC1 (AI 1)
- *              (D 4) PD4  6|    |23  PC0 (AI 0)
- *                    VCC  7|    |22  GND
- *                    GND  8|    |21  AREF
- *                    PB6  9|    |20  AVCC
- *                    PB7 10|    |19  PB5 (D 13)
- *         PWM+ (D 5) PD5 11|    |18  PB4 (D 12)
- *         PWM+ (D 6) PD6 12|    |17  PB3 (D 11) PWM
- *              (D 7) PD7 13|    |16  PB2 (D 10) PWM
- *              (D 8) PB0 14|    |15  PB1 (D 9) PWM
- *                          +----+
- *
- *
- */
-
-enum pinout {
-	/* Inputs */
-	PIN_POWER_ON  = 8,
-	PIN_HOT       = 9,
-	//PIN_FLOW      = PIN_D5,
-
-	/* Outputs */
-	PIN_LED_GREEN = 5,
-	PIN_LED_RED   = 6,
-	PIN_HEAT      = 7,
-	PIN_PUMP      = 12,
-	PIN_BUZZ      = 10,
-
-	/* Analog */
-	PIN_NTC       = PIN_A0,
-};
+#include "ntc.h"
+#include "pinout.h"
 
 enum logic {
 	ON = 1,
@@ -66,13 +10,13 @@ enum logic {
 };
 
 #define DEBOUNCE_TIME 20L /* ms */
-#define TEMP_MIN 600
-#define TEMP_MAX 700
+#define TEMP_MIN 40.0f /* C */
+#define TEMP_MAX 50.0f /* C */
 
 #define LED_MIN_VALUE 0
 
-enum state {
-	SLEEPING,
+enum machine_state {
+	SLEEPING = 0,
 	DEBOUNCE,
 	HEATING,
 	HOT,
@@ -80,16 +24,15 @@ enum state {
 	COOLING,
 };
 
-long debounce_t0 = 0;
-int state = SLEEPING;
+//int state = SLEEPING;
 
-enum button {
-	BUTTON_ON = 0,
-	BUTTON_HOT,
-	MAX_BUTTON,
+enum btn_index {
+	BTN_ON = 0,
+	BTN_HOT,
+	MAX_BTN,
 };
 
-enum button_state {
+enum btn_state {
 	RESTING = 0,
 	PRESSING,
 	PRESSED,
@@ -98,21 +41,48 @@ enum button_state {
 };
 
 enum buzz_state {
-  BUZZ_OFF = 0,
-  BUZZ_HEY,
-  BUZZ_STOP,
+	BUZZ_OFF = 0,
+	BUZZ_HEY,
+	BUZZ_ACTIVE,
 };
 
-int buzz_state;
 
-int button_pin[MAX_BUTTON] = {
-	[BUTTON_ON] = PIN_POWER_ON,
-	[BUTTON_HOT] = PIN_HOT,
+int button_pin[MAX_BTN] = {
+	[BTN_ON] = PIN_POWER_ON,
+	[BTN_HOT] = PIN_HOT,
 };
 
-int button_state[MAX_BUTTON];
-unsigned long button_press_t0[MAX_BUTTON];
-unsigned long button_release_t0[MAX_BUTTON];
+struct btn {
+	enum btn_state state;
+	unsigned long press_t0;
+	unsigned long release_t0;
+};
+
+struct input {
+	unsigned long t_ms;
+	int ntc_V;
+	enum logic btn[MAX_BTN];
+} g_in;
+
+#define MAX_SAMPLES 16
+
+struct state {
+	enum machine_state mstate;
+	unsigned long brewing_t0;
+	unsigned long cooling_t0;
+	unsigned long heating_t0;
+	unsigned long hot_t0;
+
+	int ntc_i; /* Next available place */
+	float ntc_R;
+	float ntc_last_T;
+	float ntc_array_T[MAX_SAMPLES];
+	float ntc_T; /* average */
+
+	struct btn btn[MAX_BTN];
+	enum buzz_state buzz_state;
+	unsigned long buzz_t0;
+} g_st;
 
