The research proposes a prototype for an indoor real-time location system (RTLS) using Bluetooth Low-Energy devices for tracking medical equipment. The ESP32 microcontroller acts as a receiver node in each room, collecting the MAC address from the HM-10 beacon attached to the equipment and sending this data to a web server.
To calculate the distance between the node and the beacon, the Received Signal Strength value is filtered to reduce noise. Tests show that the average distance error between the beacon and node is roughly 3 metres and and the maximum time to update the location from node to node is less than 15 seconds.
This solution offers precise timestamps and location information based on distance, range, duration or direction.
Due to the pandemic, hospitals and care facilities have been experiencing greater patient numbers leading to pressures to accelerate digital transformation to increase efficiency. At BeaconZone, these are the main reasons customers have been using locating systems:
To save time searching for equipment, particularly highly mobile equipment such as wheelchairs
To monitor the location and temperature of medicines
To monitor the location of hospital porters
To track the location of vulnerable patients
To audit the visiting of care givers to patients
However, there are many more areas suitable for increasing efficiency and safety:
Tracking expensive assets such as beds and medical devices
Tracking rental/borrowed equipment to ensure they are returned on time to avoid unintended costs
Staff distress SOS for increased safety
Hygiene management, for example, on hand washing stations
Inventory counts and stock checks
Analysis of workflows to detect choke points and streamline processes
Production of key metrics such as time being spent with patients, patient throughput and wait times
Time saved improving the above activities leads to more time being spent with patients and hence potentially saved lives.
Here are some considerations if you are comparing solutions:
Tag costs – Prefer commodity rather than proprietary hardware to reduce costs and allow 2nd sourcing to reduce future risk
Real time – Prefer systems that detect continuously over those that rely on error-prone manual scanning
Scalable – Prefer software systems that will scale financially, particularly in large hospitals
Ongoing costs – Prefer systems that have known future system costs – ideally with a one-off licence rather than varying subscription.
One final tip. It’s our experience that healthcare providers under-estimate the human element in attempting to implement new systems. There are often internal problems as to who will be responsible for a) purchasing, b) installing and c) running new systems. Work these out and agree up-front before embarking on these transformative changes so as to prevent your project becoming blocked.
James Bayliss, a final year industrial design student at Loughborough University, has designed a smart mobility aid that uses beacons. It’s allows people with dementia to live safely in their own home for longer.
The system, called ‘AIDE’, comprises of a walking stick that works with Bluetooth beacons situated around the home.
It tracks the person’s movement and uses machine learning software to detect behaviours and actions that are out of the ordinary. The system also provides reminders to the person to help re-orient them if they have a confused episode.
Wake Up Radio (WUR) uses a very low power device that senses a radio signal to switch other devices, in this case a Bluetooth LE transmitter. A AS3930 WUR senses a signal in the range 110-150 kHz and switches a Texas Instruments Bluetooth CC2640R2 LaunchPad board.
The idea is that usually Bluetooth LE advertises every say 100ms to 1000ms and this is wasteful on battery power if the advertising is only needed for short periods of time. The paper assesses the feasibility of using WUR to turn advertising on and off to save battery power. While this is in in the context of wearables, the authors don’t mention much more regarding what might switch the beacons to advertise, other than:
The transmitter of this wake-up signal, which is usually a less restricted device, might be integrated with the communication infrastructure or deployed as an independent system element
The authors later mention healthcare so perhaps wearable beacons might only transmit when needed in particular areas.
It’s also mentioned that WUR can mitigate against the problem of interference when many Bluetooth devices advertise at the same time. This problem is rare and requires a very large number of devices. The authors later mention healthcare but this is unlikely to be a problem. A warehouse with thousands of assets might be a more realistic scenario. In this case, you could envisage wanting a Bluetooth beacon only transmitting when invited to do so.
The paper has some useful charts showing usual Bluetooth power use over time (without WUR):
You can see the periodic advertising which isn’t regular due to the 10ms long pseudo-random delay between advertisements. This is the part of the Bluetooth standard that helps ensure two device that collide usually don’t do so the next time they advertise. In between advertising, the power use a very low 0.3 µW.
The paper shows that energy consumption of the system as a function of the number of wake-ups in a period of time and the maximum application-level latency:
The paper concludes that the WUR approach can be more energy efficient when the desired latency for data delivery is below 2.11s. Even though the consumption of the WUR is low, it unfortunately exceeds the level of a BLE only system sleep mode by almost two orders of magnitude.
In our opinion the researchers are trying to improve on something that is already very low power. In between advertising, power use is extremely low. A CR2477 battery in a Bluetooth wearable can advertise periodically for up to 3 years. Also, for the wearable scenario, it’s more normal to use a low power accelerometer to only have the wearable transmit when moving. This way the battery lasts an extremely long time that’s limited more by the physical lifetime of the battery (5 to 10 years) rather than battery consumption.
The time saving is incredible… there are thousands of more things the hospital would want to track in the future
Toby Roberts, Putney Hospital Associate Director of Information
At BeaconZone we have customers using beacons to track wheelchairs, porters carrying medicines and the location of vulnerable Alzheimer’s patients.
We have found the main problem with introducing new technology into hospitals is lack of funding. Anything outside purchasing for the frontline is de-prioritised. Health providers tend to have have blinkered priorities that work against efficiency and cost savings.
If you think about having three key nurses and a couple of health care assistants running around the hospital for half an hour to find a piece of equipment, even if you just add up their hourly rate, let alone the increase in service quality, it’s really quite an easy equation to justify
Toby Roberts, Putney Hospital Associate Director of Information
Russ Sharer, Vice-President of Global Marketing for Fulham, a manufacturer of energy-efficient lighting sub-systems has written an article in Health Estate Journal (pdf) on the use of iBeacons in healthcare.
Russ says it’s often difficult to find life saving equipment in hospitals and many organisations have to compensate by purchasing more equipment than they need. However, in use, equipment still gets misplaced, usually just at the critical time it is needed. He explains how the use of Bluetooth beacons and mesh can solve this problem. The article provides a great introduction to iBeacons and some issues such as the affect of frequency of transmission on battery life.
While the article mentions Bluetooth Mesh and iBeacons, these specific technologies don’t always have to be used. Gateways can be used instead of mesh to allow greater throughput of data. Also, any beacons, not just iBeacons, can be used as it’s usually the MAC address of the beacon that’s used for identification purposes. Using sensor beacons allows further scenarios, for example, monitoring the temperature of expensive medicines.
There are also many more scenarios for the use of beacons in healthcare than are mentioned in the article. Our beacons are being using to track hundreds of dementia patients. We have also been involved in a project to use beacons for navigation in large hospitals. Once there’s a network of beacons in a hospital, it’s possible to add lots of widely varying solutions.