LPS Mini – Local Positioning System in a very small form factor. Indoor navigation system with 10 cm precision. Higher precision can be achieved using on-board sensors for inertial navigation. Arduino Nano compatible (not a shield), except that some signals are used internally. Stripped down to a minimum, so an external USB/TTL-cable is needed for connectivity to a laptop.
LPS Mini is delivered with demo firmware that can measure distance between a tag and several anchors. Full source code (Arduino libraries and examples) and schematics are included for free. The user have full access to all radio settings. LPS Mini should thus be considered lab evaluation equipment and not a type approved commercial product.
- Outdoor range: Around 200-300m line of sight depending on your propagation environment.
- Indoor range: Around 30-50m depending on your walls.
- Update rate 1-10 Hz depending on your application.
- Accelerometer/Gyro/Compass: MPU-9250.
- Altimeter: MS5611-01BA03.
- Battery (optional, not included): Most small LiPo cells will do.
- LiPo Charger: MCP73812T-420I/OT.
- Solder pads for address setting and configuration.
- 8-bit ATMEGA328-MUR MCU.
- Crystal: Used to be 8 MHz, now upgraded to 12 MHz.
- Mates with TE Connectivity 5650712-1 to give easy access to all I/O (optional).
- 3.3V logic levels.
- Size: 29×28 mm.
- Weight without battery: 4g.
LPS Mini works either in tag or anchor mode. A tag measures distances to anchors in range and outputs accelerometer/gyro/compass/altimeter data and range readings via UART (3.3V levels). 3D localisation is then to be made in an external MCU, laptop or e.g. Raspberry Pi. Anchors work stand-alone. Depending on the size of your house three or more anchors are needed to give complete 3D navigation coverage. Data can also be sent via radio instead of UART.
Key differences compared to its bigger brother LPS:
- Stripped down to a minimum to get smaller size. Can not get much smaller without affecting antenna performance.
- Requires an adaptor to get the standard Arduino Nano footprint, but all I/O is available via a board edge connector.
- More advanced sensors: accelerometer/gyro/compass/altimeter instead of just accelerometer.
- Runs on 3.3V to enable operation from a single LiPo cell. As a consequence its I/O voltage is 3.3V instead of 5V and clock frequency 8 MHz instead of 16 MHz.
- Integrated LiPo charger.
We have had LPS prototypes up and running since February 2015. Large scale deployment was in place at Hayward Gallery in London from May to September 2015, where they were used to navigate robot beds:
LPS Mini evolved from LPS v1.1, so knowledge gained from LPS prototypes are built into LPS Mini.