Thick dad wants to help son with Analogue data Logger project

Archiver

I need your help,
My son has a school project regarding programming for a
Analogue data logger.
It asks that the Stamp capture the data from a analogue I/P data
fixed rate and stores the data to be available to download to a PC
via a serial port. The data capture and downloading to be triggered
from stamp buttons.

The program will capture a fixed number of samples from one channel
from a ADC and be stored in the Stamp EEPROM. A LED will light when
sampling complete to wait for download instruction from a stamp
button via serial port to the PC.

The data capture rate will be 4 samples/second and will be tested
capturing 16 samples of a 1 Hz sine wave.
The program will allow power to be removed from the stamp between
data capture and downloading.

Can you help or pass me onto somebody who can as my son is really
hoping I can help? which at present I'm struggling with this ?

Thanks

Graham

Archiver

--- In basicstamps@yahoogroups.com, "l377472" <graham.evans@w...>
wrote:
> I need your help,
> My son has a school project regarding programming for a
> Analogue data logger.
> It asks that the Stamp capture the data from a analogue I/P data
> fixed rate and stores the data to be available to download to a PC
> via a serial port. The data capture and downloading to be
triggered
> from stamp buttons.
>
> The program will capture a fixed number of samples from one channel
> from a ADC and be stored in the Stamp EEPROM. A LED will light
when
> sampling complete to wait for download instruction from a stamp
> button via serial port to the PC.
>
> The data capture rate will be 4 samples/second and will be tested
> capturing 16 samples of a 1 Hz sine wave.
> The program will allow power to be removed from the stamp between
> data capture and downloading.
>
> Can you help or pass me onto somebody who can as my son is really
> hoping I can help? which at present I'm struggling with this ?
>
> Thanks
>
> Graham

I have code and a board that utilizes a BS-2, an LTC1298 (2-channel,
12-bit ADC) and an LM34 temperature sensor and the code to run it.
It stores up to 500 temperature samples at any interval from 1 per
second to 1 per 4 hours, 25 minutes--you choose. Sampling is
initiated by a button on the board and dumping the sample data is
likewise initiated by a button on the board. A slide switch selects
sampling or dumping. The program talks to StampDAQ which runs as an
Excel macro on your PC. StampDAQ is a free download from Parallax.
Once the data are in Excel, you can graph and analyze the data.

The data in EEPROM is non-volatile, so power can be removed after
sampling and the sample data remain intact until replaced by a new
sample or a new program is downloaded into the Stamp.

I would be happy to share this with you.

Look at Column #4 Nuts and Volts June 1995 by Scott Edwards for an
article describing interfacing to teh LTC1298 ADC chip.

As far as writing and reading to the EEPROM, here is some BS-2 code
that shows a way to save 16-bit sample values in EEPROM:

SampleIntervalSec con 2 ;number of seconds between samples
SampleIntervalMin con 0 ;number of minutes between samples
MaxSamples con 500 ;absolute max samples allowed-
prevents overwriting program in EEPROM

Nsamples var word ;counter of number of samples taken
SampVal var word 'Sample value to store
SampValLo var SampVal.lowbyte
SampValHi var SampVal.highbyte

CurLoc var word ;address to write sample value in
EEPROM
GetSample:
if NSamples => MaxSamples then GetSExit
Nsamples = Nsamples + 1

' get a sample
SampVal = 0 'clear
gosub ReadAdc

' Do math conversion of returned ADC value to real-world value
here
' Sample to save is in the word SampVal
GetS10:
' Compute EEPROM address
CurLoc = NSamples + NSamples

' Store sample in EEPROM
write CurLoc, SampVal.lowbyte 'Store sample low
byte to EEPROM
write CurLoc + 1, SampVal.highbyte 'Store Sample high
byte to EEPROM

' Save number of samples in EEPROM
write 0, NSamples.lowbyte
write 1 ,NSamples.highbyte

' pause sample interval amount of time - pause minutes
if SampIntervalMin = 0 then Gets20

' pause loop
for I = 1 to SampIntervalMin
pause 60000 'pause 1 minute
next
Gets20:
' pause seconds
pause SampIntervalSec * 1000
goto GetSample 'loop
GetSExit:
' Exit
return

You would hae to change this code to pause for 250 milliseconds (or
less, allowing for instruction execution time)) to achieve your
requirement of 4 samples per second.

I built this project for my son to log temperatures on his RC car
engine. It rides on the car collecting samples and we download the
results after the run.

Hope this helps.

Archiver

Graham,

You should get plenty of help from this group.

Do you believe you have all the parts you need? Actually, would
probably be helpful if you post the parts you have.

Do you have any part of the project done?

Are there any specifications on downloading the data to the PC? Can
the data go to a debug window?

It is stuff like that that we need to know.

Happy Holidays,
Frank




--- In basicstamps@yahoogroups.com, "l377472" <graham.evans@w...>
wrote:
> I need your help,
> My son has a school project regarding programming for a
> Analogue data logger.
> It asks that the Stamp capture the data from a analogue I/P data
> fixed rate and stores the data to be available to download to a PC
> via a serial port. The data capture and downloading to be
triggered
> from stamp buttons.
>
> The program will capture a fixed number of samples from one channel
> from a ADC and be stored in the Stamp EEPROM. A LED will light
when
> sampling complete to wait for download instruction from a stamp
> button via serial port to the PC.
>
> The data capture rate will be 4 samples/second and will be tested
> capturing 16 samples of a 1 Hz sine wave.
> The program will allow power to be removed from the stamp between
> data capture and downloading.
>
> Can you help or pass me onto somebody who can as my son is really
> hoping I can help? which at present I'm struggling with this ?
>
> Thanks
>
> Graham

Archiver

Graham

You might find helpful the Stamp-in-Class curriculum that is free for
download on the Parallax web site. The Applied Sensors book re
builds step by step up to a data logger as its final project. I
have some information on A/D converters and sensors on my web site,
<http://www.emesystems.com/BS2index.com>. A good tutorial on a
simple data logger interface to the PC is still to be found on Scott
Edwards' site, <http://www.seetron.com/pdf/dcpb_mnl.pdf>. How old
is your son, and are all the parts provided and prewired for this
programming project, or do you have to do the hardware too! It
sounds like you have your holidays cut out for you.

By the way, Happy holidays, everyone.

-- best regards,
Tracy





>I need your help,
> My son has a school project regarding programming for a
>Analogue data logger.
>It asks that the Stamp capture the data from a analogue I/P data
>fixed rate and stores the data to be available to download to a PC
>via a serial port. The data capture and downloading to be triggered
>from stamp buttons.
>
>The program will capture a fixed number of samples from one channel
>from a ADC and be stored in the Stamp EEPROM. A LED will light when
>sampling complete to wait for download instruction from a stamp
>button via serial port to the PC.
>
>The data capture rate will be 4 samples/second and will be tested
>capturing 16 samples of a 1 Hz sine wave.
>The program will allow power to be removed from the stamp between
>data capture and downloading.
>
>Can you help or pass me onto somebody who can as my son is really
>hoping I can help? which at present I'm struggling with this ?
>
>Thanks
>
>
>Graham