Data logging, logger VS micro SD

Projects Discussion and Showcase Science and Measurement
1

Hello,
I am part of a group that is running experiments with pressure sensing using the Arduino.
In order to save our data we have been printing to our serial monitor and copying to Excel at the end of the experiments. This method is clearly not very good and we would like to upgrade.
I've tried using the PLX-DAQ program that I've found on the forums, but it isn't very robust.
I'm thinking that I should use either a micro SD module or a data logger such as this one:

Price isn't a huge issue, so if you guys could tell me about the pros and cons of these methods I'd be very happy.

2

Teraterm can do logging.

3

+1 for logging from a terminal program. I write ".csv" files (comma separated values), which can be directly read into Excel.

Teraterm will also add a system date/timestamp to each record, which with a text editor can easily be manipulated into a form that Excel can read.

4

Not sure I would entirely trust a microSD card for datalogging.

Dont understand why you think printing to serial "is clearly not very good" you can create a CSV file directly, logging to Teraterm or Coolterm is dead easy.

I would do the best of both, put an openlog (cheap micorSD card logger) on the a serial port, which could be the same as the program upload port.

You could even arrange the openlog on a spare I\O pin and send the logging data to both the serial monitor and the openlog.

5

jgreenb:
I've tried using the PLX-DAQ program that I've found on the forums, but it isn't very robust.

I have never heard of that before, and I rather suspect it is code for "I don't know what I'm doing". The using PLX thread is one of the most comprehensive on this forum and, if you want to use the data in Excel and you have the connection to do it, putting it there in the first place is the obvious way to do it.
http://forum.arduino.cc/index.php?topic=437398.0

6

I've run into trouble with PLX-DAQ using high Baud rates (e.g. 115200). If you try to send a lot of data, it gets bogged down, misses transmissions and sometimes even crashes.

Solution: lower the Baud rate.

7

It depends if you are always running these experiments on a PC connected Arduino or if they are run autonomously.
If these are autonomous, then there are many options for collecting and sending the data. If the data is batched locally (sd card, eeprom etc.) you may need an RTC tor adding time stamps. If it is sent in real time over a WLAN to a, for example, web server and stored in an SQL database, then time stamps are added by the storage program.

8

Python talks serial and can interface to a whole variety of storage options from files to databases to web
servers and can do live graphing if you want...