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Add thermostat and heater control

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This commit is contained in:
Rodrigo Arias Mallo 2025-11-02 19:24:02 +01:00
parent 3ea6ff0e14
commit 678f16111b
5 changed files with 191 additions and 25 deletions
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56
barista/barista.ino
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@ -4,6 +4,8 @@
#include "ntc.h"
#include "overheat.h"
#include "led.h"
#include "heater.h"
#include "thermostat.h"
#include "pinout.h"
#include <avr/wdt.h>
@ -13,8 +15,7 @@ enum logic {
};
#define DEBOUNCE_TIME 20L /* ms */
#define TEMP_MIN 40.0f /* C */
#define TEMP_MAX 50.0f /* C */
#define TEMP_HOT 70.0f /* C */
#define LED_MIN_VALUE 0
@ -51,7 +52,6 @@ enum buzz_state {
BUZZ_ACTIVE,
};
int button_pin[MAX_BTN] = {
[BTN_ON] = PIN_POWER_ON,
[BTN_HOT] = PIN_HOT,
@ -94,6 +94,9 @@ struct state {
struct led red_led;
struct led green_led;
struct heater heater;
struct thermostat thermostat;
} g_st;
int read_input(int pin)
@ -191,27 +194,29 @@ void proc_buttons(struct state *state, const struct input *input)
int red_min = 50;
int red_state = red_min;
unsigned long brewing_max_time = 3000UL; /* 3 seconds */
unsigned long brewing_max_time = 30000UL; /* 30 seconds */
unsigned long cooling_time = 3000UL; /* 3 seconds */
unsigned long overheat_time = 10000UL; /* 10 seconds */
unsigned long max_heating_time = 60000UL; /* 60 seconds */
unsigned long max_idle_time = 10000UL; /* 10 seconds */
unsigned long max_idle_time = 120000UL; /* 120 seconds */
void proc_machine(struct state *st)
{
static unsigned long last_print_t = 0;
float temp = st->ntc_T;
int on = (st->btn[BTN_ON].state == RELEASED);
int brew_hot = (st->btn[BTN_HOT].state == PRESSED);
unsigned long t = millis();
Serial.print("t=");
Serial.print(millis());
Serial.print(" state=");
if (t - last_print_t > 100) {
Serial.print(t);
Serial.print(" ");
Serial.print(st->mstate);
Serial.print(" on=");
Serial.print(on);
Serial.print(" temp=");
Serial.print(temp);
Serial.println(" C");
Serial.print(" ");
Serial.println(temp);
last_print_t = t;
}
/* If the machine is overheating */
if (overheat_panic(&st->overheat)) {
@ -239,7 +244,7 @@ void proc_machine(struct state *st)
Serial.println("heating");
}
} else if (st->mstate == HEATING) {
if (temp > TEMP_MIN) {
if (temp > TEMP_HOT) {
st->mstate = HOT;
st->hot_t0 = millis();
st->buzz_state = BUZZ_HEY;
@ -349,14 +354,25 @@ output_leds(const struct state *st)
void
output_heater(const struct state *st)
{
if (st->mstate == HEATING || st->mstate == HOT || st->mstate == BREWING_HOT) {
if (st->ntc_T < TEMP_MIN)
unsigned long t = millis();
/* First configure thermostate */
if (st->mstate == HEATING || st->mstate == HOT || st->mstate == BREWING_HOT)
thermostat_set(&st->thermostat, TEMP_HOT);
else
thermostat_off(&st->thermostat);
/* Then update heater state from thermostate */
if (thermostat_state(&st->thermostat, st->ntc_T))
heater_on(&st->heater, t);
else
heater_off(&st->heater);
/* Then switch relays accordingly */
if (heater_state(&st->heater, t))
relay(PIN_HEAT, ON);
else if (st->ntc_T > TEMP_MAX)
else
relay(PIN_HEAT, OFF);
} else {
relay(PIN_HEAT, OFF);
}
}
void

