> cat /diy/*.md

Flash your first ESP32

The ESP32 ships blank. This gets firmware onto it the easy way — straight from your web browser, no toolchain to install.

1. Plug the ESP32 into your computer with a data USB cable. (Charge-only cables are the #1 cause of "nothing happens" — if unsure, try another cable.)
2. If the board isn't detected, install the USB-serial driver. Most boards use CP2102 (Silicon Labs) or CH340 — search that chip name + your OS, install, reboot.
3. The no-install path: open web.esphome.io in Chrome/Edge, click Connect, pick the serial port, then Install to flash ESPHome. (Great if you're heading toward Home Assistant.)
4. Prefer Arduino? Install the Arduino IDE → Preferences → add the ESP32 boards URL → Boards Manager → install "esp32" → select ESP32 Dev Module and your port → upload the Blink example.
5. Confirm it worked: the onboard LED blinks, or ESPHome shows logs streaming. You're live.

Raspberry Pi headless setup (no monitor)

Set up a Raspberry Pi with no monitor, keyboard, or mouse — just your laptop and Wi-Fi. Perfect for servers, Pi-hole, or Home Assistant.

1. Download and install Raspberry Pi Imager from raspberrypi.com.
2. Insert the microSD. In Imager: choose your device, then Raspberry Pi OS Lite (64-bit) for a headless server (no desktop).
3. Click the gear / Edit Settings button — this is the key step. Set: hostname (e.g. pi.local), enable SSH, set a username + password, and enter your Wi-Fi SSID, password, and country.
4. Write the image, then pop the card into the Pi and power it on. Wait ~90 seconds for first boot.
5. From your computer's terminal, connect over SSH:

ssh # use the username + hostname you set
ssh pi@pi.local

6. Once in, update everything:

sudo apt update && sudo apt full-upgrade -y

Wi-Fi temperature & humidity sensor

Build a little sensor that reports temperature and humidity to your phone or Home Assistant over Wi-Fi. Uses an ESP32 and a DHT22 from the sensor kit.

1. DHT22 VCC → 3V3 on the ESP32.
2. DHT22 GND → GND.
3. DHT22 DATA → GPIO4. (Most DHT22 breakout boards include the needed pull-up resistor. If yours is a bare sensor, add a 10kΩ resistor between DATA and 3V3.)

Flash the ESP32 with ESPHome (see guide 01), then use this config:

esphome:
  name: room-sensor
esp32:
  board: esp32dev
wifi:
  ssid: "YOUR_WIFI"
  password: "YOUR_PASSWORD"
api:
logger:
ota:

sensor:
  - platform: dht
    model: DHT22
    pin: GPIO4
    temperature:
      name: "Room Temperature"
    humidity:
      name: "Room Humidity"
    update_interval: 30s

Save, install, then add the device in Home Assistant (it auto-discovers) to see live readings and build automations.

ESP32-CAM Wi-Fi security camera

Turn the tiny ESP32-CAM into a live-streaming Wi-Fi camera you can view in any browser. The catch: it has no USB port, so you flash it through a USB-serial adapter (or an ESP32-CAM-MB carrier board).

1. Wire the USB-TTL adapter: 5V→5V, GND→GND, TX→U0R, RX→U0T. Then jumper GPIO0 → GND to enter flashing mode.
2. In the Arduino IDE select board AI Thinker ESP32-CAM and the adapter's port.
3. Open File → Examples → ESP32 → Camera → CameraWebServer. Set your Wi-Fi SSID/password and make sure the CAMERA_MODEL_AI_THINKER line is enabled.
4. Click upload. When it says "Connecting…", tap the RST button on the CAM.
5. After upload: remove the GPIO0↔GND jumper and press RST. Open the Serial Monitor at 115200 to see the camera's IP address.
6. Browse to that IP on the same network → hit Start Stream. Mount it in the enclosure and you're done.

Prefer Home Assistant? Skip Arduino and flash an ESPHome config with the esp32_camera component instead.

ESPHome presence sensor for Home Assistant

A PIR sensor only sees motion — walk in, sit still, and the lights turn off. A mmWave radar (like the LD2410) detects that you're still present even when motionless. This build combines both for rock-solid room presence in Home Assistant.

1. LD2410 VCC → 5V, GND → GND.
2. LD2410 TX → GPIO4, RX → GPIO5 (UART).
3. PIR module (optional second signal): VCC → 5V, GND → GND, OUT → GPIO6.

esphome:
  name: presence-sensor
esp32:
  board: esp32-c3-devkitm-1
wifi:
  ssid: "YOUR_WIFI"
  password: "YOUR_PASSWORD"
api:
logger:
ota:

uart:
  tx_pin: GPIO5
  rx_pin: GPIO4
  baud_rate: 256000
  parity: NONE
  stop_bits: 1

ld2410:

binary_sensor:
  - platform: ld2410
    has_target:
      name: "Presence (radar)"
  - platform: gpio
    pin: GPIO6
    name: "Motion (PIR)"
    device_class: motion

Flash it, let Home Assistant auto-discover it, then use the Presence (radar) entity to keep lights on while you're sitting still — no more being plunged into darkness.