An asset management company EC-IS approached us with a request to integrate multiple wireless radio technologies into a small lock. Our solution is now used by Nordic Semiconductor to showcase products based on their Bluetooth 4.0 technology. We provided them with the complete software and hardware solution ready for demonstration to customers in only 40 days.
The challenge was to develop a very compact electronic module with the following functionalities: Bluetooth 4.0 Low Energy for communication with the smartphone, quad-band GSM with SIM on-chip for GPRS connection to the Internet, GPS location positioning, NFC (Near field communication) for user authorization, and smartphone connection, OLED display and keyboard input, Li-Ion battery charging via USB and energy harvesting, Accelerometer, EEPROM, motor driver and PCB board size of only 50 x 25 mm.
We had to integrate four different wireless technologies into a small form factor device that would fit inside the bicycle frame lock. GPRS connection was used for communication with the server. Bluetooth 4.0 was used for communication with the smartphone application. The user could open the lock directly from the app or with an NFC-based smart card. On top of that, a GNSS receiver was implemented to allow users to locate available bicycles via the app. The smart lock was powered from an internal Li-ion battery. We have implemented battery charging from the hub dynamo located on the front wheel. To fit four different antennas and other circuits inside a small enclosure, we designed the board on a semi-rigid flexible PCB.