Ultrasonic snow depth gauge

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

its a mv ADC (battery voltage sensor)
e.g like the leaf or soil moisture sensor

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
:slight_smile:

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

Hi, great information.

Where are you?

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

:smiley:

MikeyM

Really super, as says MikeyM, for my case it works correctly.
Serge

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

:smiley:

MikeyM

Very nice. I hope it does well.

Mark

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

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.

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

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

:smiley:

MikeyM

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

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?

Yes, I’d say occasional spike - some days none and other days quite a few. Brian has WD filtering the data so that rarely a spike will show up in the WD extra sensor graph. The GraphWeather graphing program that I’m using doesn’t have any filtering so that’s where my occasional spikes show up. I haven’t had time to go out and tweak the sensitivity setting and that might fix the problem. So far this Winter it has been very reliable and I’m happy with the performance. The Sensor that I’m using measure from .5 feet to 20 feet, but sensor allows the max and min distance to be set at either the high (5 volts ) or low (0 volts ). I have my sensor set up for 50 inches so 0 volts is no snow and and 5 volts is 50 inches. With this setup the sensor will start sensing the snow almost immediately. With that said it does depend on the density of the snow. Very light fluffy snow is much harder for the sensor to detect that heavy wet snow. I would say that dry fluffy snow will take a couple of tenths before it starts to get reported. Hope that helps. I also think that the spikes are a 1-wire problem and not a Senscomp sensor problem. I haven’t had time to hook an oscilloscope up and monitor the line. Like friend told me “I’m so busy since I retired that I don’t know how I found time to go to work”. Guess I’m just good at wasting time.

Cheers

:smiley:

MikeyM

I have a silly question: how do you connect your non standard sensors to a VantagePro, i.e. what inputs are you using?
I couldn’t find any spec about the input signal.
E.g. the leaf wetness sensor or ground temperature sensor inputs: are they 4…20mA, or 0…10V or what?
How do you calibrate and convert? Externally in your weatherstation software?

Before even thinking about a solution for snow height measurement I’d like to get a better understanding about how to interface and input/convert the data.

And then I might try some of your suggestions or others (like something based on laser distance metering)

Thanks
Hans

Hans

The snow sensor is interfaced to WD using 1-wire. Basically the analog output from the ultrasonic sensor is applied to the Vad input of a HobbyBoards humidity board minus the humidity sensor and the the signal is fed to a 1-wire adapter that can either be a serial (RS232) adapter or a USB 1-wire adapter then WD will read the input. There is no interface or anything connected to the Davis Vantage Pro.

Hope that helps.

Cheers

:smiley:

MikeyM

Just a quick question… Is this system available in kit form for sale and if so how much is it? I would be interested in possibly obtaining this if it works well with a Lacrosse WS2310 setup.

Mike,
now that I searched a bit in the forum I understand what hobbyboard, WD, WDL and 1-wire means…
I do not use WD but Davis’ standard software (Weatherlink) and a German program (Wetterstation).
My intention is, do connect/interface some kind of sensor to the remote sensor units I’m already using. There are available inputs (e.g. leaf wetness sensor, ground temperature, …).
But I do not know the specification of that (non serial, non 1-wire) analog interface.
I hoped somebody could help me and did something similar already.

Thanks for the feed back anyhow; helped me to learn something new :wink:
Regards
Hans

http://www.hsn.de/my-weather/WS-Win/start.html

Hi John

No this is not available in a kit. You have to round up the parts and put it together yourself. The best source of info is Steinar’s site in Norway. Here’s the link: http://voksenlia.net/met/snow.php
Basically the sensor is from Senscomp and the board is the temp/humidity board from HobbyBoards minus the humidity sensor. Eric is more than happy to supply the board minus the humidity sensor.
Hope that helps.

Cheers

:smiley:

MikeyM