 int read_input(int pin)
 {
@@ -121,51 +91,79 @@ int read_input(int pin)
 
 void relay(int pin, enum logic st)
 {
-  /* Relays are active low */
-  if (st == ON)
-    digitalWrite(pin, 0);
-  else
-    digitalWrite(pin, 1);
+	/* Relays are active low */
+	if (st == ON)
+		digitalWrite(pin, 0);
+	else
+		digitalWrite(pin, 1);
 }
 
 void setled(int pin, enum logic st)
 {
-  /* LEDs are active high */
-  if (st == ON)
-    digitalWrite(pin, 1);
-  else
-    digitalWrite(pin, 0);
+	/* LEDs are active high */
+	if (st == ON)
+		digitalWrite(pin, 1);
+	else
+		digitalWrite(pin, 0);
 }
 
-void update_buttons()
+void do_input(struct input *input)
 {
-	for (int i = 0; i < MAX_BUTTON; i++) {
-		int st = button_state[i];
-		int pin = button_pin[i];
-		if (st == RESTING) {
-			if (read_input(pin) == ON) {
-				button_state[i] = PRESSING;
-				button_press_t0[i] = millis();
+	input->t_ms = millis();
+
+	/* Read buttons */
+	for (int i = 0; i < MAX_BTN; i++)
+		input->btn[i] = read_input(button_pin[i]);
+
+	/* Read temperature sensor */
+	input->ntc_V = analogRead(PIN_NTC);
+}
+
+void proc_ntc(struct state *state, const struct input *input)
+{
+	state->ntc_R = ntc_resistance(input->ntc_V);
+	state->ntc_last_T = ntc_temp(state->ntc_R);
+	state->ntc_array_T[state->ntc_i++] = state->ntc_last_T;
+	if (state->ntc_i >= MAX_SAMPLES)
+		state->ntc_i = 0;
+
+	float avg = 0;
+	for (int i = 0; i < MAX_SAMPLES; i++)
+		avg += state->ntc_array_T[i];
+
+	state->ntc_T = avg / MAX_SAMPLES;
+}
+
+void proc_buttons(struct state *state, const struct input *input)
+{
+	for (int i = 0; i < MAX_BTN; i++) {
+		struct btn *btn = &state->btn[i];
+		int v = input->btn[i];
+
+		if (btn->state == RESTING) {
+			if (v == ON) {
+				btn->state = PRESSING;
+				btn->press_t0 = millis();
 			}
-		} else if (st == PRESSING) {
-			if (read_input(pin) != ON) {
-				button_state[i] = RESTING;
-			} else if (millis() - button_press_t0[i] > DEBOUNCE_TIME) {
-				button_state[i] = PRESSED;
+		} else if (btn->state == PRESSING) {
+			if (v != ON) {
+				btn->state = RESTING;
+			} else if (millis() - btn->press_t0 > DEBOUNCE_TIME) {
+				btn->state = PRESSED;
 			}
-		} else if (st == PRESSED) {
-			if (read_input(pin) != ON) {
-				button_state[i] = RELEASING;
-				button_release_t0[i] = millis();
+		} else if (btn->state == PRESSED) {
+			if (v != ON) {
+				btn->state = RELEASING;
+				btn->release_t0 = millis();
 			}
-		} else if (st == RELEASING) {
-			if (read_input(pin) == ON) {
-				button_state[i] = PRESSED;
-			} else if (millis() - button_release_t0[i] > DEBOUNCE_TIME) {
-				button_state[i] = RELEASED;
+		} else if (btn->state == RELEASING) {
+			if (v == ON) {
+				btn->state = PRESSED;
+			} else if (millis() - btn->release_t0 > DEBOUNCE_TIME) {
+				btn->state = RELEASED;
 			}
-		} else if (st == RELEASED) {
-			button_state[i] = RESTING;
+		} else if (btn->state == RELEASED) {
+			btn->state = RESTING;
 		}
 	}
 }
@@ -174,148 +172,156 @@ int red_min = 50;
 int red_state = red_min;
 unsigned long brewing_time     = 3000UL; /* 3 seconds */
 unsigned long cooling_time     = 3000UL; /* 3 seconds */
-unsigned long max_heating_time = 10000UL; /* 10 seconds */
+unsigned long max_heating_time = 60000UL; /* 60 seconds */
 unsigned long max_idle_time    = 10000UL; /* 10 seconds */
 
