Inside a washing machine water level transducer. (schematic)

In a previous video I took apart my new washing machine to show how modular it was inside. I thought the water level switch was the usual multi-switch pressure transducer, but a few viewers mentioned that it is an inductive transducer that sends pulses to the controller to indicate the water level.
So I went online and bought a used one so we can take it to bits and see how it works.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
www.bigclive.com/coffee.htm

[@anononomous]

Before Big Clive (BBC?) I couldn't have even imagined being excited by the prospect of watching a video called "Inside a washing machine water level transducer. (schematic)" :-)

[@jusb1066]

next week 'clive does the washing up'

[@Fifury161]

Same - it's gotta be down to his presentation style!

[@andruloni]

+Jusb1066 In this video he would share some simple washing-up advice you would never imagine worked and say it's pretty common among his circles

[@CactusJackSlade]

Great video! Based on this video I did a HACK by cutting a hole in the top to access the pressure adjustment screw and now we have the proper amount of water (about 20% more than factory) in our machine 🙂

[@bigclivedotcom]

Keep in mind that modern front loaders deliberately use very little water at the start of the cycle as they only intend to make the clothing wet. That increases the activity of the detergent and also increases the friction as the drum tumbles the saturated items so they rub against each other as opposed to just floating about in water. After that the machine uses much more water in the rinse stages. The machine will initially keep topping up the water and tumbling the clothes until it detects that no more water is being absorbed by them.

[@JohnDoe321654]

Did you turn it clockwise and if so, how much? Trying to figure the same thing out myself after seeing endless videos of other people adjusting switches where the set screw is accessible.

[@deniskobozev3916]

This was one of the most enlightening videos for me on your channel. Thanks, Clive!

[@LakeNipissing]

7:39 . . . Little spring: "I'm outta here!!" Genius design with a variable inductor and divider!

[@papinkelman7695]

LakeNipissing I put a capacitor dropper over my tablet speaker and I could hear it gasping for air.

[@ilaril]

I have no technical know-how, nor can I do pretty much any of this stuff, yet here I am, on a Sunday morning enjoying to learn how things work. The only problem I have with these videos of Clive's is that I wish I could actually use a soldering iron and do all the things it would enable. You Sir are fighing neck and neck with Richard Patterson for the "Best Scot in the world"

[@Neffers_UK]

Soldering is piss easy. Just get a cheapy (but safe) soldering iron, some solder, desoldering wick and get some old device with circuitry and desolder stuff. When you have burned stuff out and ripped enough tracks off of a PCB, you'll learn how much heat can be applied and for how long. Soldering components to a PCB will be childs play compared to that - de-soldering can be a proper pain. You literally do what Clive demonstrates when assembling something, heat the pad and the components lead with the tip of the iron, simultaneously add solder and it'll flow, not much solder, just a bit till the pad and the lead are in unison with no gaps. Practice, it's not hard.

[@jusb1066]

yep break some junk before you work on fixing stuff

[@CyberlightFG]

Buy yourself inexpensive kits for practise. Use leaded solder. Don't buy the cheapest iron you can find, take a branded one. Cut copper wire to hand lenght, lay them together in a right angle and solder all joints for practise untill you get a nice mesh with nice looking, shiny soldering joints.

[@simaorodrigues6285]

Get yourself an okay soldering iron (Clive has a couple reviews on cheap ones) and some cheap kit off eBay! You'll be surprised how easy it is to solder through hole components! If you're afraid of messing up, you can just practice on some random dead electronic device you have at home. De-soldering components is a major pain (for me), but you'll get a feel for it. I started off with random things and my first actual kit was the clock kit BigClive made a video on (and then the astable multivibrator), you can "build a long". It's really great when you build something and it actually works. After getting started, you can attempt to troubleshoot and fix random things that break. I must warn you though, when you start being able to fix random things, your wallet will suffer. You'll start wanting to stock some components so you can fix things right away, then a nicer multimeter, then a nicer soldering station... Then you need a little electronics storage cabinet but half of the drawers will be empty, so you buy more components to put in them. Oh and leds, so many leds! Go for it. It's fun, and eBay stuff is cheap!

[@cjmillsnun]

It's ok with the cheapy stations on eBay. Clive uses one himself. Just make sure you have a chisel tip rather than the conical.

