Gurus,
I'm working on a homemade weather station and I would like to detect lightning. Does anyone have a suggestion for a cheap and easy solution? This is a learning project for me so I don't want to buy a prefabricated system. It's a processor based system that feeds the data to a PC running Microsofts version of Windows with a program written in C or C++ . Any thoughts?
if it's dark, it should be quite easy to detect lightning. Try multiple fast light sensors in different directions and require more than one to trig at the same time. With a single sensor, a reflection of the sun may generate false matches.
However, it may be very hard to detect the lightning in daylight conditions, since the contrast will so much lower, making it hard to calibrate the trig level for the sensors.
The individual strokes are very short, so it can probably be hard to use an ADC to constantly scan the sensors. Easiest would be to use a comparator to generate a digital pulse, but it would probably take a bit of work to figure out a good trigg level. A sample-and-hold circuit could be used to catch the peak intensity detected.
This forum is for discussing Keil products - ie, Keil software tools, and Keil boards: http://www.keil.com/forum/
This doesn't really have anything to do with Keil or even ARM processors - what you really want is a forum about meteorological instruments...
I think you would have to employ some more sophisticated processing to handle false alarms. you may need to do some processing to filter out patterns based on time and shape. you may even require quite some sensors to allow for that (e.g. increase you resolution). there are cheap light sensors out there that connect to your processor's I2C bus, so no ADC is required actually.
the I2C sensor that I mentioned mostly allow you to adjust their gain, thereby allowing you to setup the system's sensitivity as required by weather conditions etc.