Electronics > Projects, Designs, and Technical Stuff
Volumetric measurement of liquid in transparent container
speechsupply:
--- Quote from: jpanhalt on July 06, 2018, 02:39:03 pm ---
--- Quote from: speechsupply on July 06, 2018, 11:57:19 am ---
Absolutely, but due to contamination I would prefer to avoid direct contact with liquids within the container.
--- End quote ---
Sorry, but that doesn't make sense. The "container" is made of something. You can make your probe out of the same material. How will a probe made of the came material as the container add contamination that the container doesn't add?
How did your experiments with the Sharp detector go?
--- End quote ---
Sorry for the radio silence, vacation and various other projects got in the way.
- In essence you're right. However, the liquid in the tank could be water, orange juice, gatorade, etc.. So everyday, it has to be cleaned after use.
I'm thinking, let me know if you disagree, that having a float, tube or similar internal measuring device will be difficult to clean properly.
The Sharp detector is actually looking promising. BUT only with water... cloudy substances like milk, juice, etc. is obviously different. I expected this, but seeing that water somewhat works, is actually quite nice.
Marco:
--- Quote from: speechsupply on July 06, 2018, 11:57:19 am ---Yeah it's absolutely a solution. The reason why I want to avoid weighing is primarily due to the "mechanical" aspects of building a sealed enclosure with weight cells. Tried it before, not impossible, but once someone other than me starts throwing this stuff around...
--- End quote ---
You can buy presoldered, potted strain gauges ... what kind of abuse are you expecting? Do they randomly hit stuff with a hammer? Throw fuming nitric acid onto it for a laugh?
larsdenmark:
I think capacitive sensing wins:
Non-contact capacitive liquid level sensing using FDC1004 (ProtoCentral)
Ask an Expert - How can a capacitive sensor be used in a liquid application?
Liquid-level sensing using the FDC1004 EVM
Using a pressure sensor is also possible:
Prototype Board - Pressure Sensor as Liquid Level Meter
but it is invasive, which is not what you want.
I think any acoustical or mechanical exploitation of resonanses or time of flight will be fairly complicated and expensive (unless you only need to know if the container is full or not). If the properties of the liquids differ a lot you probably need to make a lot of experimentation (or modelling) in order to make things work.
Marco:
I don't see how the capacitance sensor can be accurate for arbitrary liquids at low levels (not that weight measurement works for arbitrary liquids of course). The reference sensor needs to be fully covered to be able to compensate the signal from the level sensor AFAICS.
speechsupply:
I agree, it could change with the varying liquids. However, I have a pretty strict selection of liquids, that will go into the container. Mainly consumable (by humans) liquids.
I have the FDC1004 EVM kit now, I'll share results as I go along.
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