Flex WiFi Sensor

FlexSensor v3 -Blue

New features

The FlexSensor v3 shares all the same features as the previous versions bus with some cool additions.
  • Expansion Clone board of the poppular IotaWatttm . This is an open-hardware 14 channel WiFi connected electric power monitor. Using MCP3208 12 bit ADCs to sample voltage and current.
  • Battery power module, run your sensor of regular 1.5V batteries!
  • Updated Power-supply, connect even more sensors to your board.

Battery Module

You can now efficiently run the FlexSensor v3 with our custom made battery module.  

OpenEnergyMonitor IoTaWatt compatible module

IotaWatt is an open-hardware 14 channel WiFi connected electric power monitor. FlexSensor v3 shares the same hardware components as the original project and you can use the same software together with the expansion module. It’s based on the ESP8266 IoT platform using MCP3208 12 bit ADCs to sample AC voltage and current. IoTaWatt can log data locally to on-board SD card and post directly to Emoncms.org via WiFi



The original version released in January 2018.

Use Cases

Weather station

  • Display to show measurements (delivery of data to external source for graphs and analytics)
  • Indoor Temperature
  • Indoor Humidity
  • Outdoor Temperature
  • Pressure

Indoor Air quality

  • Temperature
  • Humidity
  • C02


  • PIR Motion sensor
  • 3x connectors for magnet switch -Door/Window

Electric power monitor

  • 14 x single-phase current sense (CT) channels
  • 1 x AC VRMS Channel
  • Compatible with multiple types of CT sensors and AC-AC voltage sensor adaptor
  • Local SD card logging
  • WiFi connected to post to Emoncms
  • Sample rate: 35-40 channels per second
  • Voltage (VRMS), Power (W) and Energy (kWh) logged to local SD card – every 5s
  • On-board Real-time-clock (RTC) with battery backup
  • Web-config interface


  • HVAC Control (Control your HeatPump remotely)
  • Measure Power consumption.
  • Temperature control, send commands to your heater
  • Boiler, measure temperatures on water

Home Control

  • Turn on lights when entering a room
  • Turn on scenes based on triggers
  • Remote control features. When you turn on the TV, dim the lights.