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Author Topic: Ultrasonic snow depth gauge  (Read 71068 times)

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Offline eongibier

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Re: Ultrasonic snow depth gauge
« Reply #75 on: August 10, 2008, 05:56:25 PM »
Good evening,

Here the model of my detector of snow which I use.

Serge
France

Offline MichaelPT

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Re: Ultrasonic snow depth gauge
« Reply #76 on: August 17, 2008, 03:47:58 AM »
Hi everybody

I am starting to build a snow sensor we don't get much in the UK
but you never know

My question

On my 1 way system

I am using a solar sensor, soil moisture sensor, and a wet leaf sensor

I've noticed in whether display 1 wire settings there is a box for the id rom for a snow sensor
what hobby board does this relate to

The module I have chosen message from 0 - 6 feet  1 inch equals 10mv



Thanks

mick
« Last Edit: August 17, 2008, 04:04:13 AM by MichaelPT »

Offline Weather Display

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Re: Ultrasonic snow depth gauge
« Reply #77 on: August 17, 2008, 05:11:19 AM »
its a mv ADC (battery voltage sensor)
e.g like the leaf or soil moisture sensor

Offline MichaelPT

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Re: Ultrasonic snow depth gauge
« Reply #78 on: August 17, 2008, 08:59:43 AM »
Hi

I have a spare hobby board moisture board, which would be perfect for this

Will this work alongside the other two moisture boards.  I am using
thanks
 :)

Offline Pieter

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Re: Ultrasonic snow depth gauge
« Reply #79 on: August 24, 2008, 11:31:26 PM »
Greetings from a newbie to this site:

Last year I constructed an ultrasonic snow gauge.  The object was to make one that was completely wire free because several identical units might be placed in locations with no power within a 5 mile radius of the HQ building.  I used a pair of XBee-PRO PKG RS-232 RF Modem radios (short range only for the moment) and powered it with solar panels and batteries.  Due to the limitations of battery power, I can't have the sensor or radio modem on full time.

Instead, I use a Parallax BASIC Stamp PLC to contol the system.
(http://www.parallax.com/Store/Microcontrollers/BASICStampModules/tabid/134/txtSearch/plc/List/1/ProductID/290/Default.aspx?SortField=ProductName%2cProductName)
The PLC turns on the sensor, takes multiple readings, averages them, turns on the radio modem, send the readings, and then shuts off the radio and sensor and enters "sleep mode" for about three hours.  The way to tailor the load to the battery and solar array is to vary the time between readings - the longer the "sleep", the less power per day is consumed.

Before 2007-2008 winter set in here the system was up and running.  It could accurately and repeatedly measure the distance to the plywood measurement "ground" surface.  It could accurately measure the height of my "test snow" - piles of cardboard boxes.  However, when the snow arrived, the system could not measure snow depth.  It didn't matter if the snow was soft and fluffy or had a crusty surface, the sensor would respond as if all the ping had been absorbed by the snow (showed maximum range) .  It used an EMS sensor (http://emssensors.com/ultrapics/s1225sp.htm), and since this sensor does not have an adjustable gain control, there was no way to experiment with boosting the gain.

This summer (2008) I decided to try some modifications.  I used a SensComp Mini-AE sensor (http://www.senscomp.com/specs/Mini-A%20PB%20spec.pdf) which has adjustable gain as well as range zeroing features (which I won't use).  The sensor is mounted in a Davis weatherstation pagoda.  This was not an original thought - I borrowed the idea from another snow sensor (http://voksenlia.net/met/snow.php), so I hope that it will adequately function for me.  At least I have some confidence that this sensor will work, and its relatively cheap and water resistant when in a housing.  It is also internally temperature compensated, so I don't have to program a speed-of-sound routine.  Sheltering it in a pagoda should keep it at ambient temperature without undo sun heating.

Today I began system calibration.  I know the the PLC is translating the analog voltage from the sensor correctly since it provides an ASCII output of the analog voltage appearing on the sensor lead - good to 1 millivolt.  The PLC will also output the snow depth in inches by subtracting the current reading from the sensor reading of a base measurement table (no snow), thus providing the height of the snow surface from the ground.  IN addition, it will also send the current battery voltage so that I can keep an eye on "system health" by monitoring the state of the power supply.  If the battery voltage dips too low after several cloudy days, the charge controller will turn off power to the PLC until the batteries are recharged.  The PLC will then restart and reboot.  The charge controller will also limit the charge rate to a temperature compensated sfae level for the batteries ( two 12 volt 7 amp/hr gel acid batteries).

