Yes. a spring connected to an adjusting screw. You tighten or loosen the thumb screw in order to calibrate the scale.
View attachment 354456
The thumb screw (nut actually) can be adjusted to tighten the pull of the spring or it can be loosened to relax the tension on the spring. The flat plate is some sort of mounting bracket. Since I don't have a rig to draw out I just put the flat plate there to indicate what the screw is pulling against. Actually I see a slight mistake; no washer. Oh well. You've stated you want to go back to the weight system. Sorry I couldn't be of more help.

Ahh, I get it now. So the diagonal lines is the same screw going through a nut (horizontal lines)..I was thinking 2 different devices on opposite sides of a mounting plate...My bad (early morning brain issues)

So a screw, adjusted by a nut, which changes the tension level on a spring. This part sounds simple enough. The other side of the spring connects to some sort of a beam?, which is connected to an actuator arm which connects to a potentiometer. I'm not sure how I would connect all those together. And where my load would go in relation to these parts.

While a weight-based solution is the goal, that weight doesn't necessarily have to be determined by a load cell. If I can determine that weight based on the position (and resultant output voltage) of a potentiometer, that works for me! Would just need some examples of what kind of parts I would be looking for and how they connect to each other. As I say, I've got the book knowledge of physics, but the machanical mind of a 5 year old. This comes from years of studying material from physics books/computer screens, but not actually performing experiments to make real life examples of the forces I'm learning about.

 

That rainfall equivalent is what I would be aiming for.

So there's a bit more going on here than simply a rain gauge. Understood.

All the electronics involved could still operate at below freezing temps (at least as far below freezing as my climate gets, which is usually not much below freezing)

I wasn't thinking so much of the electronics as the moving parts. They might be fine in the daytime, but if you have daytime snow that leaves water behind, and temps drop below freezing at night, things could get bound up with ice. (Temperatures here drop below freezing for weeks at a time, even during the day, so I have a much different point of reference.)

The suggestions now being made about using a potentiometer, is an alternative way to effectively make a strain gauge while avoiding the data drifts associated with standard cheap load cells.

AFAIK, most strain gauge creep is at zero, not in sensitivity, so couldn't you just re-zero in software after every emptying event? You might have to do that anyway, since all the water may not always be evacuated from the system.

 

This wasn't mentioned yet, I think, but I had concerns about the resolution from the first post. In the non electronic sense.

0.01" = 0.254mm

That is very little. So little that evaporation and surface tension of water would probably account for much more than several percent accuracy, especially when the rain is not intense. Drizzle or light rain would probably barely register with accuracy tens of percent off.

I guess if he keeps the down pipe narrow it won't be as much of a problem. The collector mouth could still be wide.

 

That rainfall equivalent is what I would be aiming for. Then we can use that liquid equivalent with the physical depth of snow on the ground (either manually measured with a ruler or better yet electronically with something like a laser or ultrasonic distance sensor) and then we use those values to calculate the density of snow by means of "physical snow depth to liquid equivalent ratio"..

With a manual gauge, snow accumulates inside the collection bucket. We then bring the bucket inside and weigh the snow on a kitchen scale (or either let it melt and pour into the gauges inner beaker tube) to get the liquid equivalent. Then we go out and measure the depth on the ground with a ruler to get our physical depth. Then divide the values to get the snow/liquid ratio for snow density. It works, but requires a lot of effort, is time consuming and does not give you real time data..

With tipping bucket rain gauges, we wrap the gauge with heated high resistance cable to warm the collection bucket so the snow melts inside the gauge then flows into the tippers like rain. Problem here is 1. The accuracy issues of tipping buckets...2. It can take a while to melt heavy snow using low heat that's barely above freezing...3. If you use high heat to quickly melt the snow, a lot of evaporation/sublimation occurs (tried it and you can actually see steam/fog rising out of the top of the gauge)...

With my proposed design, I would be able to get the liquid equivalent in real time through weight, regardless of snow rate, without having to wait on it to melt or risk evaporation. With a depth sensor (ultrasonic, et.al), I could get a real time depth and let the script calculate my real time snow/liquid ratio.




