68 lines
3.1 KiB
Plaintext
68 lines
3.1 KiB
Plaintext
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Title: Environmental Sensing
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Description:
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This sample is a simple environmental sensing service for the Arduino 101 board.
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The ARC application collects temperature, humidity and pressure data from
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a set of sensors connected to the Arduino 101 and sends it to the x86 core
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through IPM. The colected sensor data is also displayed by the ARC core on
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a Grove LCD.
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The x86 application exposes the received sensor data as a simple Bluetooth
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Environmental Sensing Service.
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Sensor wiring:
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The sample uses the HDC1008 sensor for temperature and humidity measurement, and
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the BMP280 sensor for pressure measurement. This section describes how to wire
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these sensors to the Arduino 101 board.
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Both sensors operate at 3.3V and use I2C to comunicate with the Arduino. On the
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Arduino 101, the I2C data pin (SDA) is exposed as pin A4 (on the ANALOG IN header)
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and the I2C clock pin (SCL) as pin A5 (also on the ANALOG IN header). Since the
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Arduino 101 doesn't have internal pull-up resitors, these need to be added externally
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when connecting SCL and SDA to the sensors.
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In addition to connecting the ground (GND), 3.3V power (VDD and VDDIO) and I2C
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pins, both HDC1008 and BMP280 require some extra wiring.
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For HDC1008, connect the address pins (A0 and A1) to GND (this sets the device
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address to the default used by the app). Also connect the RDY pin of the sensor
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to the A1 pin (on ANALOG IN header) of the Arduino board. This is needed as the
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app configures data-ready interrupt on that pin (GPIO pin 3).
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For BMP280, connect the SDO pin to GND and the CSB pin to VDDIO, since the sensor
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needs to be setup to use I2C, and not SPI.
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Internal sensor:
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If you do not want to use any external sensors, you can use the Arduino 101's internal
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BMI160 sensor to do just temperature readings. To do this, you need to modify the
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channel_info array from the ARC application to contain only BMI160's temperature channel,
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and also remove the humidity and pressure characteristic from the x86 application.
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If you choose this approach and you also want to use the Grove LCD, then you also need
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to modify the ARC application to only display temperature on the LCD, as humidity and
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pressure values will not be available.
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Grove LCD:
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Using the Grove LCD is optional and it can be disabled by removing the Grove configuration
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options from the arc/proj.conf file.
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The Grove LCD communcicates with the ARC core though the I2C bus. When connecting the Grove
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LCD to the Arduino 101, either directly (similar to sensor wiring) or through a Grove Base
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Shield, you need to make sure that the I2C SDA and SCL lines have pull-up resistors connected
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between GND and the 3.3V power source.
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Take note that even though SDA and SCL are connected to a 3.3V power source, the Grove LCD
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VDD line needs to be connected to the 5V power line, otherwise characters will not be displayed
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on the LCD (3.3V is enough to power just the backlight).
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