This system is a rough prototype for a device which could be part of a network of a hub PC storing data sent by several automated gauges in the field.  The current XBee short range radios could be replaced by long range units (up to several miles range) which have the ability to be hardwired or programmed to send a unique ID with the data record. It would be easy to set up a net using identical systems and only changing the unique ID code on each unit.

At the receiving end I have an old PC (which also hosts our Davis WeatherLink software) on a LAN running a serial port monitoring program which simply dates all the incoming data transmissions from the snow gauge and maintains them in a log file.  I am also running FTP host software on that PC so that any interested researcher can use a browser to download the data files containing snow depth data for future analysis. 

Why do all this?  I work with a group that is involved in endangered butterfly habitat restoration, and one of the unknowns in our world is the ability of butterfly eggs to "winter over."  It appears that butterfly eggs, laid on the stems of host plants may be protected by the accumulation of insulating snow.  While there are volunteers out there reading manual snow rulers all winter in several locations, the use of automated snow gauges the use of might be helpful in assuring some level of measurement consistency.

If all of this works, the next step would be to begin to pick away at the costly items and try to drive the unit cost down to a reasonable level.

I hope some of the experiences here will be of help in other's efforts to design ultrasonic snow gauges.

Warpdrive
 

Offline niko

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Re: Ultrasonic snow depth gauge
« Reply #80 on: August 24, 2008, 11:39:55 PM »
Hi, great information.

Where are you?

Offline mikeym

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Re: Ultrasonic snow depth gauge
« Reply #81 on: August 25, 2008, 01:32:52 AM »
GREAT !! Nice to see some more people working on snow depth sensors.Mine should be moved back outside for more testing within the next week or 2. So far it has been working flawlessly attached to 100 ' of shielded CAT5 cable in the computer room. The problem that I had last Winter was HUGE spikes in the data, but due to several modifications I made and a different interface board, a HobbyBoard humidity board minus the humidity sensor, everything seems to be working fine right now. Time will tell.

Cheers

 :D

MikeyM
http://mikeymsweather.com/

Another VERY Happy WD user
Jetway Dual Core Atom D525 1.8 GHZ  2.0 GB RAM
Davis Vantage Pro wireless w/ Davis solar sensor
Laser Snow Depth Sensor LR4/Fluke 414D working in WD thanks to Brian

Offline eongibier

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Re: Ultrasonic snow depth gauge
« Reply #82 on: August 25, 2008, 03:37:04 PM »
Really super, as says MikeyM, for my case it works correctly.
Serge

Offline mikeym

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Re: Ultrasonic snow depth gauge
« Reply #83 on: September 21, 2008, 04:25:50 PM »
Here's the latest graph being produced with GraphWeather. This is a graph of today's current level of snowfall. Currently reading 26.6 - 26.7 inches under an indoor test setup. I'm still having problems getting the weekly, monthly and yearly graphs to display correctly, but with some help from the GraphWeather forum I hope to get those working also. At least we're making progress and have gotten rid of the spikes that plagued eongibier and I last year.

http://home.ptd.net/~mikeym/graphsnow1.jpg

Cheers

 :D

MikeyM
http://mikeymsweather.com/

Another VERY Happy WD user
Jetway Dual Core Atom D525 1.8 GHZ  2.0 GB RAM
Davis Vantage Pro wireless w/ Davis solar sensor
Laser Snow Depth Sensor LR4/Fluke 414D working in WD thanks to Brian

Offline Stronghurst

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Re: Ultrasonic snow depth gauge
« Reply #84 on: September 21, 2008, 05:36:29 PM »
Very nice.  I hope it does well.