That part is a work in progress, but ideally I would make the design to limit the gap between the funnel and outer bucket to limit the amount of rain and snow that reaches the underside of the funnel. This could be done by adding a small downward underhang on the edges of the funnel and the bucket height being higher than that underhand (or something added to the bucket that makes effectively makes it's surface higher than the underhang)...In image below, gray being the underhang wrapping the edges of the funnel that shields precip from the funnel underside.





All the electronics involved could still operate at below freezing temps (at least as far below freezing as my climate gets, which is usually not much below freezing)...And for snow removal, it's fairly rare in my area so could manually dump it or wait for it to melt on it's own after a day or two. Alternatively, I can wrap the underside of the funnel and inner collection tube with high resistance cable (much like I do to heat the tipping buckets) but only power it with a manual switch after the snow ends and I'm ready to empty.



To my understanding, what I was looking to get essentially was the guts of a cheap digital scale...This is an example of what I was originally plannning:

https://www.amazon.com/ShangHJ-Digital-Weighing-Portable-Electronic/dp/B09VYVRQD5/

Connect one of the load cells to an included HX711 amplifier, then connect the ampt to a microprocessor (such as an Arduino or Raspberry PI)....But compensating for creep with a continuous (but changing) load is where the problem comes in...Taking the guts out of a digital scale should essentially give me the same parts (load cell and amp) with the same drift issues as it's related to the metal of the load cell deforming under constant load.

The suggestions now being made about using a potentiometer, is an alternative way to effectively make a strain gauge while avoiding the data drifts associated with standard cheap load cells.

Couldn't you use a heated system? This would prevent icing and also convert snow to water.
To figure out the water to snow-level constant you may have to actually measure the height of some snow that falls on some known area.

 

I wasn't thinking so much of the electronics as the moving parts. They might be fine in the daytime, but if you have daytime snow that leaves water behind, and temps drop below freezing at night, things could get bound up with ice. (Temperatures here drop below freezing for weeks at a time, even during the day, so I have a much different point of reference.)

That's pretty much the same issue with the tipping buckets, since they're moving parts. In arctic areas, people often run the gauge heater (usually a high resistance cable or an incandescent light bulb) all winter to keep the gauge from freezing up. In some cases, they include a thermostat to maintain it at a desired temperature and save electricity. The same would be required with this invention if used in an area with prolonged freezes. In my case, I would probably wrap the insides with heated cable and just manually power it on the rare occasions that I need it.

AFAIK, most strain gauge creep is at zero, not in sensitivity, so couldn't you just re-zero in software after every emptying event? You might have to do that anyway, since all the water may not always be evacuated from the system.

Definitely would re-zero after every empty and probably on a regular time interval between empties. Problem comes during rain when values start drifting. My initial thought was to frequently re-zero (even during rain), with the script data logging the observation before each re-zero and knowing to add each previous value to the current measurement. Example, say I data log every 10 minutes and re-zero 5 seconds later.... Suppose it starts raining at 12:13pm, my data log would look like this

12:00pm - 0 grams
12:10pm - 0 grams
12:20pm - 5 grams
12:30pm - 4 grams
12:40pm - 8 grams
12:50pm - 2 grams

My live daily total is (live weight + sum of all previously logged weights of the day)

Now it's 12:53pm and my current weight is 1 gram.....My daily total would be current weight (1 gram) + 0 + 0 + 5 +4 +8 +2 = 20 grams.....If using a 12" diameter gauge, where 18 grams = 0.01", it would be Current total (20) * 0.01 / 18 = 0.011" daily rain.

This could work, providing my readings are stable and drift is less than 1 gram per 10 minutes. But if the output is noisy and unstable, then this method could introduce more error than simply letting it add up without re-zeroing every few minutes.

 

Couldn't you use a heated system? This would prevent icing and also convert snow to water.
To figure out the water to snow-level constant you may have to actually measure the height of some snow that falls on some known area.

Heated systems melt slowly at slightly above freezing temps so your data comes at a delay. Higher heat levels will melt it quicker, but cause significant evaporation. Weighing without melting first gives you the data in real time with no concern of evaporation.

 

So a screw, adjusted by a nut, which changes the tension level on a spring. This part sounds simple enough. The other side of the spring connects to some sort of a beam?, which is connected to an actuator arm which connects to a potentiometer. I'm not sure how I would connect all those together. And where my load would go in relation to these parts.

There are several holes you could hang your bucket from. As it gets heavier the beam dips down, moving the center wiper of the pot, thus you have your weight.