-void progress()
+void proc_machine(struct state *st)
 {
-	int temp = analogRead(PIN_NTC);
-	int on = (button_state[BUTTON_ON] == RELEASED);
-	int hot = (button_state[BUTTON_HOT] == PRESSED);
+	float temp = st->ntc_T;
+	int on = (st->btn[BTN_ON].state == RELEASED);
+	int hot = (st->btn[BTN_HOT].state == PRESSED);
 
-  static unsigned long brewing_t0 = 0;
-  static unsigned long cooling_t0 = 0;
-  static unsigned long heating_t0 = 0;
-  static unsigned long hot_t0 = 0;
-
-	Serial.print("state=");
-	Serial.print(state);
+	Serial.print("t=");
+	Serial.print(millis());
+	Serial.print(" state=");
+	Serial.print(st->mstate);
 	Serial.print(" on=");
 	Serial.print(on);
 	Serial.print(" temp=");
-	Serial.println(temp);
+	Serial.print(temp);
+	Serial.println(" C");
 
-  /* Pressing ON cancels any operation */
-	if (state != SLEEPING && on) {
-			state = SLEEPING;
-      return;
-  }
+	/* Pressing ON cancels any operation */
+	if (st->mstate != SLEEPING && on) {
+		st->mstate = SLEEPING;
+		st->buzz_state = BUZZ_OFF;
+		return;
+	}
 
-	if (state == SLEEPING) {
+	if (st->mstate == SLEEPING) {
 		if (on) {
-			state = HEATING;
-      heating_t0 = millis();
+			st->mstate = HEATING;
+			st->heating_t0 = millis();
 			Serial.println("heating");
 		}
-	} else if (state == HEATING) {
-    if (temp > TEMP_MAX) {
-      state = HOT;
-      hot_t0 = millis();
-      buzz_state = BUZZ_HEY;
-      Serial.println("hot");
-    } else if (millis() - heating_t0 > max_heating_time) {
-      /* TODO: Add alarm state */
-      state = SLEEPING;
-      Serial.println("cannot heat, going to sleep");
-    }
-	} else if (state == HOT) {
+	} else if (st->mstate == HEATING) {
+		if (temp > TEMP_MAX) {
+			st->mstate = HOT;
+			st->hot_t0 = millis();
+			st->buzz_state = BUZZ_HEY;
+			Serial.println("hot");
+		} else if (millis() - st->heating_t0 > max_heating_time) {
+			/* TODO: Add alarm state */
+			st->mstate = SLEEPING;
+			Serial.println("cannot heat, going to sleep");
+		}
+	} else if (st->mstate == HOT) {
 		if (hot) {
-			state = BREWING;
-      brewing_t0 = millis();
-      Serial.println("brewing");
-    } else if (millis() - hot_t0 > max_idle_time) {
-      state = SLEEPING;
-      Serial.println("idle timeout, going to sleep");
-    }
-	} else if (state == BREWING) {
-    if (millis() - brewing_t0 > brewing_time) {
-      state = COOLING;
-      cooling_t0 = millis();
-      Serial.println("cooling");
-    }
-  } else if (state == COOLING) {
-    /* TODO: Wait a bit and go back to heating */
-    if (millis() - cooling_t0 > cooling_time) {
-      state = HEATING;
-      heating_t0 = millis();
-      Serial.println("heating");
-    }
-  }
+			st->mstate = BREWING;
+			st->brewing_t0 = millis();
+			Serial.println("brewing");
+		} else if (millis() - st->hot_t0 > max_idle_time) {
+			st->mstate = SLEEPING;
+			Serial.println("idle timeout, going to sleep");
+		}
+	} else if (st->mstate == BREWING) {
+		if (millis() - st->brewing_t0 > brewing_time) {
+			st->mstate = COOLING;
+			st->cooling_t0 = millis();
+			Serial.println("cooling");
+		}
+	} else if (st->mstate == COOLING) {
+		/* TODO: Wait a bit and go back to heating */
+		if (millis() - st->cooling_t0 > cooling_time) {
+			st->mstate = HEATING;
+			st->heating_t0 = millis();
+			Serial.println("heating");
+		}
+	}
 }
 
