In brief
An ordinary Bluetooth beacon tells a tracker in a vehicle: "I am nearby". Inside a building there is no tracker, so a different arrangement is needed: tags, anchors in the rooms and gateways, joined into a mesh network. In it every device passes data on along a chain, so few gateways are needed. The accuracy is by zone: a room, an aisle or a rack, not centimetres.
The problem sounds the same in a hospital and in a warehouse: the thing you need exists somewhere, but nobody knows exactly where. A nurse walks three floors looking for a free infusion pump. A picker goes to the bin the warehouse system points to and finds an empty space: the pallet was moved yesterday.
Outdoors a problem like that is solved by GPS. Inside a building there are no satellites, and a different approach is needed.
Why an ordinary Bluetooth beacon does not work here
BLE beacons have long been familiar in telematics. A beacon goes on a trailer, a container or a tool, and the tracker in the vehicle sees it over Bluetooth: "my trailer is where it should be", "that crate is in the body". The arrangement is simple and cheap, because all the work is done by the tracker, which is in the vehicle anyway and is already connected to a network.
Inside a building that arrangement falls short for two reasons.
First: there is nobody listening. There is no tracker in a hospital corridor. You could install receivers, but then you need a great many of them, and each one needs power and a network.
Second: the signal does not reach. The range of Bluetooth in a room with concrete walls, metal cabinets and racking is tens of metres at best. To cover a floor you would need so many receivers that the project would cost more than the problem.
How a mesh network is built
In a mesh network every device not only sends its own data but passes on other devices' data too. The data travels along a chain from neighbour to neighbour until it reaches a way out to the internet. So few expensive devices with power and a network connection are needed, and many cheap ones.
The system has three parts:
- Tags. They go on whatever moves: devices, tools, pallets, trolleys. They run on a built-in battery and need no wiring.
- Anchors. Fixed devices in known positions: one per ward, room, aisle or rack section. A tag hears the nearest of them, and that is how the system knows where it is.
- Gateways. They gather the data from the whole network and send it to a server. One or two per floor is usually enough.
One property matters a great deal: if an anchor fails, the network rebuilds the route through its neighbours. In a building where something is always being repaired or moved, that counts.
Teltonika builds such tags on the Wirepas Mesh protocol. According to the manufacturer, thousands of devices work in one network without interfering with one another.
What the accuracy is
This is the question on which expectations usually founder. A mesh system does not show a point on the plan to the centimetre. It shows a zone, and you set the size of the zone yourself by how densely you place the anchors.
- One anchor per room or aisle. The system will say "the pump is in the second floor treatment room", "the pallet is in the third aisle". That is enough to find something, and few anchors are needed.
- Anchors on rack uprights. The system will say "rack 3-14, top level". This is for expensive goods that are stored for a long time. The number of gateways does not grow — only anchors are added.
Both levels can be combined in one building: coarser and cheaper in the busy areas, more precise where valuables are kept.
Two kinds of tag
Teltonika's EYE Mesh line has two tags in the same 56.6 × 38 × 13 mm case weighing 19 g, with IP67 protection and an operating range from −20 to +60 °C.
- EYE Beacon Mesh transmits its identifier. It is tied to an inventory number, so the screen shows a particular device rather than "tag no. 4471".
- EYE Sensor Mesh adds temperature, humidity and movement. The tag itself knows whether it is moving or lying still, and it transmits more often on the move.
The CR2450 battery is built in and cannot be replaced. How long it lasts depends on how often the tag transmits: on the EYE Beacon Mesh the data sheet gives 2 years at one transmission every 5 minutes and 10 years at one an hour. When the battery runs out, the whole tag is replaced. The details are on the EYE Mesh page in the catalogue.
A hospital: what changes in practice
In a large clinic equipment is on the move constantly: a bed has gone off for a scan, a pump has been taken to intensive care, a wheelchair has been left by the lift in the next block. On paper everything belongs to a department; in practice the staff walk about and search.
With tags a nurse enters the type of equipment and sees a list: where each one is and which free one is nearest. Zones are set up separately: if a device leaves its department outside the agreed procedure, the person responsible gets a notification.
The benefit people rarely expect is the reports. The system keeps a history: where a device has been, how long it stood in each area, when it last moved. From that you can see how many pumps are genuinely in use, which beds have sat in the store for months and in which department equipment "goes missing" most often. For the people planning purchases that is figures instead of impressions. A detailed account is in the case study on finding medical equipment in a hospital.
A warehouse: what changes in practice
In a warehouse with thousands of storage locations a lost pallet is not a loss but half an hour of searching. In a single day goods are received, moved, replenished and picked dozens of times, and the paperwork cannot keep up.
Instead of walking to an empty bin, the picker looks at the system: the carton was moved two sections to the left yesterday. The shift supervisor sees that two of the five pallet trucks have stood in the corner of the returns area for three days while goods-in is complaining of a shortage.
One qualification matters here: the system does not replace the warehouse software. The software knows where goods ought to be; the tags show where they are. The benefit comes from comparing the two: stocktaking turns from a night-long count into a daily report on discrepancies. A detailed account is in the case study on finding pallets in a warehouse.
What not to expect
- Centimetre accuracy. The system shows a zone. It will help you find a device in a ward; it will not track movement within one large room.
- Working without infrastructure. A tag with no anchors and no gateways shows nothing. Buying "just the tags" and waiting for results will not work.
- An exact plan without a survey. Thick walls, lift shafts, metal racking and shielded rooms change the radio environment more than a drawing suggests. That is why one area is walked with test devices before buying for the whole building.
- Working in a freezer. The tags' operating range is from −20 to +60 °C. They are not meant for colder rooms.
Where to start
A sensible order is this:
- Choose an area for a pilot — one department or one warehouse zone, wherever the most expensive and most mobile equipment is.
- Walk it with test devices and firm up the anchor plan.
- Check the inventory records. If the numbers on file do not match reality, the tags will be tied to the wrong items and nobody will trust the system.
- Agree who receives the notifications and what they do about them.
- Extend the network once people are used to searching through the system rather than on foot.
We supply the whole kit: tags, anchors, gateways and configuration to the building's floor plan. If the client has vehicles of their own — ambulances, delivery vans, forklifts — we run those on the Wialon platform, so that there is one contractor for the premises and the roads alike. A short conversation about the task and the floor plan is a good place to begin.