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Topic: Seeking help in choosing components for temperature logging and wifi downloading (Read 709 times) previous topic - next topic

We are looking for a very inexpensive way to connect a couple of temp sensors and time stamp and log their output.  Then, after about a month, be able to drive by and download the data to our Android HTC Dream phone for uploading and analysis.

It looks like we need some sort of SD card, obviously.  Perhaps, once we get the thing done we can just set it up with only the components we need as in this instructable...

http://www.instructables.com/id/Perfboard-Hackduino-Arduino-compatible-circuit/

It looks like we will need the Data Logger shield, which will bring our total to almost $30. U.S.

Maybe this card would be sufficient.  It's only $10.00: 

http://www.geekonfire.com/wiki/index.php?title=Logger_Shield#Reading_from_and_writing_to_SD_cards_on_the_Arduino

This whole setup is to track the temperature output of a roof-mounted solar water heater array.

Of course we would still need to factor in the cost of the SD card itself.

Any suggestions would be greatly appreciated.

Have a great evening!  :)


"The earth is one country and mankind its citizens."
Bahá'u'lláh
"La tierra es un sólo país y la humanidad sus ciudadanos."

Nick Gammon

To keep costs minimal you could use something like this:

http://shop.moderndevice.com/products/rbbb-kit  ($US 13).

Get the 3.3V version. Then grab a microSD card with an adapter. Solder wires to the adapter directly from the board (MOSI/MISO etc.).

For time-stamping get a DS1340 board or similar, like this:

http://shop.moderndevice.com/products/jeelabs-rtc-plug ($US 12)

You obviously need some sort of temperature sensor.

Then you could set it up to sleep most of the time, wake every 10 minutes or so using the watchdog timer, take a reading, log it, and go back to sleep.

You would push the microSD card into the adapter to use it, and then pull it out and put into (another) adapter to get the readings on your PC. Or just buy the board you mentioned.

Also the minimal perfboard you mentioned could be another approach.
Please post technical questions on the forum, not by personal message. Thanks!

More info:
http://www.gammon.com.au/electronics

SnJDK

Hi,

if you use Arduino Mega (128/256) or like to connect with other Arduino you may consider to use Data Logger Shield v 1.0 (http://pcb.daince.net/doku.php?id=data_logger) available on ebay.

I use it for many different temperature measuring and logging project. It is available in different configuration depends of needs. For temperature measuring depends what you measure, but in my case I use Maxim IC 1-wire DS18B20.

Best regards
Dubravko Penezic

Thanks a lot, guys.  You have been really helpful.  However i can't get to the setup very frecuently after we install it, but would need to access it wirelessly.  We only need the temperature to the nearest 0.1 degree at the most and would like to log perhaps every 5 minutes.

What additional hardware would we need to get the info from the SD card to some sort of smart phone?  It looks like we need something like the Xbee, but it also needs its own board = $35 total for the two.

We ran into this item / maybe it might be able to replace the Xbee?  http://www.linksprite.com/product/showproduct.php?lang=en&id=116
This thing is evidently only $15.00 (although i can't find the link anymore).

Thanks again for your great suggestions and have a wonderful evening!  :)

"The earth is one country and mankind its citizens."
Bahá'u'lláh
"La tierra es un sólo país y la humanidad sus ciudadanos."

el_supremo

Another possibility is storing the data in a serial EEPROM. Two temperatures will be 4 bytes. The date will be 3 or 4 bytes (and there are ways of storing the data that would use a lot less). So, 8 bytes every 5 minutes is 71kB a month. You can store more than 3 months of data in a 2Mbit (=256kbyte) SPI EEPROM and add a serial real-time clock such as the DS3234.

Pete

Nick Gammon


What additional hardware would we need to get the info from the SD card to some sort of smart phone? 


How close can you get? Those things don't have a great range. Or can you access an Internet point somewhere?
Please post technical questions on the forum, not by personal message. Thanks!

More info:
http://www.gammon.com.au/electronics

Wow, the EPROM suggestion sounds great!  At least you've given us a ballpark figure as far as how much data can be stored plus the suggestion for the real-time clock.

Quote
How close can you get? Those things don't have a great range. Or can you access an Internet point somewhere?


Uh, this is probably the most prickly of the challenges.  We are going to be able to get fairly close - like "out in front of the building" close.  But since the system is going to be up on the roof, we probably won't have much line of sight... although if it could really keep the price down, perhaps we could mount it on the street facing wall -- hmmm.

Thanks for all your thoughts.  As you can probably tell by now we know very little of electronics, but if we can get the hardware figured out, we can find someone locally who could probably put the items together and set up the program/sketch.  (Why do people need to invent another word for "program", i wonder).

Have a wonderful evening!  :)
"The earth is one country and mankind its citizens."
Bahá'u'lláh
"La tierra es un sólo país y la humanidad sus ciudadanos."

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