Evaluate Sensor Beacon Applications with the reel board

reel board is an evaluation board based on the Nordic Semiconductor nRF52840 SoC with an integrated 2.4 GHz transceiver supporting Bluetooth Low Energy and IEEE 802.15.4. The board was developed by PHYTEC in cooperation with Zephyr Project for the "connect-up" Hackathon during Embedded Linux Conference (ELC) and OpenIoT Summit Europe on October 22-24, 2018.

The board has a built-in debug adapter based on the DAPLink interface firmware and NXP MK20DX128VFM5 SoC. It is optimized for low power applications and supports two power source configurations, battery and micro USB connector.

Schematics for the reel board can be found on PHYTEC's reel board website in the section "Download".

Features:

It is equipped with the Electrophoretic (electronic ink) Display (EPD), environmental (temperature, humidity, light, accelerometer) sensors, and Bluetooth connectivity making it easy to experiment and evaluate the Zephyr OS in these kinds of use cases:

• battery powered sensor node
• low-power, low-cost human-machine interface (HMI)
• for remote control and environmental sensor monitoring
• temperature and humidity monitor on your table
• product, name or price tag
• interactive badge for meetings and conferences

On the front of the board are RGB-LED, ADPS9960 and HDC1010 sensors, and Electrophoretic Display. The RGB-LED is controlled by the nRF52840 via GPIO pins. Display is controlled by the nRF52840 via SPI and 3 GPIOs.

On the back side of the board are all other components such as nRF52840, circuit for the Debug Adapter, On/Off and power source switch, battery holder, buttons and MMA8652 (accelerometer) sensor.

ADPS9960 is Digital Proximity, Ambient Light, RGB and Gesture sensor. HDC1010 is a digital humidity and temperature sensor. MMA8652 is a 12-bit Digital Accelerometer. All sensors are connected to the I2C bus and one GPIO pin each, which can be used as an interrupt source.

Expansion Connector:

The expansion connector has the same dimensions and similar pinout as the BBC MicroBit edge connector. The expansion components that are designed especially for the reel board are called link boards.

Sensor Beacon Firmware

There is the reel board software playground called "reel-board-parkour" on PHYTEC's profile "PHYTEC Messtechnik GmbH" at Github. You can find the "sensor_beacon" example, which is an out-of-tree project to be used with Zephyr. This example turns the reel board to a sensor beaon, exposing sensor measurements such as temperature, humidity and proximity.

Build the example and flash it to the reel board as described.

For receiving the sensor beacons you should use Linux with Bluez. You should see the values from the reel board in Linux with the Python "discovery" script under PHYTEC-Messtechnik GmbH/reel-board-parkour/sensor_beacon/utils.

Note:The reel board is only sending beacons when something is near to the proximity sensor (under the display on the top side of the reel board).

The beacon packets can be individualized according to requirements. This example shows temperature, humidity and the result of the proximity sensor.