 void
-update_leds()
+proc_buzz(struct state *st)
 {
-  static int r = 0;
-  static int g = 0;
+	if (st->buzz_state == BUZZ_HEY) {
+		tone(PIN_BUZZ, 1500);
+		st->buzz_state = BUZZ_ACTIVE;
+		st->buzz_t0 = millis();
+	} else if (st->buzz_state == BUZZ_ACTIVE) {
+		if (millis() - st->buzz_t0 > 20) {
+			st->buzz_state = BUZZ_OFF;
+			noTone(PIN_BUZZ);
+		}
+	} else {
+		noTone(PIN_BUZZ);
+	}
+}
 
-  if (state == HEATING || state == COOLING) {
-      analogWrite(PIN_LED_RED, r);
-      setled(PIN_LED_GREEN, 0);
-      if (r >= 255)
-        r = 0;
-      else
-        r += 3;
-  } else if (state == HOT) {
-      setled(PIN_LED_RED, 0);
-      setled(PIN_LED_GREEN, 1);
-      r = 0;
-  } else if (state == BREWING) {
-      setled(PIN_LED_RED, 0);
-      analogWrite(PIN_LED_GREEN, g);
-      if (g >= 255)
-        g = 0;
-      else
-        g += 3;
-  } else {
-      setled(PIN_LED_RED, 0);
-      setled(PIN_LED_GREEN, 0);
-      r = 0;
-  }
+void do_proc(struct state *st, const struct input *input)
+{
+	proc_ntc(st, input);
+	proc_buttons(st, input);
+	proc_machine(st);
+	proc_buzz(st);
 }
 
 void
-update_heater()
+output_leds(const struct state *st)
 {
-  if (state == HEATING || state == HOT || state == BREWING) {
-    int temp = analogRead(PIN_NTC);
-    if (temp < TEMP_MIN)
-      relay(PIN_HEAT, ON);
-    else if (temp > TEMP_MAX)
-      relay(PIN_HEAT, OFF);
-  } else {
-      relay(PIN_HEAT, OFF);
-  }
+	static int r = 0;
+	static int g = 0;
+
+	if (st->mstate == HEATING || st->mstate == COOLING) {
+		analogWrite(PIN_LED_RED, r);
+		setled(PIN_LED_GREEN, 0);
+		if (r >= 255)
+			r = 0;
+		else
+			r += 3;
+	} else if (st->mstate == HOT) {
+		setled(PIN_LED_RED, 0);
+		setled(PIN_LED_GREEN, 1);
+		r = 0;
+	} else if (st->mstate == BREWING) {
+		setled(PIN_LED_RED, 0);
+		analogWrite(PIN_LED_GREEN, g);
+		if (g >= 255)
+			g = 0;
+		else
+			g += 3;
+	} else {
+		setled(PIN_LED_RED, 0);
+		setled(PIN_LED_GREEN, 0);
+		r = 0;
+	}
 }
 
 void
-update_pump()
+output_heater(const struct state *st)
 {
-	if (state == BREWING) {
+	if (st->mstate == HEATING || st->mstate == HOT || st->mstate == BREWING) {
+		if (st->ntc_T < TEMP_MIN)
+			relay(PIN_HEAT, ON);
+		else if (st->ntc_T > TEMP_MAX)
+			relay(PIN_HEAT, OFF);
+	} else {
+		relay(PIN_HEAT, OFF);
+	}
+}
+
+void
+output_pump(const struct state *st)
+{
+	if (st->mstate == BREWING)
 		relay(PIN_PUMP, ON);
-  } else {
+	else
 		relay(PIN_PUMP, OFF);
-  }
 }
 
