While the ESP8266 lacks native Bluetooth, combining it with an HC-05 module or using Wi-Fi-based HID emulation gives you a functioning "wireless keyboard" solution. For true Bluetooth Low Energy (BLE) keyboard projects, upgrade to the ESP32 to save days of debugging.

A Bluetooth keyboard is a type of keyboard that connects to devices via Bluetooth technology. Bluetooth keyboards are widely used in various applications, including mobile devices, computers, and smart TVs. They offer a convenient and wireless way to input text and commands.

If you attempt the HC-05 method, you will hit these walls:

Use the ESP8266 to handle the complex key matrix scanning (it has more GPIO pins than the ESP32 in some configurations) and a tiny ESP32 (like the ESP32-C3) just for Bluetooth.

void setup() Serial.begin(115200); // Debug BT.begin(9600); // Default HC-05 baud rate pinMode(D1, INPUT_PULLUP); // Key 1 pinMode(D2, INPUT_PULLUP); // Key 2

When you hear the term "DIY Mechanical Keyboard," two microcontrollers typically come to mind: the (for its USB HID capabilities) and the ESP32 (for its built-in Bluetooth Classic and BLE). But what about the legendary, low-cost ESP8266 ?

if (digitalRead(D2) == LOW) BT.println("KEY_B_PRESSED"); delay(200);

void setup() Serial.begin(115200); bleKeyboard.begin();

The HC-05 is a Serial Port Profile (SPP) device. iPhones do not support SPP without a jailbreak. Android supports it, but you need an app like "Bluetooth Keyboard" to bridge the gap. You cannot use HC-05 as a native HID keyboard (like a Logitech dongle).