[@MrGoatflakes]

I love it when you break things open to release the knowledge inside :)~

[@SvenSchumacher]

"It can be opened without breaking it." "Oh! I broke it!" "This is totally okay." : D

[@MrGoatflakes]

Sometimes you must break it to release the delicious knowledge inside :)

[@RWBHere]

Neat, clever, simple, cheap and reliable. Thanks Clive.

[@SueBobChicVid]

This is why I'm here. Love this stuff! I had no idea something so simple was being done like that. I'd love to see the bit of programming that is being used to convert the pulse frequency to water level.

[@Slicerwizard]

Just count the number of pulses seen over five seconds. Very simple to code.

[@DiarmuidKeaney]

Well done Clive as always, very well explained! Thank you.

[@BenWeigt]

Just finished fixing my washing machine, this was invaluable during diagnostics. Thanks!

[@jp040759]

I would love to talk the guy that came up with this idea and listening to his thought process that lead to coming up with this idea. Impressive and unique use for that chip.

[@stefantrethan]

I expect the man was looking at the ready-made MEMS sensor on his desk he couldn't use for cost reasons and shaking his head. ;-) It's not all fun and games you know. Figuring out that circuit is only a tiny part of the process and by the time you have sat through months of meetings on the more mundane aspects of this sensor you are really looking forward to working on something different.

[@Roflcopter4b]

I have absolutely no idea what almost anything that was said in this video means, nor do I really desire to know what any of it means. And yet I watched the whole thing. Big Clive is really something to behold.

[@mrrhino3412]

It’s so fascinating watching your videos 😂 love your content! ✌🏻

[@limplin7]

Thank you for all your effort and time.

[@electron7373]

Thanks Clive! No high tech CPU sensor here just good old CMOS 4000 logic! The design has elegant simplicity. Cool teardown.

[@mikecowen6507]

The chip was optimized to produce a stable 1Hz output from a cheap 16.384KHz tuning fork crystal. Very interesting use in your application.

[@bigclivedotcom]

Ah! I never spotted that. How useful!

[@therealjammit]

I think the colorburst crystal required was only found in American TV's but found their way into digital watches.

[@mikecowen6507]

Jammit Timmaj This is not an NTSC colorburst crystal. Those run at 3.579545 MHz. The item in question was specifically designed for digital clock circuits. Virtually EVERY electronic clock/watch circuit uses this type crystal. They are practically all the same 16.384 KHz frequency, and in a similar tubular metal package. Look them up! Some colorburst trivia: IBM used a 14.31818 KHz crystal in the original PCs. Why such weird value? Divide by 4 and you get the 3.58 MHz signal for the analog CGA video output, AND divide by 3 to get the famous 4.77 MHz which underclocked the 5 MHz CPU, OR divide by 2 to get the odd 7.15909 MHz which they underclocked the 8 MHz CPU in the PC/XT. IBM got cheap, and reused the clock circuit outputs. That's where the old weird CPU clocks came from. Hardware hackers of the day replaced (soldered) their crystals to be amongst the first overclockers and get their best CPU performance.

[@Graham_Langley]

Watch crystals are 32.768kHz.

[@mikecowen6507]

Graham Langley Yep. Mentioned above.

[@pdrg]

That's really cool - I love good engineering!

[@RODALCO2007]

Very interesting and unusual compared to the normal pressure switch found in many washing machines.

[@andyspoo2]

They're called "Linear Pressure Switches". Must admit, I thought the 'Out' might , have been serial data , but it's way more basic than that! Thanks Clive very interesting.

[@gfairbanks1653]

Oh I am so glad I saw this video. This is exactly the type of housing over the water level swtich on my machine. I hope that plastic screw works exactly like the older models. Thus, turning the screw will allow my machine to fill with more water. I'll soon find out. I'm sick of smelly clothes!!! I'm not going bother prying it open. I'll just use a heated knife and burn/cut a hole on top to access the screw.

[@bigclivedotcom]

The modern machines only make the clothing damp for the first part of the wash to concentrate the detergent and friction between the clothing. If you adjust it, it will probably just compensate for it, as it is monitoring how much water the clothes absorb.

[@gfairbanks1653]

@@bigclivedotcom I'll see. I already exposed the screw. In the older models, turning the screw modified the pressure valve/sensor- so more water was allowed into the drum. These machines are useless, they put a small amount of water- enough to dampen the clothes and then they sit there closed up for 2 hours- smelling like mold.

