evil weather station™

i figured building a weather station is like learning to play stairway to heaven for a noob guitar player (if they still do that song, might be showing my age here). thanks to some other posts ive gotten the evil weather station™ working (thx to paul, rob, few others), however my problem is timestamping my real world samples. i mentioned this in one of my other posts, actually i hijacked my own thread, so i thought i can get some insight here. i would like to timestamp using epoch, but have no idea where to start with it. is this something i just work out on my own with the math? or is there a snippet available somewhere. i have searched around and cant find anything that i can readily understand easy enough to just implement it. thanks in advance for the advice/help.

just in case your wondering what the evil weather station™ is, i tell it the weather for a location, and it changes the weather to match. :D

How to time-stamp the data depends on where you want to time-stamp it, and how you know the time. Seems you omitted a detail or two.

apologies. i wish to timestamp 3 real world samples, temperature, humidity, and pressure, to an eeprom (25LC1024). http://ww1.microchip.com/downloads/en/DeviceDoc/22064D.pdf

everything is running, including the saves to e2prom, which you helped me work out the other day. i may migrate over to the SD shield, but I'd still like to excercise the prom just to know how to do it, using the timestamp. at this point i have it being saved as a byte for each sample, with plenty of room as this is more or less an excercise in learning. unless i can think of a real world need for the evil weather station for myself, which i cant do unless i buy more UNOs. ah but i ramble. the application of timestamping using epoch method is usefull i think for many projects that i think i may want to do. thx.

The Arduino is IMO not a good place to do your data collection; it would be far better handing the data over to a PC for storage and do your time-stamping there.

If you really want to store the data on the Arduino for some reason and want it timestamped then I would say you need either an RTC, or a network interface and NTP client that can interrogate an NTP server somewhere, or a connection such as your USB interface to a computer which can provide a time source at startup. So you have quite a few options, but my advice would be to not use any of them - store your data in a database on a computer that has the resources to do that job easily and well.

its got a 1302 rtc running on it now, question though, how about field ops? say, what if i want to sample from a glacier? thats actually what i had in mind by storing to eeprom. leave the weather station out in the wild, so authorities cant find it, it is after all an evil weather station™, although your suggestions sound interesting and i think i am going to pursue the database idea, i am much closer to storing in eeprom at this point than anything else. also, this is a learning experience for me. i was looking over some software to capture samples to the pc and graph them etc, but i dont have a budget yet for software. any good freeware programs you know about?

Sounds fine to me, and not that far removed from what I am doing but I'm not sure the EEPROM would be up to the job. I use a DS1307 as an on-board RTC, and it seems to me to be the bleeding obvious way to ensure you get what you want. I imagine your RTC is much the same. If your Arduino can tell you what time it is, it will surely be able to record it. If not, ditch the 1302 and get a 1307 module (battery included) for about $2, and then it can.

I use an SD card rather than EEPROM.

Your software budget should be $0.00. If you already have Excel, that will be useful. Otherwise get Open office.

The following might be entertaining, but this is for live reporting, which is not really what you want.



thx Nick, i download the parallax daq just to play with it. its easy and very cool. but alas, no laptop on the glacier, but i can find uses for these methods. nice weather page also i had seen that once before from someone on this forum when i was researching the evil weather station™.

Hi, If you want timestamp data that looks something like this:

06/10/11 15:36:16,555,489,479

See the code at: http://blog.marxy.org/2011/10/arduino-sd-data-logger-with-time-stamp.html

thanks terry, ive got the sd shield so it looks like this is the way im gonna go for now. appreciate it, very interesting stuff. also gonna check out the link in your sig that stuff looks good to. thanks again, hey, you wouldnt happen to know the where the closest glacier to alabama would be?