Tinycontrol
LK3.9

LK3.9 - a new generation of LAN Controller

LK3.9 is the next version of the popular series of LAN Controllers, equipped with a much faster processor and, as usual, a reliable Ethernet interface with active PoE. The device uses the same API as previous versions, making it perfect as a continuation of projects based on the v3.5 model.

However, it should be remembered that LK3.9 requires a dedicated version of the firmware, different from the one used in previous versions.

LK3.9 and LK4 are equivalent versions of devices with slightly different hardware capabilities.

Simple and convenient management

LK3.9 can be fully configured through an intuitive web interface, accessible via the built-in HTTP server.

Additionally, the device supports remote control using HTTP commands or - after initial setup - via MQTT protocol.

Interfaces

LK3.9 supports a variety of interfaces, allowing easy connection of many types of modules and sensors.

Logic inputs Analog inputs Transistor output Relay output

Interfaces 2

LK3.9 supports a variety of interfaces, allowing easy connection of many types of modules and sensors.

1-Wire: DS18B20 temperature sensors.

I2C: Temperature, humidity, pressure, particulate matter and CO2 sensors.

Outputs: 4 open collector outputs for controlling relays.

PWM outputs: 3 PWM outputs with relay control option.

Modbus *: Support for Modbus modules is available using a tHAT extension board or a Modbus RTU adapter.

Events

LK3.9 features an advanced event handling system that allows automatic actions to be triggered based on defined conditions.

It is possible to check two data sources simultaneously (e.g., sensors) and combine these conditions using a logic operator: AND, OR, NAND, NOR, or XOR.

In response to an event, you can:
  • control an OUT or PWM output,
  • send an email or SMS message,
  • send an SNMP trap, MQTT command, or HTTP request,
  • use virtual outputs to create more complex logic sequences.
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Scheduler

The scheduler allows automatic execution of actions at a defined time — as a one-time event at a specific hour, cyclical execution at a given time interval, or as part of a daily or weekly cycle.

Available actions include:
  • controlling OUT, PWM outputs or virtual variables (EVENT) – enabling control of connected devices,
  • resetting the energy counter,
  • activating or deactivating energy counting – allowing for separate usage tracking, e.g., for day and night tariffs.

Thanks to its flexibility, the scheduler is ideal for both home and industrial automation wherever precise time-based operation is required.

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Outputs

The OUT outputs in LK3.9 offer advanced configuration options such as automatic turn-off after a defined activation time (so-called output return), cyclic switching, delayed activation after power-up, and state memory for restoring output status after a restart or power loss.

Outputs can be controlled manually (via HTTP, MQTT, SMS) or through the scheduler and event system.

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PWM and Regulators

LK3.9 supports not only manual control of the PWM signal but also automatic operation using built-in regulators.

The following operating modes are available:
  • PID regulator – maintains a constant setpoint (e.g., temperature) by dynamically adjusting the PWM duty cycle.
  • Power regulator – stabilizes the power consumed by the load based on data from a power meter.
  • Voltage regulator – adjusts the load proportionally to the measured voltage in the AC network (single- or three-phase) to prevent exceeding the defined threshold.

A common use case is protecting PV installations from disconnection due to excessively high grid voltage.

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Modbus

LK3.9 enables reading data from various devices and sensors via the Modbus RTU (RS485) bus.

It offers ready-to-use profiles for popular energy meters and PV inverters, and also allows easy integration of other devices using the custom Modbus device configuration feature.

The acquired data can be used for automation, displayed in the web interface, or forwarded to an external server.

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Power and energy

LK3.9 provides convenient tools for monitoring real-time power and tracking energy consumption based on:
  • pulses from energy meters,
  • data read via Modbus,
  • direct current and voltage measurements.

It supports energy counter resets, enabling daily consumption tracking or separation by tariff. You can also automatically start or stop energy counting at specific times (e.g., using the scheduler), allowing precise monitoring of day and night tariff usage.

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mqtt.ats.pl service

Our proprietary solution complements the functionality of our devices, based on the MQTT protocol.

Access is free for self-use - all features are available with some limitations, but can be customized to your specific needs upon contact.

The service currently offers the following features:

  • Collecting data from the Lan Controller and presenting them on a chart or table, with the option of exporting data.
  • Defining reactions to incoming data with conditions regarding value, time. With their help, you can control one device depending on the readings from another device.
  • Defining tasks to be performed on selected days of the week at specific times (can be associated with reactions).
  • Viewing data from the supported devices and controlling it remotely using a website or a mobile application.