[@MajsoSVK]

@@gfairbanks1653 Hey! Did you manage to increase water level by adjusting screw or washing machine compensated water level? Thanks!

[@user-di5pc6xq1e]

@@MajsoSVK yes I'd like to know too

[@shizukesajdm]

Great video. helped me with my mechatronics assignment. Thank you!

[@lumpyfishgravy]

Nice one. Cheap, reliable design. The winding should be fairly stable and those caps look like C0G. All they need to do is calibrate the various thresholds. They might even get away without calibration, but if you're going to test it you might as well calibrate it. The low frequency is perfect for stuffing into a capture pin on the main processor, which will be running at several MHz giving plenty of "bits" of resolution. The other beauty of this sort of method is it's a doddle to galvanically isolate should the need arise.

[@andiyladdie3188]

Very good explained, thumbs up!

[@ufohunter3688]

I picked up a few tips and tricks from this clever design. Thanks.

[@abousamah1967]

Thank you Your lessons is very very useful

[@imajeenyus42]

Hi Clive - do you have an EBay link or anything for that transducer? I'd like to muck around with one as well, but the results I'm getting all look like the mechanical variety.

[@davidroberts2920]

Hi Big Clive. How do you test this pressure switch to see if it's working. My washing machine doesn't spin. It will fill and empty but refuses to spin. Checked the motor brushes and they are low but look ok, getting continuity from brush connector to brush connector 4ohms approx. Stripped of the hose going to the pressure switch and was free of debris along with all other pipes. I have heard you shouldn't blow into some pressure switches because it can damage them, I think I have the same one as you (linear). Any help would be most appreciated. Thanks in advance!

[@DextersTechLab]

Interesting, i notice modern washers seem to run the empty pump and pause just before they begin a wash. Could this be to make sure the drum is empty and then perform a calibration/zero on the level gauge?

[@smileypete4625]

True, and same for dishwashers. To get a higher water level for rinsing they allow the water to 'run on' some after the water level switch is closed. However this doesn't work so well if the supply flow is constantly changing due to other large water consumers eg baths and showers, hence the improved sensor. If you take the old 2 level sensors (the second level contact is to protect from overfilling!) apart for 'investigation', they are the very devil to recalibrate properly, just don't ask me how I know this... >:-|

[@Manta_Dennis]

After seeing your video I wanted to do the same with my sensor. Looks nearly identical. However, the LED was constantly on. And I laughed after opening the case. From the outside there are three contacts: S+, GND, S-. But inside there were no electronics. The winding is connected directly to S+ and S-. Only a small capacitor goes from S+ to GND inside. The manufacturers have saved even more costs and moved the IC to the mainboard. 😂

[@PsiQ]

How do they prevent the connector to get clogged up ? There needs to be a small flow of liquid / gas in and out, but it seems as if everything on a washing machine gets clogged up with micro fiber and detergent residues over time... - so why not that small intake for the pressure ?

[@samwhitt9180]

Back at it again

[@johncasor9698]

another great video... thank you so much...

[@proffski]

Excellent school physics project, thank you!

[@HoaLePhuc]

Thank for sharing. I wounder about its chematics. Could you share the detail schematics? Thanks a lot.

[@vladimirrumyantsev7445]

Thanks a lot, this video is what i was looking for👍

[@mrpat2563]

Thanks for that Clive, very interesting, I suppose using this method the manufacturer can control and adjust the water level through software rather then mechanical methods depending on the market it is being shipped to.

[@jurusangizipolkesma6394]

have this with resistor 101 and 103, replaced with other (unknown inside) and not working. how to determine it from outside label?

[@sasacelavi]

Very gratefull explanation...🙂

[@AfaqSaleemChannel]

I failed to get if this one just tells on/off (like full, not full) or it shows the level (10%, 50% etc) inside the washing machine? If its level, I am confused how it reads level with that small travel!!!

[@jeffmassey4860]

Main micro calibrates to sensor at start of cycle? And micro may have a go-no go code if frequency is out of tolerance at start. Hobart LX E undercounter warewashers have up to 3 of these pressure sensors. We can see the values change in real time,in Service mode.