-void
-update_buzz()
+void do_output(const struct state *st)
 {
-  static unsigned long started = 0;
-
-  if (buzz_state == BUZZ_HEY) {
-    tone(PIN_BUZZ, 1500);
-    if (started == 0)
-      started = millis();
-    else if (millis() - started > 20) {
-      buzz_state = BUZZ_OFF;
-    }
-  } else if (buzz_state == BUZZ_STOP) {
-    tone(PIN_BUZZ, 220);
-  } else if (buzz_state == BUZZ_OFF) {
-    noTone(PIN_BUZZ);
-    started = 0;
-  }
+	output_leds(st);
+	output_heater(st);
 }
 
 void setup()
@@ -331,21 +337,18 @@ void setup()
 	pinMode(PIN_HEAT, OUTPUT);
 	pinMode(PIN_PUMP, OUTPUT);
 
-  /* Turn all relays off */
-  relay(PIN_HEAT, OFF);
-  relay(PIN_PUMP, OFF);
+	/* Turn all relays off */
+	relay(PIN_HEAT, OFF);
+	relay(PIN_PUMP, OFF);
 
 	Serial.println("Ready");
 }
 
 void loop()
 {
-	//Serial.println("Looping...");
-	update_buttons();
-	progress();
-  update_leds();
-  update_heater();
-  update_pump();
-  update_buzz();
-  delay(5);
+	do_input(&g_in);
+	do_proc(&g_st, &g_in);
+	do_output(&g_st);
+
+	delay(5);
 }

barista/ntc.c

@@ -0,0 +1,44 @@
+/* Copyright (c) 2025 Rodrigo Arias Mallo <rodarima@gmail.com>
+ * SPDX-License-Identifier: GPL-3.0-or-later */
+
+#include <math.h>
+
+/* Steinhart-Hart Thermistor Coefficients, used to convert resistance into
+ * temperature.
+ *
+ * The current NTC sensor has 102kOhm at 24C but I don't know the specific
+ * model, so the coefficients are computed for this NTC sensor instead:
+ * https://www.tme.eu/Document/f9d2f5e38227fc1c7d979e546ff51768/NTCM-100K-B3950.pdf
+ *
+ * The table seems to match what I would expect. Their R2 resistor is 6.8 kOhm,
+ * which yields a cuttof temperature of around 98.5 C at exactly half voltage
+ * (where the ADC would have more precision).
+ *
+ * In any case, we can calibrate the original NTC sensor by taking three
+ * temperature points. See:
+ * https://www.thinksrs.com/downloads/programs/therm%20calc/ntccalibrator/ntccalculator.html
+ */
+#define C1	0.7740577674e-3
+#define C2	2.073449619e-4
+#define C3	1.263502259e-7
+
+/* Return the temperature in celsisus */
+float
+ntc_temp(float R)
+{
+	/* Computing the log is slow, we may want to build a table */
+	float logR = log(R);
+	float T = (1.0 / (C1 + C2*logR + C3*logR*logR*logR));
+	float Tc = T - 273.15;
+	return Tc;
+}
+
+/* Return resistance in Ohms */
+float
+ntc_resistance(int Vo)
+{
+	float R1 = 10.0e3; /* Resistor for voltage divider */
+	float R2 = R1 * (1023.0 / (float)Vo - 1.0);
+
+	return R2;
+}

barista/ntc.h

@@ -0,0 +1,18 @@
+/* Copyright (c) 2025 Rodrigo Arias Mallo <rodarima@gmail.com>
+ * SPDX-License-Identifier: GPL-3.0-or-later */
+
+#ifndef BARISTA_NTC_H
+#define BARISTA_NTC_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+float ntc_resistance(int Vo);
+float ntc_temp(float omhs);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* BARISTA_NTC_H */

