New Dataloggers

[SparWeb]

I've been missing the forum a lot lately.  Business trips, heavy workload, more house problems, life seems to intrude on my leisure...
I haven't even begun to read through the long list of un-read postings and replies that I've missed in the past few weeks.

Today I have something worthwhile to post about:



I bought a bunch of dataloggers.  Yeah: I got lots of them.  A government auction and I had to take all or nothing.  This is one of 24 recovered from a cancelled government environmental survey; river and stream flows in the Mackenzie river valley south of Inuvik.  (Find that on google maps for fun).  They're all a bit old, a couple had water in them (probably scrap then) but the majority look clean and undamaged in their weatherproof cases.

I've fussed around with dataloggers for years, building my own because I want something just right and not to complicated to understand.  Well I've reversed that, and picked up a stack of some of the most complex dataloggers out there.  I have a variety of types, but most are the Sutron 8210 which has been in use by environmental science for 20 years or so, and still on the market.  Those automated weather stations you drive by on highways probably have a datalogger like this one at the base.

Hooked one up to the computer tonight, and it's responding properly.  The guys using it before have wiped the memory, and they were conscientious enough to remove the batteries (which would have leaked or failed anyway since they've been stored for several years).  They included the setup CD, a few power cables, spare fuses.  Really nice deal.  I don't have any of the right sensors so either I'll get a few new ones or look for old ones.  The system is flexible enough I could just rig up my own (like I've done before) and work out a reasonable calibration.

Looking inside, several of the units are just dataloggers, but most of them have either a modem (for telephone telemetry) or a GOES satellite transmitter board.  I will need an antenna or a dummy load before turning one of those on (may still be set to broadcast periodically).  I doubt I would use a GOES - you have to sign up for access and that just assigns you a daily transmit "slot" according to what I've read (this is the first time I've read about GOES telemetry).

Now that I've got so many, the project ideas just keep coming up:  detailed wind survey around my property, energy consumption of my house and appliances, more WT performance tests...   

[DamonHD]

Hmmmmmmm, data!

Yes, there's always slightly more things to log than you have devices to log with!

Here's one of my simple logging projects, though rather less grand than you could do with that stuff:

http://www.earth.org.uk/note-on-iButton-temperature-monitoring-of-aerogel-drylined-bedroom.html

Anyhow, well done, good catch!

Rgds

Damon

PS. Envy envy envy

PPS. Relative humidity seems hard to do right and on a budget: I'd be especially interested if you do any of that...

[SparWeb]

Finally getting somewhere with these dataloggers.  First thing to do was to clean them up!  Several were filthy when they arrived, so I methodically cleaned them all in the garage.  Some were pristine, others infiltrated by water, some were even worse (you don't want to know!)  Then I brought the stack into the house for power-up and hook-up to the computer for a looksee.



Some didn't respond.  Some responded with errors.  A reset on the motherboard fixed most that wouldn't start at first.  There are others that just refuse to work.  Currently I have 16 of the 24 in working condition.  Some are still drying out before I test them.  They're all pretty much identical, meaning old versions of the datalogger that's been superseded twice by the OEM.  But, it's still supported on the website and software downloads still work.

This weekend I put the first one through an actual logging session.  Just light measurements from a photocell, but the fact it's collecting data and I can access it is proof that I have a working unit.  Hopefully many more that work like this one.  Later to test are things like the Counter inputs, and if I'm ambitious, some of the SDI digital inputs.

[SparWeb]

Damon,
About RH% measurements, have you taken apart the wall-mounted controls, such as those seen in bathrooms?
There's a plastic strip that seems to expand and contract with its absorption of moisture, pulling or relaxing a spring.  The torsion spring rotates when it's pulled, tipping a mercury switch, and this part is much like the wall thermostat for central heating systems.
Anything useful in that for you?

[DamonHD]

I didn't know about that style of RH sensor: that's interesting thanks.  I don't think I've seen a control like that.

Rgds

Damon

[SparWeb]

Had to wait for my son to finish his shower...   Photos of the RH% control that flips on my bathroom fan:











Progressively looking from outside to inside.  Photo 4 is the underside, and across one of those pins is looped the tape.
Photo 5 is the little window near the top, and you can see the tape as it loops up around the pin and down.  The pin is through a lever which pulls the switch.

[DamonHD]

Yup, new to me!

Now presumably those are simply on/off switches with hysteresis rather than capable as-is of giving a graduated readout to be logged?  So I'd need a clever torsion logging device and some calibration to get %RH?

Rgds

Damon

[SparWeb]

Just on-off in this "package", but the control knob shows that there is an adjustable resistance that the extensible tape overcomes.  Rotate the knob and the switch clicks over at a different point.  What that means to me, is that once this device is disassembled, the tape and the spring can be put together in a different way and be rightly-sized for each other.
Ie: in series with each other instead of in parallel, so that the joint between them can control a potentiometer slide.
That tape is looped over once so it seems to me that you could either have it straight for 2x the displacement or looped more for #x the force.

Sorry, any further disassembly of the switch could be "destructive".

[DamonHD]

Yes, please don't break it on my account.  B^>

Good to know of that mechanism, I'll keep it on the back-burner for when I have a little more time!

Rgds

Damon

[SparWeb]

First batch of data, actually logging something.  In this case, I put a photocell in a voltage divider between 5v and 0v, and pointed it at the lights in my kitchen.  To set up I turned everything else off so the "dark" read as 0.002v.  The kitchen has CFL bulbs in the overhead and they take a noticeable time to "warm up".  So this run measured the rise in light intensity, in 2-second intervals.



The slow rise time took several minutes, as you can see, to get to 90% intensity.  When I shut it off, and then on again, it rose to 90% almost immediately, but if I left the light off for more than a minute, it had to slowly warm up all over.  A very unexpected thing is the "blip" just after I turn it on, cold, and it gets DIMMER for 15 seconds, before creeping back up.

All this just proves that I have a simple circuit that shows the old datalogger still works, records, and spits the data out in a form I can use.

Just 23 units more to go....