Added starter example project.

.gitignore

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+bin/

.vscode/c_cpp_properties.json

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+{
+    "configurations": [
+        {
+            "name": "AVR",
+            "includePath": [
+                "${workspaceFolder}/**",
+                "/lib/avr/include/**"
+            ],
+            "defines": [],
+            "compilerPath": "/usr/bin/avr-gcc",
+            "cStandard": "gnu17",
+            "cppStandard": "gnu++14",
+            "intelliSenseMode": "gcc-avr",
+            "configurationProvider": "ms-vscode.makefile-tools"
+        }
+    ],
+    "version": 4
+}

Makefile

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+all: clean build
+
+clean:
+	rm -rf bin/
+
+flash: build
+	avrdude -c arduino -p atmega328p -P /dev/ttyUSB0 -b115200 -U flash:w:bin/gympal.hex:i
+
+build: gympal.hex
+
+gympal.hex: src/gympal.c bin
+	avr-gcc -Wall -Os -DF_CPU=16000000UL -mmcu=atmega328p -c src/gympal.c -o bin/gympal.o
+	avr-gcc -Os -mmcu=atmega328p -o bin/gympal.elf bin/gympal.o
+	avr-objcopy -O ihex -R .eeprom bin/gympal.elf bin/gympal.hex
+
+bin:
+	mkdir bin

README.md

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 # GymPal
 A simple device for recording gym sessions, using AVR.
+
+## Development
+The software for this system is developed in C, using [avr-libc](https://www.nongnu.org/avr-libc/), and the build toolchain is managed by make, using [avr-gcc](https://linux.die.net/man/1/avr-gcc) and [avr-dude](https://github.com/avrdudes/avrdude) to upload firmware to the Atmega328p microcontroller.
+
+To compile the firmware, you can run `make`.
+
+To upload the firmware to an Arduino, run `make flash`.
+
+### Helpful Links
+The following links are helpful for learning how to program an AVR-based microcontroller.
+
+- [avr-libc Homepage](https://www.nongnu.org/avr-libc/)
+- [avr-libc Library Reference](https://www.nongnu.org/avr-libc/user-manual/modules.html)
+- [avrdude Firmware Uploader](https://github.com/avrdudes/avrdude)

src/gympal.c

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+#include <avr/io.h>
+#include <util/delay.h>
+
+int main() {
+    // Pin 12 == Port B4, aka 4th bit on the B register.
+    // Set pin 12 as output.
+    DDRB = 1 << PORTB4;
+    // Set pin 12 as HIGH.
+    PORTB = 1 << PORTB4;
+    // Delay for 1 second.
+    _delay_ms(1000.0);
+    // Set pin 12 as LOW.
+    PORTB = 0 << PORTB4;
+    return 0;
+}