Abstract

WeatherLink is a system designed to measure and record several environment factors. It is designed to allow easy transfer of the recorded data to a PC, for subsequent analysis. With a sampling interval of 5 minutes, the design allows continous logging of over 170 days of data. The included Windows software presents a simple overview over the data, and is capable of exporting data in CSV format, readable by most spreadsheet software.

System features

• Motorola MC68008 processor at 8MHz
• 512kb SRAM
• 16550 UART for RS232, with 9.6 or 38.4 kbaud selectable
• 8-channel 12-bit ADC
• Counter for pulsed input sources (wind meter).
• Temperature, pressure, wind speed and light level sensors
• WeatherLink software for win32.
• Display for realtime weather information and control

• WeatherLink is about 1000 lines of code
• The firmware is about 1200 lines of code
• Hours spent on project: Countless. (Certainly more than 100.)

After considering our demands on the system, we decided to use a Motorola MC68008 processor. This allows for the large memory area required to log large amounts of data. For communication with the PC we elected to use an RS232 interface, mostly due to its simplicity. The WeatherLink software is written in C, using the ordinary windows API.

Screenshot of WeatherLink for Windows. (click to enlarge)

The system is built using wire-wrapping. This metod is used when making prototypes of a hardware system.

Underside of the board, with wires

The course

We highly recomend the Digital Projects course. It's great fun, because you get to use your knowledge 'for real', and you learn very much. It is possible to vary the amount of effort put into the project, to tailor it to your schedule. We like to think we put in a lot. :-)

Authors

David Dufke (e98dd)
Andreas Sörensen (e98aso)