Main Site Documentation

Sdi-12


#1

Hello,

I am an amateur programmer. All of this is exciting and new to me. I am trying to build a system with a FEZ Cobra which monitors sensors using the SDI-12 protocol.

I am wondering if there is a SDI-12 driver for sensors lurking in the darkness. A forum search came up empty handed.

Thanks!
Milo209


#2

It always helps if you add a link to what you are referring to. I bet most users do not know what is SDI-12 :slight_smile:

Se here is a link http://en.wikipedia.org/wiki/SDI-12

So looking at that link, this i just a serial port running at 1200 so I am not seeing why would this not run on any FEZ. Now, I do not know anything about the protocol but the good news is that FEZ run C# serial port just like a PC does. If you can find some code online to handle the protocol on a PC then the code will just run in FEZ with very little or no modifications at all.

Do you have a device with SDI-12? Ever worked with these on a PC?


#3

Yeah seems to be like rs-485 in some ways just slower.


#4

Hello Chimpanzee(Gus)

I will list more references in the future when I make a post. Thanks for linking everyone.

The Decagon 5TE sensors I use utilize TTL or SDI-12. With SDI-12 I can run 10 sensors off of a single serial connector. The only issue is that these sensors need 5V excitation. This makes finding compatible units a little trickier. Most dataloggers on the market only provide 3.3V.

Here is a link to the sensor if you are curious:
http://www.gerber-instruments.com/wp-content/product-pictures/decagon/pdf/5te5tm/5TE5TMIntegratorsGuide.pdf

I currently have a datalogger(which cost $600!) which runs a single sensor(which cost $220) in TTL. It has no screen and the unit has to be removed from the site and plugged into a computer to pull the data off of it. This makes frequent checks on my research in California impossible from my office in New Mexico.

My research expenses are coming out of my pocket. I am hoping to be able to save some cash by building my own datalogger which generates its own reports and sends them to me over the world wide web.

There is extensive documentation on the SDI-12 support group page so I do not believe that it will be too difficult for me to write my own stuff. I just wanted to make sure someone else hasn’t already done it. I do despise having to reinvent the wheel. :slight_smile:

Thanks for the help!

-Milo209


#5

Nice!!! :wall: For what? read serial data and save on SD card?
You can use FEZ Panda $35 to do the same thing! Or use FEZ Cobra to do that + display color + get touch input + send data over Ethernet or wifi + million other things :slight_smile:


#6

Free advertising inside ! :smiley:

But Gus is right :hand:

More seriously, There must be something more to justify that price. Or is it a scam ? :o
Maybe sampling rates, memory, interfaces, I don’t know :think:


#7

One VERY important point when talking about commercial DAQ/data logging equipment is its accuracy and stability. Is does you absolutely no good to collect a bunch of unreliable data. On a commercial DAQ system a lot of work goes into the system to provide a known resolution of the system and stability to things like temperature and voltage. Most commercial DAQ cards will also do synchronized sampling on all channels which may or may not be important to your work.

A FEZ could do a very good job at collecting data but it is up to you to properly condition the analog input to a level that is compatible with the FEZ and then spend some more time to calibrate it and confirm the readings you are getting are sensible.

If you’re monitoring a device over a long distance then reliability and remote upgrading of the system should also be considered. Also the engineering time it takes to get/keep a system working should also be considered.


#8

[quote]More seriously, There must be something more to justify that price. Or is it a scam ?
Maybe sampling rates, memory, interfaces, I don’t know[/quote]

How much are GPS data loggers? They are in hundreds and you can use FEZ Panda to make one over the weekend.

Although this website is targeted for beginners, GHI offers are provided for commercial companies who accept nothing but perfect quality…this is how FEZes have an outstanding quality. As far as what we have implemented (USB, SD, FAT…etc.), we try to bring it to perfection as much as possible. Now, you still have to do the rest on your end and make sure your software is written properly.


#9

I am here looking at a FEZ Cobra because I did my homework and know that they will perform as required for my research. Not to mention that they cost very little in comparison to the current dataloggers I am using.

As long as my sensors receive 5V and have access to a serial connector, they will perform within the margins of error outlined in the sensor documentation…or so the Decagon techs tell me over the phone. :slight_smile:

As far as engineering costs, anything I do will be better than flying out to California to do everything myself on regular intervals. Good help should be easy to find these days with the economy how it is but thus far I have been unlucky. All attempts to delegate data recording to the facility foreman have ended in failure.

When I write a SDI-12 driver and want to share it. How should go about doing so?

Regards,
Milo209


#10

We have many shared code from many users, we all use the wiki now but we are announcing a new website we are bringing up just for code sharing :slight_smile: … stay tuned