Author Topic: LR4/414D laser snow depth sensing  (Read 1999 times)

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Offline mikeym2m

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LR4/414D laser snow depth sensing
« on: January 21, 2016, 01:31:51 PM »
Richard from Porcupine Labs has updated the LRTimelog.exe program to produce only a single reading during it's sampling. This eliminates the problem of the Dallas 1-wire reader program seeing multiple readings during the laser "ON" time.

http://www.porcupinelabs.com/lr4-sample-software

Again Richard has be very helpful updating the software to work better with WD.  Great customer support!  =D>

Cheers

 :D

MikeyM

Offline DaleReid

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Re: LR4/414D laser snow depth sensing
« Reply #1 on: June 23, 2017, 08:39:05 PM »
 Having been distracted (and snow melted) from the project, I now have the board and the Fluke so I'm starting to brainstorm.

- A ) is there a best way to get the info back from the ranger/board combo to the house where the monitoring computer will be?  I anticipate a run of maybe 150' or so, and probably through a buried cable (UV/Ground safe).  I think that a USB extender like this one

http://www.ebay.com/itm/WEme-USB-2-0-Extender-to-RJ45-Over-Cat5-5E-6-Connection-up-to-100-Meter-328-F/142312457099?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649

to get the data inside the house.  Something better come along in the last 6 months?

- B) The latest version of the Fluke doesn't like to be cold, at least according to several folks' reports here, and I'm thinking if I'm burying cable to get data in, I'd better bury low voltage AC or a GFI protected   120 v. outlet (then I could run all sorts of stuff out on the post/Stevenson/clamshell weather protector.  So what is the best way to heat the little gizmo without wasting current and making it too hot, too?

I'm thinking that a piece of PVC pipe 3" with a round top cap, then a reducer from 3" down to 1" or 1.5", as the open end.  Make some clever piece of internal support that would allow positioning the ranger so it fired out the hole, and yet didn't wobble around, and then place some sort of heating device inside.  I know a simple resistor would do, but I've heard of folks using an aquarium or herpitarium heater for melting snow in a Davis Rain Gauge, and maybe something like that would do.  It would be nice if it would turn itself off above say 35 to 40 degrees to save energy rather than run all the time.

I'm thinking of mounting the unit with a couple of bands or something around the PVC, but would I be well served to wrap the whole shebang every year with some aluminum foil backed FiberGlas insulation to help cut down on the heating that would be happening during really cold wx, even if there wan't much snow?  I dont want to be turning this thing on and off manually if I can possibly help it.

Anything else that those with successful systems have thought of or implemented since the discussions went forward?

I don't mind experimenting and learning, but for someone else to have discovered neat or revised ways of doing things I could better spend my time working on other projects with my limited time.  Winter's coming!
Thanks for any advice and encouragement.
Dale


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Offline mikeym2m

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Re: LR4/414D laser snow depth sensing
« Reply #2 on: June 26, 2017, 12:55:02 PM »
Dale

I used a simple heater consisting of a 20 Watt 10 ohm ceramic power resistor and a disc thermostat that comes on about 35 deg F and off about 45 deg F. Photo does show 20 ohm resister, but I changed that to a 10 ohm resistor for more heat.
Similar to this:
https://www.amazon.com/Thermostat-Switch-Circuit-Large-Flange/dp/B0026S6WGK

Nice part is it's powered by 12 volts so I don't have to run 120 VAC, which I prefer not to do, out to the sensor.

For the USB extender I'm using a Tripplite version:   
https://www.amazon.com/Tripp-Lite-Hi-Speed-Extension-U026-20M/dp/B006KSLF6E/ref=sr_1_2?s=electronics&ie=UTF8&qid=1498495167&sr=1-2&keywords=tripp+lite+usb+extension+cable+20+m

Don't go cheap on the active USB cable. I've also used the USB - CAT5 adapter with some success.

Great time to be working on the project for next Winter.

 :-)

MikeyM
« Last Edit: June 26, 2017, 12:57:12 PM by mikeym2m »

Offline DaleReid

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Re: LR4/414D laser snow depth sensing
« Reply #3 on: June 26, 2017, 05:27:13 PM »
Mike, well the hostas are a couple years old and only need some mulching, 8,000# of decorative boulders are about in position, the pea gravel for the walkways has replaced the wood chips of last year, and I figure it is time to do some of my work.

I sit on top of a hill surrounded by not only shale under a few inches of soil, but some very tenacious oaks that necessitate a longer distance from the house to found a semblance of small patch that may reflect true snowfall.  Therefore I am probably stuck with the CAT5 solution with the possible run of up to 300'.  And to power DC that far might be tough, too, but I wonder about low voltage AC to the post, and then a rectifier to make it DC for the heater, or maybe the setup will run on low voltage AC, too.  The shale makes any tunneling and laying of conduit tough.

Had you come up with a clever way of being able to reliably position the laser ranger inside the PVC and not have it wobble all around?  Velcro to a crossbar?  some copper pipe strap to  make it malleable and shape it to the correct position and use some tie wraps to secure it for all winter?  I can imagine some high priced government project would have three way screw adjustable mechanism to allow precise aiming, like maybe one of those pyranometer plates that allow leveling, but I'm hoping for something a bit less costly.

One idea I had was to use a round plastic plate that would nest into the PVC pipe onto the bottom reducing coupler, with a hole drilled center to allow the laser outlet from the ranger fit sort of snugly into it, and then use some plumber's clay to help hold it a little bit firmer.

Thanks again.
Dale
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Offline mikeym2m

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Re: LR4/414D laser snow depth sensing
« Reply #4 on: June 26, 2017, 07:50:03 PM »
Dale

I actually mounted a small piece of wood inside the PVC with holes drilled in and attached the 414D with tie wraps. I'll see if I can find a photo. If not I'll be bringing in the sensor for the Summer and I'll take some pictures.

I would think the low voltage AC rectified to DC should work. My sensor was drawing about 1.2 amps with the 10 ohm resistor.

The location I have for the sensor is not ideal as I have a fairly small lot with lot of tall trees, but it's the best I can do.

I put a piece of thick rubber on the bottom and cut a hole the outline of the sensor to try to keep moisture out and it has worked well for several years. I previously had it mounted in a rectangular plastic electrical box, but I wanted to try to reduce the snow that was blocked directly under the sensor.

Good luck with the project.

 :-)

MikeyM

Offline DaleReid

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Re: LR4/414D laser snow depth sensing
« Reply #5 on: June 26, 2017, 09:53:11 PM »
Mike, thanks for the hints, and the idea about a piece of thin rubber to help seal it too.

When I get a 'grand plan' and start, I'll take some pix along the way.  I appreciate your sharing.  I would guess the bottom seal would also make the heater's job easier, without having all the heat go out the bottom with every swirling wind gust.
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