[engolling]

Yesterday the new laser ranging module arrived. I'm already testing.
My plan ist to build a housing and get the module out next weekend to look how it's performing. Hopefully winter will come back and give me some snow to check the correct readings. 
When everything goes fine, you will just have to buy a laser ranging sensor and a nano V3 to measure snow depth. It would be also possible to measure a water level if you point the measurement laser on a floating ball in a tube.

[f4aii]

Je vois dans le détail des messages d'erreurs qu'il a une plage de fonctionnement de -20° à +40°, ce qui peut poser des soucis l'été. En principe, à -20° et en dessous, il ne neige jamais sous nos latitudes.
Le soucis peut se poser l'été mais en ventilant le boitier, çà ne devrait pas être un problème.

[engolling]

Hello f4aii,

thank you for the error table.
With the help of the French I learnt at school and google translator I could understand your concerns.

I think I could simply disable the sensor in summer, because there won't be snow anyway. If you use the system for some height, or distance measurement it would be necessary to have good ventilation. But I will check out, when the sensor disables itself.

Merci beaucoup 

[f4aii]

Sorry, I did not copy the correct window, I write my texts in google translation. I am not sure of writing correctly in English and very often the readers translate in their language, which makes 2 conversions and it multiplies the misunderstandings if it is badly translated.

I wrote: "I see in detail the error messages that it has an operating range of -20 ° to + 40 °, which can be a problem in the summer. In principle, at -20 ° and below, it never snows in our latitudes.
The trouble can arise in the summer but by ventilating the case, it should not be a problem."

[f4aii]

https://fr.aliexpress.com/item/50M-DIY-R....13.cz7UPW

i see this, it's less expansive compared to the others. they are identical

[AllyCat]

they are identical

Are you sure?  I don't think it has an RS232 (serial) interface and it is only specified for operation down to 0 degrees C (and 3 mm resolution). 

Even if searching for "RS232 laser rangefinder" you need to be very careful because one is listed as "NO RS232 function".  

Cheers,  Alan.

[engolling]

Concerning the distance meter f4aii proposed, I also think it's another one.
I tried different range meter to get some useful readings out of them, but in my opinion it's not worth it cause you save 15 Euros for searching around for hours.

But back to topic, yesterday, since we were expecting some snow I made my range meter ready with an Arduino mega and an SD Card memory and put it outside to get a proof of concept that this device will measure the snow properly.

It had to be very quick and got even more dirty, but you can see by yourself...


  

Here you can see both range meters in my test setup:

[engolling]

And this is the view from inside the house today:



I'm validating the measurement later that day, but I expect that everything will be fine. After that I will start to finish the software and to make a PCB with an Arduino Nano, voltage regulator, level shifters and tare button so it can be used for each distance measurement.

[engolling]

Since I didn't manage it to read the stuff on the SD card the last weekend it's is hopefully still writing.
My new plans are to check it the first weekend in march and I still hope to get a positive result.

Then I will decide how the further steps will look like and to do everything to have a working sensor with WeatherDuino for the next winter 2018/19.

[engolling]

Today I was able to compare the readings of my snow depth measurement. Unfortunately we did not have much snowfall so the signals are not changing very much.

Here you can see the "old" measurement:



And here you can see the readings of the new laser:


Please note that the existing laser is filtered with an 20min median filter, so readings are smoothed. Moreover the sensors did not measure at the exactly same position.

But you can see the following things:

• The new laser has faulty measurements the the beginning. They toggled between an error value and over 1m to much. But this could be a result of my bad setup and even it was not, this could be filtered easily.
  
• The old laser reacts to sunlight with a slightly higher reading of about 5mm
  
• The new laser has a lower reading of about 10mm. That's not so nice but altogether it's ok.
  

So my aim is now to make a PCB with an Nano, voltage regulator and level shifter, to provide the readings to the TX station via I2C.
The software interface will have to be defined.