Firefly brings the Wemos D1 Mini (ESP8266) together with accessible connections and a configurable web interface. It is designed for home automation, DIY electronics, educational projects, and data logging.

Hardware at a glance

Feature What it provides
128 × 64 OLED display Configurable readings from your panels
Screw terminals Accessible sensor and actuator connections
Two relays with output terminals Outputs for device control
IR receiver and buzzer Additional input and feedback options
I2C and OneWire connections Interfaces for compatible sensors
One analog input and four digital I/O pins Flexible inputs and outputs for projects

The board also includes push buttons and an SSD1306 I2C OLED display header. It runs an open firmware you can customize, and developers can load their own firmware.

Two-channel relay module mounted on a Firefly circuit board
A closer look at the two-channel relay module.

Configure through your browser

Firefly serves its interface directly from the ESP8266. Create panels for the inputs and outputs you want to work with, and save the configuration on the device.

  • Sensor calibration and averaging: Offset/factor or two-point calibration and optional averaging per panel.
  • Data logging: Record sensor readings to a file for later analysis.
  • Display configuration: Choose which panel values appear on the OLED screen.
  • Automation rules: IF/THEN rules over any panel or variable, e.g. IF temperature > 25 THEN heater = 0.
  • MQTT: Publish to any broker, with Home Assistant auto-discovery.
  • Variables: Define your own and computed variables, usable in rules and displays.
  • Backup / restore: Save or reload the whole configuration from the settings page.
Firefly OLED screen showing temperature and pressure readings with sensors connected
Sensor readings displayed directly on a Firefly board.

Sensors and controls

Firefly ships with ready-made panel drivers you can mix and match:

Panel driver What it does
Analog input Any 0–3.3V analog sensor on the A0 terminal
Digital input Buttons, switches and pulse sensors
DS18B20 OneWire temperature sensing
BMP180 I2C pressure and temperature
Ultrasonic (HC-SR04) Distance, tank level and clearance
Digital output Relays, LEDs and actuators
Servo 0–180° servo positioning (hardware PWM)
Inline water-flow sensor and electrically controlled valve connected with pipe fittings
A flow sensor and valve assembly for liquid-control experiments.

Automation

Automation rules use IF/THEN conditions over any panel or variable, with arithmetic, comparisons and logic — grouped into programs that can run steps, wait and set outputs. Home Assistant users get auto-discovered entities over MQTT for free.

CAD rendering of a liquid dispenser prototype with a reservoir, dispensing spout, and controller
A liquid-dispenser prototype concept, shown as a CAD rendering.

For makers, students, and developers

Start with the web interface to explore automation, or write your own firmware to experiment further. Wemos Mini ESP8266 shield PCBs and kits offer another route for students and DIY enthusiasts who want to assemble and learn.

Looking for the smaller board? See Firefly Mini — same firmware, compact footprint.\n\nAsk about Firefly, PCBs, and kits →