[@jusb1066]

they have moved on, the one i took apart had a 2 level pressure switch, very simple. but that was an old 70s machine with mechanical cam timer

[@toasty4000000]

I watch a lot of your videos on mute so I can work out the mechanisms myself sometimes, thanks to you and Ave I'm pretty good now ;P

[@strangewasya]

Watching this video brought back memories which i didn't want to remember. Oh boy, running all around my city repairing WMs was not a fun job. Clients tried their hardest to skimp on payment(or even forgo it completely), boss was quite loud drug addict who thought that a day not spent yelling at employees is a day lived without purpose. Also he demanded that all of us will be available 24/7. Not fun at all.

[@Neffers_UK]

I'm kinda glad that the new wave of washing machines are taking this approach,as opposed to the really expensive timed device. It means now we have what is essentially simple microprocessor with "simple" software reading simplified sensors. A person with brains could now set about and replace all the gubbins with an arduino and get sensors to make a washer work again, albeit without the "finesse" of the research in washing cycles. YMMV, but still, it's a good thing.

[@bigclivedotcom]

The new machine seems to be doing clever things. It fills up with a small amount of water and then tumbles the clothing for a while. If pauses and sees if the water level dropped and if it has then it adds more water. If the water level did not drop then it knows that the clothing is now fully saturated and that results in more efficient detergent, water and heater use. Then for the rinse cycles it uses a lot more cold water.

[@jusb1066]

yes the old days of 1 or 2 water levels isnt enough, it has to be per load and how absorbent they are for efficiency

[@Neffers_UK]

Yeah I have a horrid Hotpoint washer drier (I never use the drier, slow expensive self condenser)and that does all the fancy self balancing stuff too. It could have been good but it's destroyed the bearings, and fails to saturate clothes properly. I have to put it on a full load for a half load else I end up with tacky clothes. I blame the device you took to bits in this vid, but I dare say that mine is a momentary version, it's really high up, with a really soft silicone hose. And it's running from a timer with a controller, bad combo. I've had it in bits many times replacing rabbit warren split filler hoses and alsorts.

[@Ed.R]

Neffers I was thinking the same, code I'm using to measure rpm from a reed switch would probably work. Arduino controlled washing machine sounds like a nice little challenge. Could get really fancy and have Bluetooth connection to smartphone or maybe thats a little to far.

[@WizardVespian]

Imagine being able to hack your oven to give it PID control for temperature fluctuations using an arduino and say goodbye to +/- 20 degree temperature swings.

[@adrat8339]

How is it calibrated??? That's what the springs are for! Neat!!!

[@wankakiwi]

Hi Clive This looks the same as on an Electrolux washer and trying to adjust the water level. My one has no screw on top. Is there any way to adjust this for more water in tub

[@bigclivedotcom]

Modern washing machines will initially just make the clothing damp initially to maximise detergent strength, increase agitation and reduce foaming. The machine usually adds water, tumbles the clothes and then checks to see if the level has gone down. When it detects the level is the same it will stop adding water. You can't make it add more water during the detergent cycle, it only uses more water during rinses.

[@andycarter5617]

I'm wondering why it is necessary to divide the 214kHz signal at the sensor, would that be because a lower frequency is more able to be transmitted to the controller over low grade wires?

[@bigclivedotcom]

The lower pulse speed gives the processor more time to time the duration and could provide more accurate results.

[@mohsins.3851]

@bigclivedotcom Greetings! I have small question, how do you make a synchronous generator from a induction motor typical found in washing machines. I can provide pics if needed :)

[@mohsins.3851]

I would like to use dc excitation to the coils.

[@772pcs]

"Clever", you`re a clever guy!

[@tehlaser]

My machine “calibrates” by filling the drum until the max level and/or overflow sensor trips when the switch is set to a position labeled “super/reset”. Presumably the brain box stores the reading associated with overflow and chooses some intermediate value for the other settings.

[@Friendroid]

Can the frequency of the output signal be read using an ESP32 module? I have a pump in a rain barrel to water my plants, the sensor could signal the barrel is empty and keep the pump from working.

[@bigclivedotcom]

You can get water level sensing relay modules.

[@ianwright6502]

Clive, what about putting a small dot onto your bench to give you a reference for where the center of shot is. When you zoom in you would be able to tell where you are. Or just keep doing what you're doing. Great video!

[@bigclivedotcom]

I usually do. I may have accidentally burnt it off or something.

[@jorgemef]

I have a washing machine Ariston Aq8L with similar sensor. The output is a square wave of 5V with range that goes from 10,75hz empty to 10,62hz with 2 liters of water. I am wondering if this the appropriate dynamic range as very often the machine fails to drain and starts blinking. This is range with drum stationary as when spinning the drum moves a lot as dampers are worn out and when spinning with normal load jumps between 10,26hz, 10,31hz, 10,36hz and 10,42 hz.