In my second drawing I showed, rather than a pot, an interference wheel. As the bucket gets heavier the beam drops and the gear turns the wheel. A computer chip counts how many times. From that you calculate your weight. As for draining the bucket when cone, best someone else answers

 

There are several holes you could hang your bucket from. As it gets heavier the beam dips down, moving the center wiper of the pot, thus you have your weight.

In my second drawing I showed, rather than a pot, an interference wheel. As the bucket gets heavier the beam drops and the gear turns the wheel. A computer chip counts how many times. From that you calculate your weight. As for draining the bucket when cone, best someone else answers

Hmm, a hanging design kind of complicates things a bit, since only parts of the design gets weighed, including the area at the very top where no obstructions can be above it. So I would have to connect the funnel, solenoids and inner tube together, then hang from the middle of it all inside the bucket. Would be much easier if the scale could be at the bottom with the measured area sitting on it. Like if the weight sitting on a plate could pivot an arm upward (more weight = more upright the arm goes) and the pot adjust with the angle of the arm. Not sure if that could be done, though.

 

No plan is perfect.

 

Hmm, a hanging design kind of complicates things a bit, since only parts of the design gets weighed, including the area at the very top where no obstructions can be above it. So I would have to connect the funnel, solenoids and inner tube together, then hang from the middle of it all inside the bucket. Would be much easier if the scale could be at the bottom with the measured area sitting on it. Like if the weight sitting on a plate could pivot an arm upward (more weight = more upright the arm goes) and the pot adjust with the angle of the arm. Not sure if that could be done, though.

Beat that, Rube Goldberg!

Everything could be weighed with the scale at the bottom, per your snow weight illustration in post #75, resting the PVC collection pipe on the scale beam instead of the load cell. It doesn't matter which way the beam goes when more weight is added -- think the suggestion from Tonyr1084 in post #71.

Not to throw a wrench into the weight-based gauge, but... You mentioned using laser or ultrasonics to measure the height of snow accumulation. Why not use an ultrasonic device to measure water level in your collection container? You'd still need the separate weight measurement (which could also be done with an ultrasonic sensor**) for your SWE calculations, but even then, it seems the entire system would be simpler, more reliable, and more accurate. And you could use the same code for reading all of the sensors, changing units and scaling as appropriate.

**I hope you don't have a dog.

 

Everything could be weighed with the scale at the bottom, per your snow weight illustration in post #75, resting the PVC collection pipe on the scale beam instead of the load cell. It doesn't matter which way the beam goes when more weight is added.

This comment inspired me to draw another picture. Take it for what it is. Or leave it. Choice is yours, but here's yet another potential solution:
View attachment 354504
Whether you use a pot or an interference wheel, the movement can be measured by how much the vessel deflects the scale. The spring and pot can be located anywhere along the beam. Closer to the vessel will render a greater accuracy and the spring can be located where it best suits the closest approximation of anticipated weight. The thumb wheel can bring you into the final calibration.

I think I've offered all I can. From here you can further modify the thinking. You can extend the upper beam even further and move the pot out along the beam to increase accuracy. Choosing the right spring tension can also improve sensitivity.

Hope this helps you achieve your quest.

 

Heated systems melt slowly at slightly above freezing temps so your data comes at a delay. Higher heat levels will melt it quicker, but cause significant evaporation. Weighing without melting first gives you the data in real time with no concern of evaporation.

But how do you figure out what the snow to water factor is every time when it can change with the crystal?

 

But how do you figure out what the snow to water factor is every time when it can change with the crystal?

Mass is the only thing that matters. It's assumed that mass of unmelted snow = mass of the same snow, melted, which is what the system is calibrated for. This gives you the equivalent rainfall ("snow water equivalent", or SWE) measurement.

 

Mass is the only thing that matters. It's assumed that mass of unmelted snow = mass of the same snow, melted, which is what the system is calibrated for. This gives you the equivalent rainfall ("snow water equivalent", or SWE) measurement.

If it is a weight measurement then that is probably good, but if it is a depth measurement then it's not as good.

 

But how do you figure out what the snow to water factor is every time when it can change with the crystal?

