Navigating through a subway is like a scavenger hunt: You have to look for clues on where to go next.
And GPS, though it works well above ground where satellites provide coordinates to find your bearings, can't help. Underground you can't get accurate coordinates to determine your location and choose a path. Multiple underground floors, thick walls and dozens of stairways mean a different solution is needed—one that:
- Has virtual guideposts that allow a person to get their bearings deep underground
- Is affordable so that hundreds of beacons can be installed for better accuracy
- Is a self-powered system that doesn’t require batteries
Underground in Tokyo: Navigating the Shibuya Station
Tokyo is attempting to solve the navigation problem in its Shibuya Station. The station, a maze with eight train lines, has more than a million people traveling its confusing pathways and platforms every day. To help those commuters, the city is implementing an ambitious project that uses augmented reality (AR), Bluetooth beacons and a mobile app to direct passengers to their destination.
Designing a Solution
Indoor navigation systems have to deal with two big challenges: accuracy and power. Wi-Fi-based systems can transmit signals farther, but beacons are more accurate with a smaller range. Installing lots of beacons creates a placement challenge, though: how will they get power?
The system uses energy harvesting systems to convert light into small amounts of power and store it to periodically power a transmitted signal. A Power Management IC is the core of this system, managing the storage and consolidation of the harvested energy to power a beacon.
A beacon is a Bluetooth Low Energy (BLE) device that periodically broadcasts its location to devices up to 300 feet away. Think of it as a lighthouse flashing its location for passing ships to determine their location. Cypress fits all this circuitry into a quarter-sized device.
How it works
The Shibuya Pedestrian Navi app from Boxyz guides commuters through Shibuya Station. The user’s location is first determined based on signals from nearby BLE beacons and the user is oriented by the direction of the camera phone’s camera aim. A route is calculated with beacons along the way as landmarks. Users see the path as arrows overlaid on the phone’s camera in the form of augmented reality.
A higher density of beacons makes such indoor navigation possible by lowering costs and delivering more precise locations from dozens of beacons scattered across the train station.
Wayfindr, a nonprofit organization that helps the vision impaired navigate independently, recently completed an inspiring project with Ustwo in the London Tube. The project also uses Bluetooth-assisted beacons to guide vision impaired people through the transportation system.
“Ultimately this innovative project is about giving our vision impaired customers the flexibility to travel with the same independence and spontaneity as everyone else,” said David Waboso, London Underground's Capital Programs Director, in a news release.
Finding your way around a subway overseas is confusing, but self-powered IoT beacons now make it manageable. Mobile apps with AR might even make it fun.
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