ir. ASM Steijlen

PhD student
Bioelectronics (BE), Department of Microelectronics

Themes: Lab-on-a-chip, Biosignal acquisition, conditioning and processing, Microsystem integration


  1. A New Approach for Monitoring Sweat Ammonia Levels Using a Ventilated Capsule
    Annemarijn Steijlen; Jeroen Bastemaijer; Robbert Nederhoff; Kasper Jansen; Paddy French; Andre Bossche;
    engineering proceedings,
    Volume 38, pp. 6, 2021. DOI:
    Keywords: ... sweat sensor; NH3; metal oxide gas sensor; ventilated capsule.

    Abstract: ... Ammonium levels in sweat can potentially be used to measure muscle fatigue and to diagnose particular metabolic myopathies. To research the potential use of ammonia in sweat as a biomarker, a new real-time monitoring system is developed. This system consists of a capsule that is placed at the skin and ventilated with dry air. A metal oxide gas sensor in the capsule detects the ammonia that is evaporated from sweat. The sensor system was built, and calibration experiments were performed. The sensors show good sensitivity from 27 mV/ppm to 1.1 mV/ppm in the desired measurement range of 1 to 30 ppm respectively. A temperature and humidity sensor are integrated to compensate for temperature and humidity effects on the NH3 sensor.

  2. Smart sensor tights: Movement tracking of the lower limbs in football
    Annemarijn Steijlen; Bastiaan Burgers; Erik Wilmes; Jeroen Bastemeijer; Bram Bastiaansen; Patrick French; Andre Bossche; Kaspar Jansen;
    Wearable technologies,
    Volume 2, 2021. DOI: 10.1017/wtc.2021.16
    Keywords: ... inertial measurement units, wearable sensors, football, movement tracking.

    Abstract: ... This article presents a novel smart sensor garment with integrated miniaturized inertial measurements units (IMUs) that can be used to monitor lower body kinematics during daily training activities, without the need of extensive technical assistance throughout the measurements. The smart sensor tights enclose five ultra-light sensor modules that measure linear accelerations, angular velocities, and the earth magnetic field in three directions. The modules are located at the pelvis, thighs, and shanks. The garment enables continuous measurement in the field at high sample rates (250 Hz) and the sensors have a large measurement range (32 g, 4,000°/s). They are read out by a central processing unit through an SPI bus, and connected to a centralized battery in the waistband. A fully functioning prototype was built to perform validation studies in a lab setting and in a field setting. In the lab validation study, the IMU data (converted to limb orientation data) were compared with the kinematic data of an optoelectronic measurement system and good validity (CMCs >0.8) was shown. In the field tests, participants experienced the tights as comfortable to wear and they did not feel restricted in their movements. These results show the potential of using the smart sensor tights on a regular base to derive lower limb kinematics in the field.

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Last updated: 28 Apr 2021

Annemarijn Steijlen