Implement sound module to handle audio alerts

README.md

@@ -4,7 +4,7 @@ Networked bedside clock utilising an ESP32-SOLO-1.
 
 ## Planned Features
 
-- [ ] Audio alerts
+- [x] Audio alerts
 - [x] 7 segment display
 - [x] WiFi networking
 - [x] Console for configuration

components/sound/CMakeLists.txt

@@ -0,0 +1,5 @@
+idf_component_register(
+  SRCS "sound.c"
+  INCLUDE_DIRS "."
+  REQUIRES console_wrapper driver esp_timer
+)

components/sound/sound.c

@@ -0,0 +1,129 @@
+/*
+ * SPDX-License-Identifier: AGPL-3.0-only
+ * Copyright (c) Camden Dixie O'Brien
+ */
+
+#include "sound.h"
+
+#include "console.h"
+
+#include "driver/dac.h"
+#include "esp_log.h"
+#include "esp_timer.h"
+#include <string.h>
+
+#define TAG "Sound"
+
+#define CHANNEL DAC_CHANNEL_1
+#define SIGNAL_FREQ CONFIG_ALERT_FREQ
+#define SIGNAL_AMPLITUDE CONFIG_ALERT_AMPLITUDE
+#define TOGGLE_PERIOD_US (1000 * CONFIG_ALERT_TOGGLE_PERIOD_MS)
+
+static esp_timer_handle_t timer;
+static bool signal_active;
+
+static void toggle_signal(void *arg)
+{
+	(void)arg;
+	if (signal_active) {
+		const esp_err_t error = dac_cw_generator_enable();
+		if (error != ESP_OK)
+			ESP_LOGE(TAG, "Error enabling signal: %04x", error);
+		else
+			signal_active = false;
+	} else {
+		const esp_err_t error = dac_cw_generator_disable();
+		if (error != ESP_OK)
+			ESP_LOGE(TAG, "Error disabling signal: %04x", error);
+		else
+			signal_active = true;
+	}
+}
+
+static int alert_command_func(int argc, char **argv)
+{
+	if (argc != 2) {
+		printf("Invalid number of arguments\n");
+		return 1;
+	} else if (strcmp(argv[1], "on") == 0) {
+		sound_alert_on();
+		return 0;
+	} else if (strcmp(argv[1], "off") == 0) {
+		sound_alert_off();
+		return 0;
+	} else {
+		printf("Invalid state %s\n", argv[1]);
+		return 1;
+	}
+}
+
+void sound_init()
+{
+	esp_err_t error;
+
+	dac_cw_config_t wave_gen_config = {
+		.en_ch = CHANNEL,
+		.scale = SIGNAL_AMPLITUDE,
+		.freq = SIGNAL_FREQ,
+	};
+	error = dac_cw_generator_config(&wave_gen_config);
+	if (error != ESP_OK) {
+		ESP_LOGE(TAG, "Error configuring wave generator: %04x", error);
+		return;
+	}
+
+	const esp_timer_create_args_t timer_config = {
+		.callback = &toggle_signal,
+		.arg = NULL,
+		.name = "signal toggle task",
+	};
+	error = esp_timer_create(&timer_config, &timer);
+	if (error != ESP_OK) {
+		ESP_LOGE(TAG, "Error creating toggle timer: %04x", error);
+		return;
+	}
+
+	console_register(
+	    "alert", "Set alert sound on and off", "alert <on|off>",
+	    alert_command_func);
+}
+
+void sound_alert_on()
+{
+	esp_err_t error;
+
+	error = dac_output_enable(CHANNEL);
+	if (error != ESP_OK) {
+		ESP_LOGE(TAG, "Error enabling DAC output: %04x", error);
+		return;
+	}
+
+	signal_active = false;
+	toggle_signal(NULL);
+
+	error = esp_timer_start_periodic(timer, TOGGLE_PERIOD_US);
+	if (error != ESP_OK) {
+		ESP_LOGE(TAG, "Error starting toggle timer: %04x", error);
+		return;
+	}
+}
+
+void sound_alert_off()
+{
+	esp_err_t error;
+
+	error = esp_timer_stop(timer);
+	if (error != ESP_OK) {
+		ESP_LOGE(TAG, "Error stopping toggle timer: %04x", error);
+		return;
+	}
+
+	if (signal_active)
+		toggle_signal(NULL);
+
+	error = dac_output_disable(CHANNEL);
+	if (error != ESP_OK) {
+		ESP_LOGE(TAG, "Error disabling DAC output: %04x", error);
+		return;
+	}
+}

components/sound/sound.h

@@ -0,0 +1,24 @@
+/*
+ * SPDX-License-Identifier: AGPL-3.0-only
+ * Copyright (c) Camden Dixie O'Brien
+ */
+
+#ifndef SOUND_H
+#define SOUND_H
+
+/**
+ * Initialize the sound subsystem.
+ */
+void sound_init(void);
+
+/**
+ * Turn the alert sound on.
+ */
+void sound_alert_on(void);
+
+/**
+ * Turn the alert sound off.
+ */
+void sound_alert_off(void);
+
+#endif

main/CMakeLists.txt

@@ -1,5 +1,5 @@
 idf_component_register(
   SRCS "main.c"
   INCLUDE_DIRS "."
-  REQUIRES console_wrapper display settings time wifi
+  REQUIRES console_wrapper display settings sound time wifi
 )

main/Kconfig.projbuild

@@ -16,6 +16,17 @@ menu "Bedside clock settings"
                  string "Default SNTP server domain"
                  default "pool.ntp.org"
      endmenu
+     menu "Alert sound options"
+          config ALERT_FREQ
+                 int "Frequency (in Hz) of the alert sound"
+                 default 300
+          config ALERT_AMPLITUDE
+                 int "Amplitude (0 to 255) of the alert sound"
+                 default 180
+          config ALERT_TOGGLE_PERIOD_MS
+                 int "Toggle period of alert sound in milliseconds"
+                 default 300
+     endmenu
      config WIFI_MAX_RETRIES
             int "Maximum number of times to retry connecting to WiFi network"
             default 10

main/main.c

@@ -6,6 +6,7 @@
 #include "console.h"
 #include "display.h"
 #include "settings.h"
+#include "sound.h"
 #include "time_manager.h"
 #include "wifi.h"
 
@@ -16,4 +17,5 @@ void app_main(void)
 	display_init();
 	wifi_init();
 	time_manager_init();
+	sound_init();
 }