Pack accelerometer, gyroscope, magnetometer, barometer, temperature, and humidity sensing with BLE into the smallest possible board.
The Solution
nRF52832 SoC handles BLE and sensor polling over I²C/SPI. All sensors on the top side, RF section kept clear on the bottom with a ground plane cutout under the PCB antenna. USB-C for both charging and firmware programming. The matching network accounts for the proximity of multiple sensor ICs to the RF section.
Results
The client uses it as a drop-in module across three different product lines.
How six sensors fit in 18 × 22 mm
Sensors on one side, RF on the other. All the sensors sit on the top, the antenna keeps its ground cutout clear on the bottom, and the matching network allows for the sensor ICs close to the RF section.Matching for the board as built. With six sensor ICs packed close to the RF section, the antenna no longer presents the impedance its reference design assumes. A series inductor moves the point along a constant-resistance circle until it meets the unit conductance circle, and a shunt capacitor then carries it to the centre. The same two parts take the whole band below -10 dB.
Have a Similar Challenge?
High-density sensor integration with BLE is a core competency.
