In a world where everything becomes smarter and more connected the Internet of Things is on the rise. Due to increased demand on mobility and convenience battery-driven devices hold an increasingly important role in this. For engineers the development is challenging: it involves knowledge about connectivity, energy harvesting and management, software and sensor integration.
By Daniel Lehmann, R&D Engineer at Sensirion
In order to take full advantage of the performance and features of environmental sensors, e.g. humidity and temperature sensors, mechanical design rules need to be considered. Unbeneficial housing and PCB designs may cause unexpected temperature and humidity deviations and could increase the response time. Simply following four basic rules makes the integration easy and straightforward. From our experience, we recommend to take the mechanical integration of the sensors into account in a project as early as possible. The complexity of the integration will increase the later the housing is designed.
A. Most important the sensor has to be exposed to the ambient as much as possible and large openings in the housing should be used. This guarantees a fast system response and the influence of the housing can be minimized.
B. Furthermore, the sensor enclosure should be isolated from the other parts of the device. This will reduce offsets of the integrated system.
C. As third advice, the volume around the sensor, so called dead volume, needs to be minimized. This will result in a decreased response time.
D. Last but not least the sensor should be placed in an area without heating sources like Microcontrollers and ideally thermally decoupled. Otherwise, the heating effect of other components gives an offset to the sensor signal. If a mechanical solution is not sufficient to solve the issue, Sensirion also offers software based compensation for that.
More information regarding design-in can be found in the “Sensirion Design-In Guide”, which is available in the Downloadcenter of Sensirion’s website. The information in this guide should be partly transferable but not exhaustive for development of non-battery driven IoT devices and to the design-in of other environmental sensors.
Find more information about Sensirion’s new ultra-low power humidity sensor SHTC3 for battery-driven applications on www.sensirion.com/new-shtc3