Matthijs Kooijman
Eigenaar at Matthijs Kooijman IT
Randstad, Netherlands
Summary
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Rockstar🎓
Top SchoolMatthijs Kooijman is an experienced embedded systems engineer and founder with over 21 years delivering robust IoT and low-level software solutions from the Netherlands’ Randstad. As owner of Matthijs Kooijman IT since 2010 and an MSc in Embedded Computing Systems from Universiteit Twente, he specializes in Arduino/STM32 cores, LoRaWAN, and serial/USB subsystems while also contributing to major open-source projects like Django, FreeCAD and the Arduino ecosystem. His hands-on work spans firmware, hardware abstraction layers, library maintenance and CI/test improvements, showing a consistent focus on reliability, portability and efficient resource use. Matthijs also contributes strong documentation and tooling improvements (uWSGI docs, LLVM test-suite), reflecting an engineer who blends code craftsmanship with developer ergonomics. Notably, he maintained and evolved widely used Arduino libraries (including a long-running arduino-lmic LoRaWAN library) and has a track record of finding subtle bugs and edge-case fixes that improve real-world device stability.
21 years of coding experience
ir. / MSc, Technische informatica, Embedded computing systems, ir. / MSc, Technische informatica, Embedded computing systems at Universiteit Twente / Twente University
Dutch, English
Stackoverflow
2,707reputation
286kreached
34answers
1question
django
top-5%
Github Skills (106)
python10
lorawan10
testing10
c1110
spi10
perl10
c1710
gtk10
svg10
arduino-library10
3d10
lora10
database-management10
embedded10
iot-devkit10
Programming languages (32)
Github contributions (5)
matthijskooijman/arduino-lmic
Mar 2015 - Oct 2020
:warning: This library is deprecated, see the README for alternatives.
Role in this project:
Embedded Systems Engineer / IoT Developer
Embedded Systems Engineer / IoT DeveloperContributions:101 commits, 28 PRs, 47 pushes in 5 years 7 months
Contributions summary:Matthijs primarily contributed to the development of an Arduino library for the LoRaWAN protocol. Their work included the integration of the LMIC (LoRaMAC-in-C) library, adding a configuration file for compile-time settings, and implementing the hardware abstraction layer (HAL) for the Arduino environment. The user also added example sketches for raw TX/RX and LoRaWAN applications, while refactoring the code to support 32-bit architectures and improving interrupt handling.
teensyjavascriptarduino-librarybluepillarduino
arduino/ArduinoCore-avr
Apr 2013 - Sep 2020
The Official Arduino AVR core
Role in this project:Embedded Systems Engineer / IoT Developer
Embedded Systems Engineer / IoT DeveloperContributions:10 reviews, 99 commits, 9 PRs in 7 years 6 months
Contributions summary:Matthijs made several significant contributions to the Arduino AVR core, focusing on optimizing the HardwareSerial library. They refactored the code to use more efficient data types for buffer indices and reorganized the interrupt handling routines to improve performance and reduce code size. Furthermore, the user addressed potential lockup scenarios by adding checks for disabled interrupts and by implementing measures to prevent data loss, enhancing the reliability of serial communication. The user also implemented the necessary changes to support features such as timer1c and made several code improvements and refactorings.
avratmegaarduino
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