Mark
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Offline ohararp

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Re: Ultrasonic snow depth gauge
« Reply #85 on: November 21, 2008, 01:37:24 PM »
MikeyM,

Great project.  I have worked to develop a system using the Senscomp Sensor and their 6500 Ranging module.  You can see some details from our www.ohararp.com/blog.html

Quote
Recently a climatologist in Norway has asked us to add a Senscomp Ultrasonic Sensor and a simple temperature sensor to our SD GPS Data Logger to track snow depth measurement and glacial velocity movement on glaciers in the North Atlantic Region of the world. Using our skills we developed a quick prototype for initial testing at a fraction of the cost of traditional weather stations ($6K vs $400). We included a 10AH lithium ion battery and solar charging to boot! Let us know if you have a custom app that you would like us to look into! In the meantime enjoy the photos!

This was our intial version, but we are going to be adding some long range radio modules that are similar to the XBEE devices to your units.  We then intend to serve this information to the ethernet with a simple serial to ethernet converter or possibly an FTP connection.


Offline Pieter

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Re: Ultrasonic snow depth gauge
« Reply #86 on: February 03, 2009, 01:54:17 AM »
Some time ago (8/2008) I posted a long message about my attempts to use an ultrasonic sensor and a Basic Stamp programmable logic controller to build a snow depth sensor.

Much of it works fine.  It is solar powered, using 2 12 volt panels to charge 2 alarm system batteries providing both 12 volt and 24 volt DC power.  The sensor is a SensComp mini ae, and the output is an analog voltage (0-10VDC) which the analog-to-digital converter in the Stamp PLC converts.  The data is then sent by radio modem to a nearby (indoor) PC where I can access it via FTP over the internet.

 All the above works fine EXCEPT:

The SensComp sensor ( Mini-AE # 616100) works perfectly when presented with pieces of plywood at differing heights.  All are reported correctly.  When the snow started, it immediately reported 9.99 volts.  In other words, it reports maximum range voltage, which I interpret to mean the echo from the snow surface is not being "heard" so the assumtion is it is beyond maximum range.  There is a sensitivity adjustment on the sensor itself which is currently set to maximum.  The sensor is about 8 feet from ground level, and the snow depth is currently about 2 feet.

I have visited one website for a somewhat similar system employing a senscomp Mini-AE and remarks there suggest that the sensitivity may be set too high. 

see:   http://voksenlia.net/met/snow.php

Does anyone have any experience with this sensor?  Its very difficult to get to the sensitivity set screw on the sensor as mounted, and I was hoping to avoid doing this too many times if possible.

Thanks, Warpdrive

Offline mikeym

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Re: Ultrasonic snow depth gauge
« Reply #87 on: February 03, 2009, 02:33:20 PM »
Hi Warpdrive

I'm using the Mini-AE # 616105 sensor which is the .5 - 20 ft sensor and I have the sensitivity set to about 2/3 or 66 % like Steinar suggested and mine has worked fine this Winter. I do get occasional spike in the data, but WD will filter them out.

Here's the link to my snow depth sensor readings.

http://home.ptd.net/~mikeym/extrarealtimegraphmore.gif

And this is a link to a different graph. I need to incorporate some filter to eliminate the occasional spikes.

http://home.ptd.net/~mikeym/graphsnow1.jpg

Of course the spikes aren't showing up today - go figure.

And yes it is a real pain to set the sensitivity once the unit is mounted. Good luck.

Cheers

 :D

MikeyM

 
http://mikeymsweather.com/

Another VERY Happy WD user
Jetway Dual Core Atom D525 1.8 GHZ  2.0 GB RAM
Davis Vantage Pro wireless w/ Davis solar sensor
Laser Snow Depth Sensor LR4/Fluke 414D working in WD thanks to Brian

Offline Pieter

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Re: Ultrasonic snow depth gauge
« Reply #88 on: February 03, 2009, 07:04:55 PM »
Many Thanks MikeyM.  I'll give it a try.  I am located in upstate NY, and we have about 26 inches on the ground right now.

Warpdrive

Offline grapeghot

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Re: Ultrasonic snow depth gauge
« Reply #89 on: February 03, 2009, 09:04:59 PM »
I am thinking of using a Mini-AE myself and tried to get SensComp to send me a quote for shipping to Canada.  They couldn't tell me how much it would cost and whether they can use UPS standard or express, until I put an order in.  :?

mikeym, when you say occasional spikes, is that like several times a day?  Also, from what I have read, the sensor does not reliably report depths until there is a build up of snow that's at least several inches from the base?