Rest Assured is a smart thermometer that provides continuous, highly accurate body temperature data to a smart phone. Designed specifically for monitoring the temperature of infants and young children when they have a fever, it is simple and intuitive to use, providing peace of mind to parents.

Complete Solution



The key challenge was designing an accurate and comfortable device that could be worn by infants for long periods with a measurement accuracy of ± 0.2°C over the operating temperature. This required some out of the box thinking around the industrial design and electronic engineering to fit all the necessary components into a device with a total thickness of 6.28mm.

Another significant challenge was the RF performance as the location of the device significantly affected the performance of the antenna. The solution involved some ground-breaking approaches to PCB layout and antenna design.


Advisory Services:
In order to understand if Fidelis product was feasible we went through an extensive discovery phase to identify the gap in the market and if RestAssured would provide the right solution. We did this through market research, concept refinements, UX design, feasibility studies into battery technologies, RF performance and temperature accuracy, packaging and marketing material and managing ISO13485, FDA,TGA compliance programs.

Engineering Services:
RestAssured consists of 4 main components: The body worn Sensor, the adhesive patches, the charger and the smartphone application.
We handled both Hardware and embedded software design, wireless transmission of data via Bluetooth LE, 2.4GHz antenna design and tuning, customised battery technologies.

Manufacturing Services:
Through our key manufacturing partners we supported and ensured we mitigated risks that can cause issues for businesses during the manufacturing process. Including: Critical supplier audits (China), development of automated test systems, customised test jigs, production process validation and manufacturing activities with a Malaysian based contract manufacturer.

Key Areas

  • ISO13485, FDA & TGA compliance
  • Customised battery technology (flexible and thin)
  • Temperature sensing technology
  • Movement and Biosignal monitoring – Electical (EEG, EMG)
  • TENS Technology (Transcutaneous Electrical Nerve Stimulation)



The smart thermometer is a small device, not much bigger than a guitar pick. Specifically designed to be discreet and reliable, its triangular shape nestles comfortably into the axilla (armpit) to get the best possible temperature reading.

The device is held in position on the child by a low allergenic, disposable Adhesive Patch, the device can be easily worn for long periods without discomfort or adverse reaction.

The Charger provides a home for the Sensor and allows it to be easily recharged using any available USB power source and Smartphone Application.

The outcome of the discovery and feasibility work confirmed that the device was technically possible and ready for development.