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DEMO :: Monitoring and Data Logging : Ambient light level and temperature

MONITOR PANEL

Velleman K8055

A photoresistor (resistance varies with the intensity of light) is attached to one of the K8055 project board's analog inputs, which is connected (USB) to a computer. The computer runs a Java application on Linux Ubuntu, which reads the value from the board and transmits it to our server via an Internet connection. The graph to the left displays the last few hundred readings. It is located in our workshop in Centurion, and may sometimes be visible in the webcam image in the CONTROL section.

The above graph shows the ambient light level (green) and the temperature (yellow) in our workshop as a value between 0-255, and is updated every 15 seconds. The background is gray-shaded according to the intensity of light, whereas the coloured strip at the top depicts the relative (to the span of the graph) temperature. Hover your mouse pointer over the top temperature strip to display the temperature in degrees Celsius, and hover your mouse pointer anywhere below the green (light level) line to see the value (0-255) of the current light intensity.

The image below is another representation of the light level, but in stead of being dynamic, interactive browser-generated display element as the graph above, it is rendered by the server as an image (allowing the user to download and save the image, unlike the graph above). Note that this particular image is drawn from right to left, i.e., older data is to the right, latest data is to the left.