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Hello,

My personal way of hitting this experiment will be to sample all data sets 24/7 for the entire length of experimentation. Fortunately, we can do this if we have a ADC card for the computer. There are a few out there that are around the $100 price tag. The website I posted previously would have these device on hand.

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I'd love to have automatic uninterrupted logging of data. But it's all the extra expenses. I am incurring a lot of them for this right now. Ballasts alone will hit almost $500.00 or more. [img]images/smiles/icon_eek.gif[/img] So far its $200.00 on light meters. [img]images/smiles/icon_sad.gif[/img]

If I could set up something to measure and record mV on my PC I'd be laughing. It's that damned cost again. A rough guesstimate for exchange $Cdn to £ is 2.2. So for a £120 board I am looking at $300.00 once shipping is included. If not more. Then there is duties and taxes. Grrrrrrrrr.

Tho I may talk to the head of my program at BCIT and see if he can get me an interface card somehow. They hav eto exist. It is BCIT after all. All I need is one to measure mV.. all I need.. Then I could run it 24/7 over a couple of weeks and we could see a graphical log of the output decay in PAR for each ballast. Set up a sealed enclosure with one lamp inside and the PAR meter attached inside. Fan for cooling and circulation and you can do 30 days of testing in 1/2 the time. All with some pretty sweet graphs showing the decay.

Hmm.. damn.. more ideas..

Thanks Titus. [img]images/smiles/icon_wink.gif[/img] [img]images/smiles/icon_eek.gif[/img]

Still looking for a Fluke 41 tho. Be nice to measure the wattage with only one meter. [img]images/smiles/icon_wink.gif[/img]

You know. Even if I was only able to get a board made to measure higer voltages and not accurate with the mV, it would be a snap to make up an amlification board the PAR sensor feeds into then the board sends the amplified signal to an interface card for logging. Then it is the software. grrrr..

I do have an extra PC here I could set up to run the collection software only. Hmm..

TITUS! Why'd ya have to bring this up! lol

Just took a closer look at the Data logger Titus.. It is only accurate down to 5mV. I need to 1mV to be accurate. The sensor is accurate to 1mV = µmol m^-2 s^-1. Plus it only measures to 5V. Sigh.

Grrr.. double Grrrrr hmm amplifier.. sigh.. I gotta try n sleep now.. Not gonna happen.

[ 22 February 2002: Message edited by: DJ88 ]</p>

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Found this one in New Jersey. This is a definite possibility. Calling tomorrow for pricing.

PC Voltage recorder.

It has an accuracy of .5mV and can do real time data logging. Comes with software that is easily modified/set up for sepcific uses.

ie. recording 1mV as 1 µmol m^-2 s^-1.

Hmmm..

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Hello,

My thoughts:
-wait a month or two so we can find better data logging solutions
-maybe in a month or two I finish the trouble part of my thesis and can do the acrylic part for you (I already have an idea how), as long as someone is getting the material
-also once I'm done I can actually call up people like in PFO to see if I can talk them into loaning you a ballast.
.... but again it's time. This is a long project that deserves to be done right and proper.

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Well the volt recorder is outta the picture. As i sone other product I found. The VR-101 is $199.00 US and the Gauge Compu Scope is $4,995 US.

I'll do it as I intended. Manual recordings three times a day.

And after talking to Dana Riddle The box will be the size of a VHO lamp and will hold the meter 3" above the lamp with three spots to measure. As well I will be going with 2' lamps. This way once the testing is done I can use the lamps myself.

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<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr> -wait a month or two so we can find better data logging solutions
<hr></blockquote>

With the budget I have set out I won't have much cash to buy anything more than the ballasts and the lamps at this point in time.

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>once I'm done I can actually call up people like in PFO to see if I can talk them into loaning you a ballast.
<hr></blockquote>

Too late. I have already ordered a ballast frn PFO. Within a few weeks I will have a 430, 660, PFO, workhorse and a Tar.

Thanks anyways Titus.. appreciate it.

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Hello,

Is it easy for you to build a cheap simple low speed ADC interface for the serial port? Matlab has serial access functions and the following code sample serve to illustrate how we can use our computers with a simple interface to do continuous data sampling.

Assuming that we want to take a sample every 60 seconds with a timing resolution of 'res':

% Code Snippet
res = 0.5;
previous_time = 0;
current_time = clock;

if [etime[current_time, previous_time) < 60)
pause[res);
current_time = clock;
else
previous_time = current_time;
% Trigger and sample ADC
current_time = clock;
end
% Code Snippet

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Titus,

I wish I had the time. Midterms starting next week. And in all honesty I want to do this with as little construction as possible.

Another worry for bulding the board is that would provide a source for nay sayers to say my results are worthless. If I can give the stats for all the equipment used, there are less possibilities for people to discredit the data.

Thanks for the idea tho.. [img]images/smiles/icon_smile.gif[/img] I'd love to in all honesty.

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Looks like I found what I am looking for Titus. As far as Data Acquisition. take a peek at this. I am waiting to find out if it goes down to .5mV.

DI-194 DAQ

For $33.90US with cable and software I can't go wrong. It's my kind of price. Shouldn't be hard to write the code to just log mV measurements.

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Hello,

Wow! That is inded cheap. Actually the price is only $12.95 USD, isn't it?

The thing has 20Vpp of measurement range with 8 bit accuracy. This is 20V/256 = 78.125mV resolution. Unless they have switches that allow you to make it more precise.