'Top Considerations Before Starting Your IoT Design Project' (Part 2 of 4) by Symmetry Application Engineers Anuja Upale & Nimit Pradhan

This is part 2 of 4 of an article that originally appeared on www.embedded.com. Click here to read the full article.

by Symmetry Application Engineers Anuja Upale & Nimit Pradhan

Now that we’ve outlined the key questions to ask during the analysis phase, let’s take a look at a couple of different applications that demonstrate how asking these questions can help determine the right technologies for each unique situation.

Case Study #1 – Health Care

Our first case study is a customer that asked us for help in designing a Real Time Location System (RTLS) to ensure the safety of hospital staff and patients. The goal was three-fold: to tag infants for identification/parent matching; to tag children to ensure that they are protected from abduction and from wandering off; and to protect and locate staff so that security services or emergency notifications can reach them in the fastest possible time.

Each tag was to have a unique identifying number for patient identification, including bed location, room number, personal details, etc. The tagging system would be deployed within an adjustable bracelet for patients, or a badge for staff. For example, an infant’s ankle bracelet tag would be associated with a tag attached to its mother’s wrist at the time of birth for system identification. Staff would use hand-held devices to read identifications from all tags to identify a match. The user interface could be as simple as a green/red light.

The size parameter of the application was a huge variable for us as the customer wanted the device to be able to work in a wide variety of hospital sizes and setups. We advised the customer to survey different hospitals and gauge the approximate minimum and maximum dimensions of patient rooms, corridors, entrance halls, etc. The resulting estimate enabled us to plan out the infrastructure needed, including the number of anchors and tags to be used, the number of Wi-Fi access points/routers needed to ensure sufficient signal transmission throughout the facility, and the electrical specifications for the various components to be used in the wireless communication model.

We also needed to determine the ideal min/max range of signal transmission needed between each transmitter and receiver. Understanding range parameters is vital as it ensures that transmission signals reach the receivers with enough power to decode the signal efficiently and accurately. Identifying the type and number of devices required to supply long-range vs. short-range communication depends largely on the type of room. For example, empty rooms promote better signal reception than full rooms, so need fewer transmitters. Corridors, much like tunnels, have a natural tendency to carry signals in a specific direction and so need fewer transmitters than, say, a big hall with lots of furniture and people moving about. In the latter situation, more transmitters and receivers would be needed to overcome potential signal interference and distortion. Understanding all of various components, including low-noise amplifiers, power amplifiers, filters, frequencies, antenna specifications, etc., is necessary to determine the RF parameters for any wireless communication system.

Environment was another important consideration. Knowing that the end application would be a busy hospital, and that RF signals can quickly lose power and integrity when faced with interference, shadowing, reflection, refraction, etc., we ultimately selected an ultra-wide band chip technology that was proven to be immune to stray interference and the penetration of walls, furniture and bodies.

Given the unique security requirements of most hospitals, we also needed an economical and practical method to identify all persons and items of interest and their locations in real time. We knew the recommended technology, when integrated into an RTLS, would deliver a system capable of automatically managing the complex security requirements across a variety of deployment areas.

Integration turned out not to be an issue for us as the customer handled the integration with back end components directly. We did provide support on the chip level/module integration level, but otherwise we were able to redirect the flow of question to the chip manufacturer.

For IoT product information or technical support, contact Symmetry Electronics, an authorized distributor of industry leading wireless, audio/video and embedded chips, modules and dev/evaltools. www.symmetryelectroncis.com/contact-us or call (877) 466-9722.