Werecow is correct. A sample of frozen snow has the same weight after it's melted to water. The density canchange throughout the duration of the storm, as temperatures change, flake size changes, etc....The ratio may start out with 8" snow per 1 inch of rain while temperatures are near freezing, and end at 25 inches of snow per 1 inch of rain as the air is much colder/drier, etc. One method is to take an overall average of the whole event (take the full depth of snow, weight it (or melt it and measure in a beaker), then divide. You'll have your average of the whole event. Alternatively, you can measure at different time intervals during the event. Say, you take a measurement once per hour, weigh or melt that sample and calculate the ratio. Next hour, take a new sample and do the same. That will show how your density (snow/liquid ratio) changed by the hour throughout the storm. With my proposal, you could calculate that density by the minute (or as often as you want) by comparing added weight to added depth over any given time frame.

Not to throw a wrench into the weight-based gauge, but... You mentioned using laser or ultrasonics to measure the height of snow accumulation. Why not use an ultrasonic device to measure water level in your collection container? You'd still need the separate weight measurement (which could also be done with an ultrasonic sensor**) for your SWE calculations, but even then, it seems the entire system would be simpler, more reliable, and more accurate. And you could use the same code for reading all of the sensors, changing units and scaling as appropriate.

I was actually considering using laser or ultrasonic as a temporary work around to measure rain depth earlier on in this thread (Probably a few pages back, before you joined)...There was a few issues. One being that it would require melting snow first in order to measure it's liquid depth. Other issues I was running into was beam width, size requirements and accuracy range.

The accuracy rating on these budget laser/ultrasonic sensors is often +/- 2 cm. In order to measure to the nearest 0.01" with these, I would need to magnify my rain so that each 0.01" increased to about 2 cm in depth. One example being an 8 inch diameter funnel to collect the rain which narrows into a 1 inch diameter pipe. That's a 64X surface area magnification, so 0.01" of rain collected in the 8 inch funnel would be 0.64" (16mm) deep inside the 1 inch pipe. That's pretty close to what I would need to assure accuracy...But all of these "laser time of flight" sensors I was finding seemed to have a beam width of 25 degrees, which would not work in a 1 inch diameter pipe (expanding beam would quickly hit the edges of the pipe and reflect back). Even aiming it down a 12 inch long pipe, the beam width would be over 5 inches wide at the end . So I would either need a much finer beam width (which I was having trouble finding) or either I would need to make my inner pipe diameter about 6 inches wide and 12 inches long....In order to maintain that 64X magnification using the now 6 inch diameter pipe, my collection funnel would be to be 48 inches in diameter. A lot bigger than I was hoping for.

For ultrasonic, it would not matter if the field of view struck the side of the pipe, so long as it's a smooth surface. But if there's any water droplets on the sides of the pipe (and it likely would after emptying or from condensation), those droplets could be reflective sources. This is a known issue in plumbing when using ultrasonic to sense the water level in a pipe.

There's also issues with temperature compensation on ultrasonic, as well fogging on the sensor (ultrasonic or laser), so some heating source would likely be required. Granted, this would also be required if using these methods for snow depth.

**I hope you don't have a dog.

No, but I do have some concerns about birds, squirrels and other wildlife climbing into the gauge and/or deciding it would make them an ideal toilet.

This comment inspired me to draw another picture. Take it for what it is. Or leave it. Choice is yours, but here's yet another potential solution:
View attachment 354504
Whether you use a pot or an interference wheel, the movement can be measured by how much the vessel deflects the scale. The spring and pot can be located anywhere along the beam. Closer to the vessel will render a greater accuracy and the spring can be located where it best suits the closest approximation of anticipated weight. The thumb wheel can bring you into the final calibration.

I think I've offered all I can. From here you can further modify the thinking. You can extend the upper beam even further and move the pot out along the beam to increase accuracy. Choosing the right spring tension can also improve sensitivity.

Hope this helps you achieve your quest.

Definitely helpful! I appreciate your efforts in drawing these designs up! Whether or not I can figure out how to replicate them with actual parts is a different story, but I would be willing to give it a try as it's sparked my interest. I'm not familiar with interference wheels or how I would get their output to a microcontroller. A voltage monitor for a pot's output would probably be much easier for me to figure out. I have used pots for controlling fan speeds and such, so I'm more familiar with them. Not sure if there's a certain type of pot that I would need or if any would work. A certain type of beams that I'm looking for, or if any piece of metal with holes would work. I just don't know where to start in terms of shopping for parts, as I've never tried to make anything of that nature before.

