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BeagleBone

The BeagleBone Weather cape is an expansion board for the BeagleBone. It enhances the BeagleBone's capabilities by providing environment sensors (temperature, humidity, pressure, and ambient light level).

General Overview

weatherstation

Minix comes with a demo application for the Weather Cape called weatherstation. It's a web application. A tiny web server is automatically started at boot time whenever the weather cape is attached. To use the demo, you just need to plug in the cape and have a working network connection; the system will do the rest.

Requirements

Hardware

Software

Setup

This demo is meant to work 'out of the box'. It requires the BeagleBone be connected to the network and have the BeagleBone Weather cape attached at boot.

  1. Attach the BeagleBone Weather Cape.
  2. Connect a network cable to the BeagleBone.
  3. Power on the BeagleBone.
  4. Configure the network by running these commands. 
    # netconf
# reboot
  5. Enter the BeagleBone's IP address into your web browser.

Usage

This demo is a web application. You just need to point your web browser at the BeagleBone's IP address to view a nice display of the sensor values. You can get your BeagleBone's IP address by running ifconfig on the BeagleBone. If the address is 192.168.12.138, you'd enter http://192.168.12.138/ into your web browser.

Accessing Raw Sensor Data

You can access the raw data via the device files. Simply read from the device file corresponding to each sensor to get the values.The labels and values are delimited by a ':' that is located a fixed number of spaces from the start of the line. This should be easy to parse in most programming languages and in shell scripts. Here's some example output: 

# cat /dev/sht21b3s40 
TEMPERATURE     : 29.126
HUMIDITY        : 45.818
# cat /dev/bmp085b3s77 
TEMPERATURE     : 28.5
PRESSURE        : 100432
# cat /dev/tsl2550b3s39
ILLUMINANCE     : 830
#

Temperature is measured in Celsius, humidity is relative humidity expressed as a percentage, pressure is measured in Pascals, and light is measured in lux.