diff --git a/wiki/microcontroller.md b/wiki/microcontroller.md
new file mode 100644
index 0000000..d9ccad2
--- /dev/null
+++ b/wiki/microcontroller.md
@@ -0,0 +1,27 @@
+# Microcontroller
+
+Microcontroller are small computers on an integrated circuit.
+It contains a processor, memory and programmable in- and output.
+
+## ESP32
+
+The ESP32 is a cheap and low-energy microcontroller made by Espressif Systems.
+It features Wi-Fi and [Bluetooth](/wiki/bluetooth.md).
+
+### Flash Firmware on the ESP32 
+
+This section especially focusses on the ESP32S3 microcontroller.
+For other microcontroller of the ESP32-xx family the process should be similar.
+
+- Download [ESP RF Test Tool and Test Guide](https://www.espressif.com/en/support/download/other-tools)
+- Download [Firmware of ESP32S3](https://files.seeedstudio.com/wiki/SeeedStudio-XIAO-ESP32S3/res/XIAO-ESP32S3-firmware-20240814.zip)
+- Open `EspRFTestTool_vX.X_Manual.exe`
+  - Select the `ESP32S3` as `ChipType`
+  - Select the correct `COM` for your ESP
+  - Set the `BaudRate` to 115200
+  - Click `open`
+  - Click `Select Bin` and search for your ESP32S3 Firmware (probably named `xiao_esp32s3_firmware.bin` or similar)
+  - Left of the `Select Bin` button select `USB` and `Flash` for the two drop-down options
+  - Click `Load Bin`
+  - After the upload of the data a completion message should appear
+- The ESP32S3 is completely flashed