47
barista/heater.c Normal file
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@ -0,0 +1,47 @@
/* Copyright (c) 2025 Rodrigo Arias Mallo <rodarima@gmail.com>
* SPDX-License-Identifier: GPL-3.0-or-later */
#include "heater.h"
#define HEATER_T_ON 500UL /* ms */
#define HEATER_T_OFF 5000UL /* ms */
void
heater_on(struct heater *h, unsigned long t_ms)
{
if (h->st == HEATER_ON)
return;
h->next_t = t_ms + HEATER_T_ON;
h->st = HEATER_ON;
h->turn_on = 1;
}
void
heater_off(struct heater *h)
{
h->st = HEATER_OFF;
h->turn_on = 0;
}
int
heater_state(struct heater *h, unsigned long t_ms)
{
if (h->st == HEATER_OFF)
return 0;
/* Switch state if current time exceeds time limit
* in the current state */
/* FIXME: Integer overflow can cause the heater to turn on forever */
if (t_ms > h->next_t) {
if (h->turn_on) {
h->turn_on = 0;
h->next_t = t_ms + HEATER_T_OFF;
} else {
h->turn_on = 1;
h->next_t = t_ms + HEATER_T_ON;
}
}
return h->turn_on;
}

30
barista/heater.h Normal file
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@ -0,0 +1,30 @@
/* Copyright (c) 2025 Rodrigo Arias Mallo <rodarima@gmail.com>
* SPDX-License-Identifier: GPL-3.0-or-later */
#ifndef BARISTA_HEATER_H
#define BARISTA_HEATER_H
#ifdef __cplusplus
extern "C" {
#endif
enum heater_state {
HEATER_OFF = 0,
HEATER_ON,
};
struct heater {
enum heater_state st;
int turn_on;
unsigned long next_t; /* in ms */
};
void heater_on(struct heater *h, unsigned long t_ms);
void heater_off(struct heater *h);
int heater_state(struct heater *h, unsigned long t_ms);
#ifdef __cplusplus
}
#endif
#endif /* BARISTA_HEATER_H */

41
barista/thermostat.c Normal file
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@ -0,0 +1,41 @@
/* Copyright (c) 2025 Rodrigo Arias Mallo <rodarima@gmail.com>
* SPDX-License-Identifier: GPL-3.0-or-later */
#include "thermostat.h"
#define DELTA_LOW 1.0
#define DELTA_HIGH 1.0
void
thermostat_set(struct thermostat *th, float temp_target)
{
if (th->st == THERMOSTAT_ON && th->temp_target == temp_target)
return;
th->st = THERMOSTAT_ON;
th->temp_target = temp_target;
th->temp_min = temp_target - DELTA_LOW;
th->temp_max = temp_target + DELTA_HIGH;
th->on = 1;
}
void
thermostat_off(struct thermostat *th)
{
th->st = THERMOSTAT_OFF;
th->on = 0;
}
int
thermostat_state(struct thermostat *th, float temp)
{
if (th->st == THERMOSTAT_OFF)
return 0;
if (th->on && temp > th->temp_max)
th->on = 0;
else if (!th->on && temp < th->temp_min)
th->on = 1;
return th->on;
}

32
barista/thermostat.h Normal file
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@ -0,0 +1,32 @@
/* Copyright (c) 2025 Rodrigo Arias Mallo <rodarima@gmail.com>
* SPDX-License-Identifier: GPL-3.0-or-later */
#ifndef BARISTA_THERMOSTAT_H
#define BARISTA_THERMOSTAT_H
#ifdef __cplusplus
extern "C" {
#endif
enum thermostat_state {
THERMOSTAT_OFF = 0,
THERMOSTAT_ON,
};
struct thermostat {
enum thermostat_state st;
float temp_target;
float temp_min;
float temp_max;
int on;
};
void thermostat_set(struct thermostat *th, float temp_target);
void thermostat_off(struct thermostat *th);
int thermostat_state(struct thermostat *th, float temp);
#ifdef __cplusplus
}
#endif
#endif /* BARISTA_THERMOSTAT_H */