barista/pinout.h

@@ -0,0 +1,78 @@
+/* Copyright (c) 2025 Rodrigo Arias Mallo <rodarima@gmail.com>
+ * SPDX-License-Identifier: GPL-3.0-or-later */
+
+#ifndef BARISTA_PINOUT_H
+#define BARISTA_PINOUT_H
+
+#include <Arduino.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+/*
+ *                             ATmega328p
+ *                            +---------+
+ *  (PCINT14/RESET)      PC6 -|1  \_/ 28|- PC5 (ADC5/SCL/PCINT13)
+ *  (PCINT16/RXD)        PD0 -|2      27|- PC4 (ADC4/SDA/PCINT12)
+ *  (PCINT17/TXD)        PD1 -|3      26|- PC3 (ADC3/PCINT11)
+ *  (PCINT18/INT0)       PD2 -|4      25|- PC2 (ADC2/PCINT10)
+ *  (PCINT19/OC2B/INT1)  PD3 -|5      24|- PC1 (ADC1/PCINT9)
+ *  (PCINT20/XCK/T0)     PD4 -|6      23|- PC0 (ADC0/PCINT8)
+ *  VCC                      -|7      22|-     GND
+ *  GND                      -|8      21|-     AREF
+ *  (PCINT6/XTAL1/TOSC1) PB6 -|9      20|-     AVCC
+ *  (PCINT7/XTAL2/TOSC2) PB7 -|10     19|- PB5 (SCK/PCINT5)
+ *  (PCINT21/OC0B/T1)    PD5 -|11     18|- PB4 (MISO/PCINT4)
+ *  (PCINT22/OC0A/AIN0)  PD6 -|12     17|- PB3 (MOSI/OC2A/PCINT3)
+ *  (PCINT23/AIN1)       PD7 -|13     16|- PB2 (SS/OC1B/PCINT2)
+ *  (PCINT0/CLKO/ICP1)   PB0 -|14     15|- PB1 (OC1A/PCINT1)
+ *                            +---------+
+ *
+ * 
+ *         ATMEL ATMEGA8 & 168 / ARDUINO
+ *
+ *                          +-\/-+
+ *                    PC6  1|    |28  PC5 (AI 5)
+ *              (D 0) PD0  2|    |27  PC4 (AI 4)
+ *              (D 1) PD1  3|    |26  PC3 (AI 3)
+ *              (D 2) PD2  4|    |25  PC2 (AI 2)
+ *         PWM+ (D 3) PD3  5|    |24  PC1 (AI 1)
+ *              (D 4) PD4  6|    |23  PC0 (AI 0)
+ *                    VCC  7|    |22  GND
+ *                    GND  8|    |21  AREF
+ *                    PB6  9|    |20  AVCC
+ *                    PB7 10|    |19  PB5 (D 13)
+ *         PWM+ (D 5) PD5 11|    |18  PB4 (D 12)
+ *         PWM+ (D 6) PD6 12|    |17  PB3 (D 11) PWM
+ *              (D 7) PD7 13|    |16  PB2 (D 10) PWM
+ *              (D 8) PB0 14|    |15  PB1 (D 9) PWM
+ *                          +----+
+ *
+ *
+ */
+
+enum pinout {
+	/* Inputs */
+	PIN_POWER_ON  = 8,
+	PIN_HOT       = 9,
+	//PIN_FLOW      = PIN_D5,
+
+	/* Outputs */
+	PIN_LED_GREEN = 5,
+	PIN_LED_RED   = 6,
+	PIN_HEAT      = 7,
+	PIN_PUMP      = 12,
+	PIN_BUZZ      = 10,
+
+	/* Analog */
+	PIN_NTC       = PIN_A0,
+};
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* BARISTA_PINOUT_H */

barista/test/Makefile

@@ -0,0 +1 @@
+test_ntc: test_ntc.o ../ntc.c

barista/test/test_ntc.c

@@ -0,0 +1,15 @@
+#include <stdio.h>
+#include "ntc.h"
+
+int main(void)
+{
+	for (int i = 0; i <= 1023; i++) {
+		float R = ntc_resistance(i);
+		float T = ntc_temp(R);
+		if (T < 96.0 || T > 100.2)
+			continue;
+
+		printf("%6d  %12.1f Ohm  %12.1f C\n", i, R, T);
+	}
+	return 0;
+}