I am working on developing a project for my PhD, and I am a beginner to Arduino. As a part of this project, I need a liquid flow sensor. I originally thought that I would not need to measure more than 1 l/min of flow, but I found a paper that suggested that I should be able to pump at least 1.3 l/min. I have found a few liquid flow sensors, and I was wondering if anyone has any experience with any of these or has recommendations on which one of these or other options out there to use?
For this project, I was originally considering the Sensirion SLF3S-4000B Liquid Flow Sensor; however, it can only go up to 1 l/min, and even at that, with only 20% accuracy at that high of flow according what I read in the datasheet (they also have an Arduino code library available that makes it easier to work with).
Looking around further, I found the Renesas FS1023 Liquid Flow Sensor Module. The datasheet says that it can measure from 0–3 l/min, and a typical reading accuracy of down to 2% according to Mouser and Digi-Key. However, the whole family of sensors is obsolete and thus they are limited in availability, and I can't find any meaningful Arduino code for them.
I have also come across the OOL Thermal MassFlow Sensor. The datasheet says that it can measure from 0–3 l/min, and a typical reading accuracy of 3% of measured value (depending on electronics and calibration). There is also an OOL Sensor Evaluation Kit available that makes integration easier, and it appears to be an analogue output (datasheet). However, I can't find any Arduino code examples or tutorials to work from for this sensor.
Any advice on sensors or where I can find Arduino code to learn from for these sensors? Thanks!
How accurate do you need to be? I've used those sensors that @J-M-L mentioned and I agree with the 10% figure. I ran a few tests (don't recall the flow rate) and 10% was about what I found.
If your flow rate is constant, you can also purchase a cheap flow sensor and calibrate it yourself.
Also, don't forget to check for fluid compatibility.
Without knowing what the goal is I personally would start with the cheapest easiest sensor and see how your project progresses. Since you have questions on the max flow a hall sensor (aka rotating wheel or propeller) should easily go into the 2 - 3+ liters/minute. They put out pulses that have to be counted. Counting is easy for an Arduino and there are likely many examples of counting.
I would also call the mfg tech support and talk to them. They know the most about their product and may have options your not aware of. Or they could be useless.
The OOL sensor you would need the evaluation kit as the basic sensor is not easy to measure without a reasonably sophisticated circuit. Nearly any Arduino can measure analog voltages. There are many examples of reading analog voltages.
I would NOT recommend the ESP32 type of processor board as the Analog conversion is known to be no as precise as it should be.
Thank you for the suggestion. I have wondered about these sensors as well, but I need to be able to measure down to near 0 ml/min, and the paddle wheel design isn't able to measure this low flow rate.
Thank you for the suggestion. I won't be able to use the Hall Effect sensors because the paddle wheel design doesn't measure low enough flow rate for my needs.
I do expect that my flow rate will vary. Depending on the experiment, flow rates will increase in a step-wise fashion, others will have a pulsatile flow, etc. It's definitely going to create issues with the calibration.
I have been wondering about these pumps as well, but I haven't been able to find one that I can integrate into my system and has the flow rate that I need and was planning to use a gear pump. However, I did just find one that is 1.6 l/min at 24V with a stepper motor on Amazon, and I can look at finding a transformer to go from 12 VDC to 24 VDC, so this might be a better option than I had initially planned for the pump.
Thanks for the suggestions and feedback. I am waiting to hear from the manufacturers of all of these sensors, but they haven't responded yet.
I don't think that Hall Effect sensors will work for me, as the ones that I have found don't have the range that I need (between 0–1.5 l/min). All of these sensors seem to rely on a heating element and heat sensor, and I expect that I am going to have to do some calibrating. I noticed that the OOL sensor evaluation kit has a temperature setting on it, so I am going to have to look into how to set this for my needs.
I think that I found an example code for an analogue flow sensor on GitHub, so I might start there.
I was wondering about this, but at almost $300 each, these sensors are not justifiable when there are cheaper options that cover this range of flow rates.
I'm going to be measuring flow rates of various water-based solutions (e.g., detergents, electrolytes, enzymes, deionized water, etc.). This sensor would allow me to verify how much I am actually pumping so that I can get statistical data for publications.
I completely agree with you about Sensirion's products. They look to be very professional, and they are very clear about the data on their sensors, as well as providing useful information for people who want to use their sensors with Arduinos. I really like the company and their ethos, but if I can find an easier and as accurate of a sensor where I don't have to double up on (or potentially triple up on if I need even higher flow rates), then that's what I am going to have to do.
Correction in terms, a transformer changes AC voltage to AC voltage, current is in ration with the voltage.
An appropriate power supply will convert AC to DC. There are power supplies that convert the mains to a lower AC voltage then convert that to DC but transformer will only output AC.
Here is a link to my favorite china supplier. https://www.aliexpress.us/item/3256805367649494.html? I have used these with great success. I do not connect more then 75% of there rated load. The older ones I have are now just passing 5 years, no problems.
I've found the only way to get any useful information is to call and ask to talk to an applications tech rep. Also if you get to talk to them, before hanging up ask if they would lend you an sensor. Tell them you will add their name with "kindly provided by ..." in your thesis.
Having been in product development for a long time, be careful you don't spend time and $$ creating a measurement system you think you need only to find you need something else. Again I don't know your application.
Pumping the fluid through a small, positive displacement gear pump and reading the pump's shaft rotation with an optical rotary encoder could work. What is the system pressure?
I would argue that you are partially correct. A transformer can be used with DC power to increase or decrease voltages (and the corresponding inverse effect on current), but I should have said a DC-to-DC converter.
ETA: Sorry, I should clarify further. Typically, windings around a core do create an inductor with DC power and inhibit the flow of electricity, but this doesn't mean that it is impossible to have a DC to DC transformer, as isolated DC to DC converter use transformers to isolate the two sides of the circuit from each other. In some cases, low-power DC to DC converters do use toroidal transformers. Another option is to use planar transformers that use thin sheets instead of toroidal windings.
I was planning to use a 12 V 5 A power supply using a barrel connector, and I am trying to keep things relatively contained so that I don't take up a full table top with the components (the solution reservoirs are already going to be an issue). The components in the system are going to be 5V and 12V (and two require 3.3V), and now I would be adding a 24 VDC, so I would need a triple or quadruple output power supply that can do 3.3/5/12/24VDC all in one. You might be on to something with suggesting a power supply like this though, so I will shop around a bit to see what I can find. Thanks!
I don't know what the system pressure will be, though it will be one of the things that I am measuring (I'm targeting anywhere from 10 mmHg to 120 mmHg/0.2–2.3 psi). I might be able to do it with an optical rotary encoder, but I will have to look into this further and whether I can mount one to the gear pump that I have.
I can see about giving them a call this coming week, however, they aren't all in the same country that I live in.
I am trying to be careful that I don't spend a bunch of time and money on things that I don't need, and it is definitely more challenging than I had anticipated with the various options and learning curve going into this. However, I do expect that I will need a pressure sensor and flow sensor in addition to the pump to accurately measure these parameters so that I have valid statistics for academic publication(s) of the results.