Restructure directory organization

src/atmega/Dockerfile

@@ -0,0 +1,18 @@
+FROM ubuntu:22.04
+
+RUN apt-get update && \
+    DEBIAN_FRONTEND=noninteractive apt-get install -y \
+    build-essential \
+    gcc-avr \
+    avrdude \
+    arduino-core-avr \
+    make \
+    && apt-get clean
+
+WORKDIR /usr/src/
+
+COPY . .
+
+RUN make all
+
+CMD ["./main"]

src/atmega/Makefile

@@ -0,0 +1,88 @@
+PROJECT = plant-manager
+
+MCU = atmega328p
+F_CPU = 16000000UL
+PROGRAMMER = usbasp
+
+ARDUINO_INSTALL_PATH = /usr/share/arduino
+ARDUINO_CORE_PATH = $(ARDUINO_INSTALL_PATH)/hardware/arduino/avr/cores/arduino
+ARDUINO_VARIANT_PATH = $(ARDUINO_INSTALL_PATH)/hardware/arduino/avr/variants/standard
+
+CC = avr-gcc
+CXX = avr-g++
+LD = $(CXX)
+OC = avr-objcopy
+AD = avrdude
+AR = avr-ar
+RM = rm -f
+
+BUILD_DIR = build
+OBJ_DIR = $(BUILD_DIR)/obj
+CORE_DIR = $(BUILD_DIR)/core
+
+CFLAGS = -Wall -Os -DF_CPU=$(F_CPU) -mmcu=$(MCU) -I$(ARDUINO_CORE_PATH) -I$(ARDUINO_VARIANT_PATH) -I.
+CXXFLAGS = $(CFLAGS) -fno-exceptions -fpermissive -std=gnu++11
+
+LDFLAGS = -Wall -Os -mmcu=$(MCU) -Wl,--gc-sections
+LIBS = -lm
+
+SRCS_CPP = main.cpp moisture.cpp
+HDRS = moisture.h config.h
+OBJS = $(addprefix $(OBJ_DIR)/, $(SRCS_CPP:.cpp=.o))
+
+CORE_C_SRCS = \
+	wiring.c \
+	wiring_analog.c \
+	wiring_digital.c \
+	hooks.c
+
+CORE_CPP_SRCS = \
+	abi.cpp \
+	new.cpp \
+	Print.cpp \
+	Stream.cpp \
+	HardwareSerial.cpp \
+	HardwareSerial0.cpp \
+	main.cpp
+
+CORE_SRCS = $(addprefix $(ARDUINO_CORE_PATH)/, $(CORE_C_SRCS) $(CORE_CPP_SRCS))
+CORE_OBJS = $(patsubst $(ARDUINO_CORE_PATH)/%.c,$(CORE_DIR)/%.o,$(filter %.c,$(CORE_SRCS))) \
+            $(patsubst $(ARDUINO_CORE_PATH)/%.cpp,$(CORE_DIR)/%.o,$(filter %.cpp,$(CORE_SRCS)))
+
+CORE_LIB = $(BUILD_DIR)/libcore.a
+
+EXEC = moisture
+ELF_TARGET = $(BUILD_DIR)/$(EXEC).elf
+TARGET = $(BUILD_DIR)/$(EXEC).hex
+
+all: $(TARGET)
+
+$(shell mkdir -p $(OBJ_DIR) $(CORE_DIR))
+
+$(ELF_TARGET): $(OBJS) $(CORE_LIB)
+	$(LD) $(LDFLAGS) $(OBJS) -L$(BUILD_DIR) -lcore $(LIBS) -o $@
+
+$(CORE_LIB): $(CORE_OBJS)
+	$(AR) rcs $@ $^
+
+# Compile your C++ files
+$(OBJ_DIR)/%.o: %.cpp $(HDRS) Makefile
+	$(CXX) $(CXXFLAGS) -c $< -o $@
+
+$(CORE_DIR)/%.o: $(ARDUINO_CORE_PATH)/%.c Makefile
+	$(CC) $(CFLAGS) -c $< -o $@
+
+$(CORE_DIR)/%.o: $(ARDUINO_CORE_PATH)/%.cpp Makefile
+	$(CXX) $(CXXFLAGS) -c $< -o $@
+
+$(TARGET): $(ELF_TARGET)
+	$(OC) -O ihex -R .eeprom $< $@
+
+flash: $(TARGET)
+	$(AD) -v -p $(MCU) -c $(PROGRAMMER) -D -U flash:w:$<:i
+
+clean:
+	$(RM) $(TARGET) $(ELF_TARGET) $(OBJS) $(CORE_OBJS) $(CORE_LIB)
+	$(RM) -r $(BUILD_DIR)
+
+.PHONY: all flash clean

src/atmega/config.h

@@ -0,0 +1,7 @@
+#ifndef CONFIG_H
+#define CONFIG_H
+
+#define MOISTURE_SENSOR_A0 A0
+#define SENSOR_READINGS 3
+
+#endif

src/atmega/main.cpp

@@ -0,0 +1,44 @@
+#include <Arduino.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <avr/sleep.h>
+#include <avr/wdt.h>
+#include <avr/interrupt.h>
+#include "moisture.h"
+
+ISR(WDT_vect) {
+    readSensors = true;
+}
+
+void watchdogs(void) {
+    cli();
+    MCUSR &= ~(1 << WDRF);
+    WDTCSR |= (1 << WDCE) | (1 << WDE);
+    WDTCSR = (1 << WDIE) | (1 << WDP3) | (1 << WDP0);
+    sei();
+}
+
+void enterSleep(void) {
+    set_sleep_mode(SLEEP_MODE_IDLE);
+    sleep_enable();
+    sleep_cpu();
+    sleep_disable();
+}
+
+void setup(void) {
+    Serial.begin(9600);
+    initMoistureSensor();
+    watchdogs();
+}
+
+void loop(void) {
+    if (readSensors) {
+        int16_t result = readMoisture();
+        if (result != -1) {
+            Serial.println(result);
+            readSensors = false;
+        }
+    }
+
+    enterSleep();
+}

src/atmega/moisture.cpp

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+#include <Arduino.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#include "moisture.h"
+#include "config.h"
+
+static int16_t moistureReadingSum = 0;
+static int8_t moistureReadingCount = 0;
+
+volatile bool readSensors = false;
+
+void initMoistureSensor(void) {
+    pinMode(MOISTURE_SENSOR_A0, INPUT);
+}
+
+void triggerSensorRead(void) {
+    readSensors = true;
+}
+
+int16_t readMoisture(void) {
+    if (!readSensors)
+        return -1;
+
+    moistureReadingSum += analogRead(MOISTURE_SENSOR_A0);
+    moistureReadingCount++;
+
+    //TODO: implement variance check (if over a certain variance discard measurements for this cicle)
+    if (moistureReadingCount >= SENSOR_READINGS) {
+        int16_t avg = moistureReadingSum / SENSOR_READINGS;
+        //Serial.println(avg);
+        moistureReadingSum = 0;
+        moistureReadingCount = 0;
+        readSensors = false;
+        return avg;
+    } else readSensors = true;
+
+    return -1;
+}

src/atmega/moisture.h

@@ -0,0 +1,13 @@
+#ifndef MOISTURE_H
+#define MOISTURE_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+void initMoistureSensor(void);
+int16_t readMoisture(void);
+void triggerSensorRead(void);
+
+extern volatile bool readSensors;
+
+#endif