In reality, I probably need to just buy a load cell first and test it rather than assuming it won't work. It's cheap and it's plug and play ready. If by chance it can maintain the needed accuracy with only minor calibrations, then problem solved. If my assumed unreliability proves true, then I'm only out of a few dollars and I'll know for sure that I need to pursue building something like your design. Clearly, it's going to be a learning curve for me to figure out how to make a weighted beam turn a pot.

 

I'm not familiar with interference wheels or how I would get their output to a microcontroller.

An interference wheel is simply a clear plastic wheel with blacked out spots (as depicted). They can also be a solid wheel with holes to allow a beam of light to pass through. There are other types of wheels as well. The one I drew up can only count pulses. Doesn't matter which direction the wheel is moving, all it does is pass light, block light, pass light, block light - and on and on. Give ma a while and I'll draw one that counts up when spun in one direction and down in the other.

The beam of light can act as a signal to a counter. Every pulse of light thought the open window can produce a logic level high, which a counter would see that as a clock pulse. The Bi-Directional type has two inputs. A goes high, then B goes high, then A goes low, then B goes low. There are times when both A & B are high and when both A & B are low. For that type you'd need an encoder chip. That's getting a little beyond my skill level, so I won't try to advise you on that. Someone would surely come along and say "Tony's wrong." Not that I am worried about being told I'm wrong - when I'm wrong that's when I learn the most.

Anyway, give me a while and I'll bang out another picture.

 

Wheel A is the same wheel in the previous drawings. Wheel B is the sort that counts UP or DOWN.
Sensor A consists of a single LED inside a housing with a small opening, and a single photo sensitive transistor (or other photo device). When the light from the LED strikes the transistor - the transistor turns on. Whatever signal is at the collector is passed through to the emitter. A counter will see that as a single clock pulse, or a single count. Drawing a sensor for B is more complex and would likely be difficult to follow. Just that there's likely to be two LED's and Transistors. Basically a dual sensor.
View attachment 354573
I can't see Wheel B being of much use to you. It's not likely that you'll need to count both up and down. Just count as the weight increases. When the water is drained you simply reset the counter and continue on. You can even use a counter to count the number of times the bucket is emptied. Wheel B is typically used in printers where the head has to be moved in one direction or another, and the printer needs to accurately count where the head is.

 

Werecow is correct. A sample of frozen snow has the same weight after it's melted to water. The density canchange throughout the duration of the storm, as temperatures change, flake size changes, etc....The ratio may start out with 8" snow per 1 inch of rain while temperatures are near freezing, and end at 25 inches of snow per 1 inch of rain as the air is much colder/drier, etc. One method is to take an overall average of the whole event (take the full depth of snow, weight it (or melt it and measure in a beaker), then divide. You'll have your average of the whole event. Alternatively, you can measure at different time intervals during the event. Say, you take a measurement once per hour, weigh or melt that sample and calculate the ratio. Next hour, take a new sample and do the same. That will show how your density (snow/liquid ratio) changed by the hour throughout the storm. With my proposal, you could calculate that density by the minute (or as often as you want) by comparing added weight to added depth over any given time frame.



I was actually considering using laser or ultrasonic as a temporary work around to measure rain depth earlier on in this thread (Probably a few pages back, before you joined)...There was a few issues. One being that it would require melting snow first in order to measure it's liquid depth. Other issues I was running into was beam width, size requirements and accuracy range.

The accuracy rating on these budget laser/ultrasonic sensors is often +/- 2 cm. In order to measure to the nearest 0.01" with these, I would need to magnify my rain so that each 0.01" increased to about 2 cm in depth. One example being an 8 inch diameter funnel to collect the rain which narrows into a 1 inch diameter pipe. That's a 64X surface area magnification, so 0.01" of rain collected in the 8 inch funnel would be 0.64" (16mm) deep inside the 1 inch pipe. That's pretty close to what I would need to assure accuracy...But all of these "laser time of flight" sensors I was finding seemed to have a beam width of 25 degrees, which would not work in a 1 inch diameter pipe (expanding beam would quickly hit the edges of the pipe and reflect back). Even aiming it down a 12 inch long pipe, the beam width would be over 5 inches wide at the end . So I would either need a much finer beam width (which I was having trouble finding) or either I would need to make my inner pipe diameter about 6 inches wide and 12 inches long....In order to maintain that 64X magnification using the now 6 inch diameter pipe, my collection funnel would be to be 48 inches in diameter. A lot bigger than I was hoping for.

