The latest Wemos D1 Mini (4MB) V4.0.0 ESP8266 WIFI Internet of Things Development Board with PCB antenna.

Specifications:

• Dimensions: 1" x 1.3" x 0.063" (25.4mm x 33.0 x 1.6mm)
• 11 digital IO, interrupt/PWM/I2C/one-wire supported on 0.1" headers
• 1 analog input (3.2V max)
• USB-C connection with onboard CH340 serial IO chip
• LOLIN I2C Port
• Compatible with MicroPython, Arduino, nodemcu
• 3.3v device, can be powered by USB 5v
• 4MB Flash
• Clock Speed : 80/160MHz
• v4.0.0

More details here : https://docs.wemos.cc/en/latest/d1/d1_mini.html

These tiny IoT development boards are perfect for home automations projects. They can be flashed with the open source Tasmota firmware to use Home Automation applications of MQTT messages to control devices and read sensors.

The board comes with:

• Two 8 way pin headers
• Two 8 way sockets
• Two 8 way extension sockets

This board is compatible with my 4 Channel MOSFET Shield for Wemos D1 Mini ESP8266 and I use it in my home automation projects.

To read more about the projects I use these boards for read my blog : https://blog.mostlyrobots.net/

• Automatic Garden Watering to control four water solenoids connected to garden hoses.
• Immersion Heater Controller to control 2 high current relays to switch two 3kW hot water immersion heaters.
• Automatic plant Pot Watering to control a small peristaltic pump to water pot plants based on moisture reading from a capacitive moisture sensor.