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Davis Instruments Weather Stations / Re: ProData analysis of Davis VP2
« Last post by johnd on Today at 04:41:41 AM »
Just to be 100% clear, this isn't our (Prodata) review, it is Stephen Burt's. I know Stephen and we did supply the station for his review, but it was done strictly on the understanding that the review would be fully objective, warts and all, and any significant weaknesses would not be glossed over (though, as it happens, the VP2 did pretty well). Stephen also gave permission for his review to be used on our main website.
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Tech Corner / Re: Adding LED (or?) to shield fan help
« Last post by DanS on Today at 03:39:12 AM »
Lots of fun. I enjoy projects like that. Just be sure to have all your parts gathered, assembled and tested first before taking your station down to minimize down time.
You can Google "555 as a missing pulse detector" and click on "Images" to get lots of ideas and answers.
I think you mentioned that you're using a computer power supply and if so you may be able to use a standard power cable assembly to cut and splice your new circuit and plug right in.
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Tech Corner / Re: Adding LED (or?) to shield fan help
« Last post by Bashy on Today at 03:07:36 AM »
Thanks, this could take a while, i cant even remember what size fan fits the opening, i think it maybe an 80mm.
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Tech Corner / Re: Adding LED (or?) to shield fan help
« Last post by DanS on Today at 02:56:55 AM »
Down at the power supply end for sure. Just extend the tach wire down from the fan to your 555/led circuit. You would need to use the 12v and ground connections from the same power supply as well.
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Tech Corner / Re: Adding LED (or?) to shield fan help
« Last post by Bashy on Today at 02:43:02 AM »
Ok, thanks, next one is this, would the length of the cable degrade this pulse signal, cable is perhaps 5m
just need to know if it would need to be at the fan end or at the PSU end please?
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Tech Corner / Re: Adding LED (or?) to shield fan help
« Last post by DanS on Today at 02:34:34 AM »
correct.
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Tech Corner / Re: Adding LED (or?) to shield fan help
« Last post by Bashy on Today at 02:29:46 AM »
Ah, ok, so then the 555 will then light the LED
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Tech Corner / Re: Adding LED (or?) to shield fan help
« Last post by DanS on Today at 02:26:06 AM »
The 555 timer chip can be setup as a "missing pulse detector" to monitor the tach output of the fan. The fan stops and no more pulses out of it.
 The PWM (Pulse Width Modulation) lead of the fan is an input to it. A throttle so to speak.
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Tech Corner / Re: Adding LED (or?) to shield fan help
« Last post by Bashy on Today at 01:44:18 AM »
With what you said about the fan dupreezd, why would a 555 (had to look that up) be needed if the LED does in fact
turn off (or on) when it comes to a stop? please? I have also looked at the 3 and 4 pin fans online and both the
sense (tacho) and PWM have pulses to them, would the PWM work better then the Tach in this instance?
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Davis Instruments Weather Stations / Re: New Davis VP2 spec sheet
« Last post by ValentineWeather on Yesterday at 10:37:40 PM »
Love the flat line of the Vantage pro2 ISS and SHT31's. The other chart says external temperature probe accuracy, not to be confused with the SHT31, this is the stainless probe with RJ-connector. 

Here is the PDF for the stainless sensor : https://www.davisnet.com/product_documents/weather/spec_sheets/6475_6477_SS.pdf
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