My First AVR Project - a Lightning Activity Monitor

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I’ve just completed the prototype for my first AVR project. It’s a lightning activity monitor. The idea came from Tim Bitson. I built the sensor unit exactly as Tim describes. For the monitor unit, I used an ATMega8 programmed in C (WINAVR) instead of a Basic Stamp used in Tim’s unit.

The unit lights 1 to 8 LEDs to indicate the number of lightning strikes over the last 60 seconds. The LEDs are updated every 6 seconds. The monitor maintains a “high water mark” and flashes the LED corresponding to the highest strike count since power up.

I also added a 9th LED that is turned on when a strike is detected. This LED is turned off if no strike is detected after 1 second has elapsed.

According to Tim, the unit is capable of detecting lightning strikes greater than 50 miles away. My experience has confirmed this.

Tim’s unit used the Basic Stamp COUNT instruction to count lightning strikes during a 6-second period. I used an ATMega8 external interrupt that is more sensitive to nearby lightning strikes. I’m still in the process of fine tuning the sensitivity. This may take a while since our peak thunderstorm season is past.

Don

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Howdy,

Nice! Cool project, I've always been interested in lighting strikes and whatnot. What are you planning to do with it now? Sell it, upload it to academy, etc?

Also - what are those chips that are inbetween the LEDs and the Mega8, are they buffers? If you respect the maximums on page 240 of the datasheet you can do away with them (400mA max in the whole chip).

Regards,

-Colin

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c_oflynn wrote:
What are you planning to do with it now? Sell it, upload it to academy, etc?

Also - what are those chips that are inbetween the LEDs and the Mega8, are they buffers? If you respect the maximums on page 240 of the datasheet you can do away with them (400mA max in the whole chip).


Colin, I have no plans on selling it. I'm going to build a couple more and package them in a nice case. One will be used at home and another at my lake cottage. If there's any interest, I'll make the schematics/code available.

The chips between the LEDs and the Mega8 are ULN2003A Darlington arrays. I wanted to be able to drive the LEDs at up to 30 mA. I read 200 mA max on VCC and GND in the Mega8 data sheet (page 237). Right now, I'm running the LEDs at around 10 mA so I could have wired them direct. The ULN2003A's were only US $0.64 each and I had room (used ExpressPCB MiniBoard service).

Don

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Hi,

Ah i see - yeah it can't hurt to through some buffers in!

Anyway I'd be interested in schematics and code eventually if you throw it up there.

Regards,

-Colin

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Very cool project!

And thanks for the link to Bitson's page.

I now have a new project! I live in a moderately high lightning area too. Plus I went and bought me one of those BetaBrite LED signs down at the Sam's Club - which happens to have an RS-232 interface.

Combine that with some software to post headlines from web RSS feeds, a lightning stroke count when there is one, hate to admit it but a count rate feed from a Geiger counter, and this is becoming a real nerd project!

Please note - this post may not present all information available on a subject.

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refields wrote:
and this is becoming a real nerd project!

Your comment reminds me of what my wife said when I showed her the lightning activity monitor: "I know it's cool and everything, but does it have any practical use?".

Cool use of the BetaBrite LED sign. I've seen it at Sam's club too and thought it would be neat to play with.

Don

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I'm in Orlando... Cen Fla claims its the lightning capital of the US... central tTexas is supposed to be real active too.... after that its the Amazon basin or something. Send one down. It'll get tested! My boss has a Stormscope in his Twin Comanche. Shows the range to the strike on a plasma display... need two loop antennas in quadrature to get angle (rearrange the leds in a circle, or concentric circles for range). To get range, I guess you assume that all strikes are about the same strength close up, then its an inverse square law type of thing, right? Like a far away strike is a little static on the AM radio, a close strike is a LOT of static... evelope detector.....

Imagecraft compiler user

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bobgardner wrote:

Shows the range to the strike on a plasma display... To get range ...
a far away strike ... a close strike is ...

For a simple close-strike detector, hang another one of the AVR boards from the mast that is shown in the photo. Then, use binoculars: If the hanging circuit board is black, you know that it was a close strike. :wink:

Lee

[and if the board is wet, you know it rained during the thunderstorm, etc.]

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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If the board is hot, its sunny out.... sort of a 'hi tech weather rock'

Imagecraft compiler user

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And if there ain't no board - a cyclone has just hit you