Anyone familiar with this 3 pin optical liquid level sensor?

There's also a similar 4 pin version, but I can't find anything about this 3 pin version. I've tried applying 5V to the red and black pins and It showed 5V on the white pin. it seems to be an active low signal, but I just want someone to confirm that because sometimes it doesn't show any output.

Also, initially it drew over 600mA for a while and then it stopped. I'm not sure if I destroyed it by using it incorrectly.

Any help would be appreciated. Thanks.

Edit: I was able to find this. it is a bit different and doesn't explain the initial current draw.

could you add a link to a datasheet ?

Unfortunately, I couldn't find any datasheet. I bought it thinking it was the 4 pin version. you can see the 4 pin version here, then the seller updated the listing (probably after I messaged them about that) with the 3 pin version. you can see it here, but I can't see anything useful.

I've asked the seller and I couldn't get anything useful.

based on what you described in your messages, i must admit that i'm also out of ideas, I think I would have taken the same approach as you...

did you just buy one single such sensor ?

Oops. Doesn't sound good to be honest. That's 3W, but the Aliexpress page mentions < 60mW power consumption at < 12mA. 99% certain to be fried.

Yes, only one, just to test it, because I wasn't sure if that's going to be suitable for my project. I was going to use it as a part of a dry run protection system. In this case it was a good decision since the seller sent me the wrong item. I already got a refund, but this version is better (if I can get it to work), because then I won't need the extra cables & resistors required for the 4 pin version.

Yeah, It shouldn't be nowhere near that. I initially set the current limit to 50mA and my power supply went into current limiting mode. Then I gradually increased the current limit and it went up to around 600mA and then nothing.

Sorry about the deleted post. didn't know how to quote

Well, that baffles me a bit, to be honest. You went ahead and deliberately blew it up. That's very odd indeed!

Well, yes, you could say it was deliberate. there were no instructions & no datasheet. I couldn't find any diode junctions on any of the pins. I could have used a different set of pins, but red and black seemed a good choice. it may very well be a defective unit.

I'll post here if there's any update.

Hi @new-arduino-account

Do you have a DMM?

RV mineirin

Yes, I do. Anything you want me to check?

I have an update. I was able to find this. I think it's a variation of FS‐IR02 sensor.

According to that my setup should be correct, right? It still doesn't explain the initial current draw. It might be a faulty unit.

Hi,
This might also help;
https://www.elecrow.com/wiki/index.php?title=Crowtail-_Non-contact_liquid_level_sensor

Tom... :smiley: :+1: :coffee: :australia:
SORRY WRONG TYPE OF NON CONTACT....

Hi, @new-arduino-account
Your image in post #1, what piece of paper is the sensor laying on?
Did it come with the sensor?

Thanks.. Tom... :smiley: :+1: :coffee: :australia:

Thanks. Yes, it's a different one. FS‐IR02 should be the correct one.

Yes, it's the label of the package. I used the same image I sent to the seller as proof.

Hello, I have the same issue. Ordered the 4 Wire version, received the 3 wire version.
I found via Bangood (https://www.banggood.com/WMSR-OL-60B-Liquid-Level-Sensor-Water-Dispenser-Water-Level-Gauge-Liquid-Level-Sensor-Module-p-1884753.html?cur_warehouse=CN) this type as WMSR-OL-60B, but could not find anything more on this sensor itself.
I tried following: Red to +5V, Black to Gnd, measure White. Current drawn is approx 9mA. The white wire measures +5V when sensor is open, remains +5V when sensor is submerged in water and close to 0V when sensor is completely shaded (close your hands around it). It act as an LDR, not as a water level sensor. I asked the supplier (Aliexpress supplier) to provide the datasheet, or if not possible - to refund. The 3 wire looks promising, but I am afraid it needs something more than just a power supply.

Hi, I also received the three wire (non-prism) sensor by mistake after ordering the 4 wire. However, I think that all that has changed from the 4 wire version is that the blue and white wire have been combined to the red wire on the 3 wire version. Hopefully the diagrams explain more clearly...

The 3 wire sensor (I think!) combines the blue and white wires into the red wire but everything else seems to be the same - it works on the breadboard when i test it anyway!!

Hope this helps! No guarantees :slight_smile:

1 Like

Hello, I do not think so ! If this would be the case, then we would have to be able to measure a diode between the red (Anode) and black (Cathode) side. I have both the 4 and the 3 wire version available and measure the diode (approx 1.2V) between Blue (+) and red(-). On the three wire version, there is no combination in which to measure any diode.
If someone would have a deatasheet this would be helpfull. I requested a datasheet from the supplier who also 'accidently' delivered 3 wire versions instead of 4 wire ones, but never received them. I received reimbursement for the wrong versions.

Just to answer Yves, I definitely get 1.062v between red and black in diode test mode (Fluke 87V) indicating the ir emitter.

Hi Yves, just a possibility but if as you stated in an earlier post you connected Red to 5V and Black to GND, with no current limiting resister, you may have blown the ir led, hence why you do not get a reading in diode test mode??

Hello, Your conclusion might be correct. I remember having at first connected the red wire via a resistor of 4k7 to +5V, having GND at the black wire. I could not measure any change on the white wire (dry/wet). Most probably, as you mention - I will most certain have blown the IR LED. I used also a FLUKE 87 in Diode mode, but as you point out - a blown LED will measure nothing ...
Strange that no supplier is willing to provide a data sheet, this would have made lifr much easier (and introduced savings). Congrats for your analysis !!!