Wi-Fi LED Fairy Light Controller with ESP8266

A DIY Wi-Fi-controlled 5 V switcher for USB LED fairy lights, built around an ESP-12F module running Tasmota firmware. Powered by a battery bank, it lets you toggle garden lights remotely from your phone — no 230 V wiring outdoors and no freezing walks to the power outlet.

The lights

"USB Fairy Lights" or "USB String Lights" — 10 m / 100 LEDs, available from China for under ~$3. They are 5 V USB-powered and weather-proof (except the USB connector).

The 100-LED circuit with 5.1 Ohm series resistor — consumes ~1.8 W at 5 V.

Close-up of a single LED — brightness difference between first and last LED is barely noticeable from a distance.

The ESP-12F 5 V switcher

An ESP-12F module with a MOSFET switches the USB 5 V supply to the LED string. Running Tasmota firmware, it connects to your Wi-Fi network and can be controlled from a phone or any MQTT/HTTP client.

Complete setup — battery bank, ESP-12F switcher, and LED fairy lights.

With Tasmota's default configuration (no deep sleep), the battery bank needs recharging every few days. A larger battery and ESP8266 deep sleep could extend runtime to weeks.

Assembly

Before starting, ensure the ESP-12F module is pre-programmed with Tasmota (or any OTA-capable firmware). See ESP-12F programming guide for first-time flashing.

Items needed:

Step 1:

Step 2:

Step 3:

Step 4:

Step 5:

Step 6:

Step 7:

Step 8:

Step 9:

Final assembly:

Completed setup — ESP-12F switcher between battery bank and LED fairy lights.

Related posts

• Pogo-Pin Programming Dock for ESP-12F Modules
• Build a $2 IoT/MQTT Node with a Bare ESP-12F
• $20 Pocket Router as Domoticz Smart Home Gateway

$20 Pocket Router as Domoticz Smart Home Gateway

A custom OpenWrt firmware (autom8box) that packs router + Domoticz server + MQTT broker into an all-in-one home automation gateway running on a ~$20 off-the-shelf GL-MT300N-V2 pocket router.

System overview: GL-MT300N-V2 running autom8box firmware as Wi-Fi AP, MQTT broker, and Domoticz server.

The problem

Wi-Fi based home automation products are cheaper than Zigbee or Z-Wave, but they typically require internet connectivity. Letting cloud servers control your home devices is not ideal — internet should be optional, not mandatory.

Thanks to the open-source community (Tasmota, ESPurna, etc.) for helping jailbreak devices like Sonoff, Blitzwolf, and Teckin. But jailbreaking solves only part of the problem — you still need a home automation gateway: Wi-Fi access point + MQTT broker + automation server (Domoticz, OpenHAB, etc.).

What autom8box provides

• Wi-Fi access point — dedicated network for your IoT devices
• DHCP and DNS server — automatic network configuration
• MQTT broker (Mosquitto) — message bus for IoT devices
• Domoticz — home automation dashboard and rules engine

GL-MT300N-V2 (~$20) — compact pocket router running the autom8box firmware.

Limitations: Limited Wi-Fi range and a reduced set of Domoticz plugins due to the 16 MB flash limit. But it's a good starting point for low-budget home automation.

Flashing steps

Step 1 — Download autom8box-mt300nv2.bin.

Step 2 — Power on the GL-MT300N-V2 and wait for its SSID to appear (shown as GL-MT300N-V2-xxx).

OEM SSID appearing in the Wi-Fi list.

Step 3 — Connect to the SSID. When prompted for a password, enter goodlife (printed on the device's back sticker).

Enter the default Wi-Fi password.

Step 4 — Once connected, you should see the confirmation message:

Successfully connected to the router.

Step 5 — Open a browser and navigate to:
http://192.168.8.1/cgi-bin/luci/admin/system/flashops

LuCI login — leave the password box empty and click "Login".

Step 6 — In the firmware update section, uncheck "Keep settings", choose autom8box-mt300nv2.bin, then click "Flash Image".

Firmware upload — uncheck "Keep settings" and select the autom8box binary.

File selected — ready to flash.

Step 7 — Click "Proceed" to confirm:

Confirm flashing — click "Proceed".

