Internet of Things

As side product of a new development we created some hardware which is quite different comparing to our main product line. Nevertheless this hardware is useful for different sophisticated applications, fully qualified and fully supported, so it offered as a second product line with full professional support.

Due to their extremely small size these boards are suitable for different green energy / IoT (Internet of Things) / IIoT (Industrial Internet of Things) applications. They can be used for productive and educational purposes, for professional applications and are also interesting for hobbyists and makers. Please find following some information about these products containing technical data and full specifications.

The IoT Leaf mainboard is a tiny ESP32-based device which can be used as highly flexible power supply, as embedded board or as a combination of both: it consists of a board which can be cut into two pieces resulting in two different devices or which can be used as one.

Both parts together come with an incredibly small size of about 5x4 cm.

The IoT Leaf Power Supply part can be used in many different scenarios and supports the following functions:

  • Power input via micro-USB or via 6V solar panel for green and self-contained IoT applications
  • Wide input voltage range from 3.75 V to 6.0 V
  • Supports LiPo battery cell with a charging current of up to 450 mA, automatic charging and deep discharge protection
  • Provides 3.3 V output with up to 500 mA current out of battery and/or power input
  • Can be extended to provide an other 5 V output which is covered by the deep discharge protection too (please see below)
  • Optional: hardware switch to turn off power and to stay in a lossless battery-charging-mode

The attached IoT Leaf Control Board part itself:

  • Bases on Espressif ESP32 dual-core SoC with 4 MByte flash memory, 520 kBytes SRAM and up to 240 MHz CPU-clock
  • Supports WiFi in client and access-point mode with on-board antenna
  • Provides Bluetooth and Bluetooth LE (BLE, low energy) with included antenna
  • Optional on-board Long Range Wide Area Network (LoRaWAN) support
  • Optional on-board NMEA GPS support
  • Integrated Hall-sensor and different analogue and digital interfaces
  • On-board low-power LED for basic signalling tasks
  • Can be operated with aboves power supply board or separated from it with an other 3.3 V power source
  • Easily programmable via 3.3 V serial interface out of ArduinoIDE using existing NodeMCU resources
  • Interfaces, outputs and layout can be modified according to your requirements (please contact us for details)

The 5V extension board can be connected to an existing IoT Leaf mainboard to provide an additional 5V output. This ouptut is fed from the same battery source and covered by the deep-discharge protection too.

The extension can be mounted on top of the IoT Leaf using the three-pin extension connector for electrical and mechanical connection and the screwhole for additional mechanical support and connection.

This extension board is open hardware licensed as Public Domain. EAGLE-files and BOM can be found in our public IoT-Leaf-GIT-repository at


IoT Leaf English manual containing hardware description as well as programming interface specification:iotleaf_manual.pdf

For a quotation, feature requests, suggestions or to order the board feel free to contact us!

Please note that HALaser Systems does not sell this board to private end users/consumers but only to companies and institutions. So requests from resellers and distributors are welcome!

The MPPT Leaf is a tiny, wide-range and multi-purpose power converter and power supply which can be used in many usage scenarios such as solar charge controller, battery-backed power supply, for self-contained applications or as wide-range voltage-converter. It supports the following features:

  • Power supply via solar cell using MPPT technology for highest efficiency
  • Wide input voltage range of 4,95 to 32 V from any power source
  • Charge controller for optional single-cell LiPo battery with up to 900 mA current
  • Deep discharge protection shuts down output voltage when battery is low
  • Stabilised and filtered 5V output with 800 mA maximum current
  • Extremely low size of about 49 x 20 mm


MPPT Leaf English manual containing full hardware description:mpptleaf_manual.pdf

A very first prototype of the MPPT Leaf solar charge controller is currently in production. Depending on the quality of this first drop and depending on the public interest we will start the production sooner or may be a bit later. For feature requests, suggestions, feedback and even to anounce your interest in this board, feel free to contact us!

Please note that HALaser Systems does not sell this board to private end users/consumers but only to companies and institutions. So requests from resellers and distributors are welcome!