This shows the last readings from a photocell placed in my garden, to monitor sunlight conditions. This ran continuously for about 1 month. We are growing a broad bean plant. While not the same as French beans being grown in Kenya and Kew Gardens, this is for experimenting with interfaces for live sensor data. Shown here is only a first example. A text file with the raw data can be seen here. This live data will be available for a few weeks.

The raw data so far is interesting. Light values range from 0 to 1024, and in the captured data it can be seen that this reaches 0 at about 1 AM. An early an fast sunrise can be seen at about 4:30 AM. The first full day has been cloudy, and this archived image shows changing lighting conditions throughout the day. Day, night, cloudy and sunny conditions could be inferred by looking at threshold values.

Data is being captured from a photocell placed in a window in the sunniest part of our garden. The garden is beneath the ground level, and trees as well as the building block most of the sunlight, so I am interested in measuring the changes in sunlight during the early part of summer.

Data is collected by an Arduino Diecimila hooked via USB to an Apple Powerbook G4 which is running a program created to upload text and image. The visualisation is only a first experiment. The program is created in Processing which is free and open source and supports Windows and Linux, which means that such a program could run on an embedded computer such as Gumstix. An alternative would be to remove the PC and upload directly with embedded cellular modem. A solar-powered Bluetooth Arduino has also also been tested.