OPTIMI’s sensors

OPTIMI’s measurements

Within OPTIMI different wearable sensors have been constructed. In particular, ECG, activity and EEG. Additionally, a commercial microdialysis system was used to measure Cortisol.

These sensors have been used to monitor the following:

Body signals

  • A 3 electrode ECG for Heart rate wave form capture worn as a chest band similar to sports fitness devices
  • A 2 electrode EEG used on the forehead hairline, similar to a normal sports headband
  • A sub cutaneous sensor for Cortisol measurement, with wearable fraction collector.

Sensing of the user’s context

  1. Accelerometer in a wrist bracelet to measure arm activity for physical activity and sleep
  2. Accelerometer in an ankle bracelet to measure leg activity for physical activity and sleep
  3. Microphone in the home PC, for voice recording

Electrocardiogram (ECG)

EEG has been used to detect changes in behaviour, sleep anomalies and mental acuity that relate to depression. The following figures show the evolution from mockup, to prototype, to final design of OPTIMI ECG sensor and an example of use.

ECG evolution ECGexample

Activity (ACT)

The aim of development work on the ACT sensor was to design a miniature device with the ability not only to record pedometer type data, but to classify different types of motion. As above, we are showing the evolution of the sensor and an example of use.

ACT evolutionACT example


Electroencephalogram (EEG)

The aim of the design was to combine all the necessary functionality seen in other sensors into a small head band sensor. Below there is a picture of the final sensor design:



The measurement of the hormone cortisol is the gold standard biological indicator of the stress response. Cortisol measurement is well established and therefore it will be used in OPTIMI as a stress measurement biological marker.

In our project, the CORTISOL sampler is intended to collect minute samples of sub dermal body fluid in a long tubing cassette. Figure below shows the sampler:


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