Step 8 — Wait about 2 minutes for the flash to complete:

Firmware flashing in progress — wait for the device to reboot.

Step 9 — After reboot, a new SSID autom8box will appear. Connect with password goodlife.

The new autom8box SSID is now visible.

Step 10 — Open http://192.168.8.1:8080 in your browser — Domoticz is ready:

Domoticz home automation dashboard — running entirely on the pocket router.

Post-setup security

SSH credentials: user root, password goodlife

Change root password:

passwd root

Change Wi-Fi password:

uci set wireless.default_radio0.key=my-new-password
uci commit wireless
wifi

Change SSID:

uci set wireless.default_radio0.ssid=my-new-ssid
uci commit wireless
wifi

Important: autom8box does not auto-save the Domoticz database. After configuring your devices, SSH in and run reboot — during reboot the database is saved from RAM to the persistent partition. A hard power cut without rebooting may lose your configuration.

SOURCE CODE

github.com/hackboxguy/lede-a5v11 — build instructions and sources

autom8box-mt300nv2.bin — pre-built firmware image

Related posts

• Build a $2 IoT/MQTT Node with a Bare ESP-12F
• Vendor-Neutral Zigbee Gateway with Raspberry Pi
• Alexa Controls Domoticz via Philips Hue Emulator
• Remote Home Access with a 5-Euro Pocket Router

Build a $2 IoT/MQTT Node with a Bare ESP-12F

How to use a bare ESP-12F module as a standalone IoT/MQTT node — powered directly from a USB charger with just a handful of passive components, no base board required. Total cost: under $2.

Finished board — ESP-12F module with USB connector, ready to plug into any 5V charger.

Items needed

Prices based on AliExpress at the time of writing:

• 1x ESP-12F module (pre-programmed with Tasmota firmware)
• 1x 10k SMD resistor
• 1x 10k through-hole resistor
• 2x 4001 SMD diode
• 1x USB male connector (PCB mount, SMD)

Schematic

Wiring diagram — USB 5V stepped down through two diodes to ~3.6V for the ESP-12F.

Board preparation

Step 1 — Ensure the ESP-12F module is programmed with Tasmota firmware. See the ESP-12F programming post for details.

Step 2 — Mount a 10k SMD resistor between the GND and IO15 pads of the ESP-12F module.

10k SMD resistor soldered between GND and IO15 pads.

Step 3 — Mount a 10k through-hole resistor between the VCC and EN pads of the ESP-12F module.

10k through-hole resistor connecting VCC to EN (chip enable).

Another angle showing the VCC–EN pull-up resistor.

Step 4 — Stick a piece of insulation tape on the right side of the ESP-12F module so the USB connector doesn't short any pads.

Insulation tape prevents shorts between the USB connector and ESP pads.

Step 5 — Place the USB connector as shown below. The SMD pins of the USB connector should sit over the insulation tape.

USB connector positioned over the insulation tape.

Step 6 — On the back side, fix the USB connector to the ESP-12F using hot glue. Don't apply hot glue on the SMD pin side yet — that comes later.

Hot glue secures the USB connector on the back side.

Step 7 — Solder two SMD diodes in series between the + line of the USB connector and the VCC pad of the ESP-12F module.

Two 4001 diodes in series drop 5V USB to ~3.6V for the ESP-12F.

Step 8 — Connect the − line of the USB connector to the GND pad of the ESP-12F module.

USB ground connected to the ESP-12F GND pad.

Step 9 — Apply hot glue on both sides of the USB connector and ESP-12F for stability.

Hot glue on both sides for mechanical strength.

Completed board — ready for testing.

Testing

Step 10 — Power the board with a 5V USB charger and look for an open Wi-Fi SSID named sonoff-NNNN.

Step 11 — Connect to the SSID and follow the standard Tasmota generic module configuration.

Your $2 IoT/MQTT node is ready. Plug it into any USB charger, configure Tasmota to connect to your MQTT broker, and start automating.

Related posts

• Pogo-Pin Programming Dock for ESP-12F Modules
• Wi-Fi LED Fairy Light Controller with ESP8266
• $20 Pocket Router as Domoticz Smart Home Gateway