For ultrasonic, it would not matter if the field of view struck the side of the pipe, so long as it's a smooth surface. But if there's any water droplets on the sides of the pipe (and it likely would after emptying or from condensation), those droplets could be reflective sources. This is a known issue in plumbing when using ultrasonic to sense the water level in a pipe.

There's also issues with temperature compensation on ultrasonic, as well fogging on the sensor (ultrasonic or laser), so some heating source would likely be required. Granted, this would also be required if using these methods for snow depth.



No, but I do have some concerns about birds, squirrels and other wildlife climbing into the gauge and/or deciding it would make them an ideal toilet.



Definitely helpful! I appreciate your efforts in drawing these designs up! Whether or not I can figure out how to replicate them with actual parts is a different story, but I would be willing to give it a try as it's sparked my interest. I'm not familiar with interference wheels or how I would get their output to a microcontroller. A voltage monitor for a pot's output would probably be much easier for me to figure out. I have used pots for controlling fan speeds and such, so I'm more familiar with them. Not sure if there's a certain type of pot that I would need or if any would work. A certain type of beams that I'm looking for, or if any piece of metal with holes would work. I just don't know where to start in terms of shopping for parts, as I've never tried to make anything of that nature before.

In reality, I probably need to just buy a load cell first and test it rather than assuming it won't work. It's cheap and it's plug and play ready. If by chance it can maintain the needed accuracy with only minor calibrations, then problem solved. If my assumed unreliability proves true, then I'm only out of a few dollars and I'll know for sure that I need to pursue building something like your design. Clearly, it's going to be a learning curve for me to figure out how to make a weighted beam turn a pot.

For the reply you responded to that I wrote, I already addressed.

 

Wheel A is the same wheel in the previous drawings. Wheel B is the sort that counts UP or DOWN.
Sensor A consists of a single LED inside a housing with a small opening, and a single photo sensitive transistor (or other photo device). When the light from the LED strikes the transistor - the transistor turns on. Whatever signal is at the collector is passed through to the emitter. A counter will see that as a single clock pulse, or a single count. Drawing a sensor for B is more complex and would likely be difficult to follow. Just that there's likely to be two LED's and Transistors. Basically a dual sensor.
View attachment 354573
I can't see Wheel B being of much use to you. It's not likely that you'll need to count both up and down. Just count as the weight increases. When the water is drained you simply reset the counter and continue on. You can even use a counter to count the number of times the bucket is emptied. Wheel B is typically used in printers where the head has to be moved in one direction or another, and the printer needs to accurately count where the head is.

So if the wheel spins a little and 10 holes pass the LED, it will trigger 10 pulses to the counter. I guess in a broad sense, it's a somewhat similar process to how the reed switch in the tipping bucket gauges tells the counter how many times the tipper has passed.

I have no clue how I would reproduce all of this with hardware, but the idea behind it makes sense!

 

The wheel can move slowly. Every time a beam is established there's one clock pulse. You don't have to spin it like a top.

The approach I'm envisioning is having the sensor and wheel. Those wheels come in many configurations. The illustrations have 33 to over 50 windows. You can get them with hundreds of those marks. They're much smaller.

So the wheel slowly rotates as the weight of water in the bucket opposes the spring tension. As the weight increases you get a pulse every time a window opens. The electronics would consist of something like a decade counter and an encoder that would produce digits. For higher number counts you would need two decade counters and as many encoders as digits you want. Or, since microprocessors are NOT my forte you could program a controller to count the openings and give you a readout. When the bucket is drained you can disable the counts until the bucket has fully emptied and the weight of the bucket has returned to the zero point. OR you can use a large enough capture vessel, one that won't need to be reset until rain tops 20 inches. When the storm is past you reset the system and measure again.

As for measuring snow - that's a whole different animal. Or maybe not. If you're measuring the weight of the apparent water weight then inches of snow won't matter to you. 10 inches of snow can have the same weight as 1/4 inch of snow. Just depends on how wet the snow is.