[@bigclivedotcom]

Have you checked the drain pump filter?

[@jorgemef]

@@bigclivedotcom Yes, was first thing I did. I cleaned it but still happening Anyway the machine fills right level of water. The problem is with draining. It keeps draining for long and then it fails. I suspect it is because of the shaking due to worn struts that may affect the sensor readings. But when empty it is a known level 10,75hz. I am wondering what is the problem. I tried a couple times just emptying 2 liters (no shaking) and it seems to work.

[@meelis79]

@@jorgemef did you solve issue? My sensor shows similar Hz readings and I am not sure this is correct - Bigclivedotcom readings were broader range (9-13Hz or so). My machine just runs draining pump and gives F05 error. Like it tries to empty machine and thinks there is still water inside. I cleaned motor filter and even took it off when it tries to drain water

[@apanoiu]

Very nice and useful. How would I trick it to fill with more water?

[@bigclivedotcom]

That decision is made by the control system. These machines initially just make the load damp to maximize detergent strength and friction as the drum rotates. It adds a lot more water for the rinses.

[@Neffers_UK]

A little suggestiong if I may Clive. You say you keep your house cool, so I wonder if it may help to have plastic devices you wish to dismantle near a gentle heat source for a while prior to prying? Or at the very least use your solder station's heat gun to gently warm things up a tad.

[@Lakes57]

Remember that warehouse at the end Of Raiders of the Lost Ark? Well clive has one like that that, but it's all lit by warm white LEDs. :)

[@techalyzer]

If a brit says he keeps his house cool, that's near freezing for the rest of us :) They consider 18C a "heat wave" in the summer LOL. I am currently setting the A/C on 30C to get the room to 24, cause it's cold AF.

[@phils4634]

I seem to remember Clive mentioning that his home was a "toasty" 13C . . . . . Sorry, but our idea of "toasty" is somewhere warmer than 30C! Whilst we regard "hot" as 40C+ - I suspect Clive regards 25C as "quite THE Heatwave!" :-D

[@techalyzer]

That was one of the reasons I'm glad I left the UK (among other ones that will not be discussed here, because I don't want to piss anyone off). Outside, a chilling 13C with wind and rain, and the trains and my workplace were blasting A/C at full power. Don't know about you, but this is beyond ridiculous. Discussing whether it's warm at 28 or 34 is a thing, but blasting AC full-power at 13C is a sick joke.

[@doctorcraptonicus7941]

I see Clive's place more as a Wallace & Grommit type lab, only with more tartan and a robot butler. He pulls a string above his bed which catapults him to his work station & camera.

[@robbieaussievic]

..... I wonder if there is a program calculation detecting load with this, in conjunction with the 'post spin up' g-sensor input (or whatever they use).

[@bigclivedotcom]

The pre-spin balancing seems to use an algorithm to monitor the feedback from the motors tacho. The speed of a balanced load is consistent, but an unbalanced load wavers significantly on each revolution.

[@andygozzo72]

@@bigclivedotcom this is a problem with our machine, its sometimes used just to spin a small but occasionally heavy load, the thing throws a wobbly and just wont spin it, you have to wring it as much as possible by hand before spinning! previous machine was far less of a bitch!

[@TurboTel68]

Analog pressure switch, can remember these appearing about 15 years ago on Zanussi machines

[@millomweb]

So this was the appliance of science then. Just be thankful Zanussi don't make toilet cisterns.

[@mikelemon1147]

Here is a snippet from a service manual of a frigidaire washer/dryer (laundry center) that touches on the water pressure/level sensor. " 9.11 Pressure Sensor - FFLE3911QW and FFLG4033QW 9.11.1 General Characteristics The Pressure Sensor is an analogue device that controls the water level in the tub, used in models with electronic control system, and it is directly connected to the Main Control Board. A tube is connected between the bottom of the Tub and the Pressure sensor. When the tub is filled with water, it creates a pressure inside the hydraulic circuit that causes the membrane to change position. This in turn modifies the position of the core inside the coil, thus changing the inductance and the frequency of the oscillating circuit. The Main Control Board recognizes how much water has been filled into the tub according to the frequency. Operating frequency varies according to the quantity of water in the tub " Specifications Pressure Frequency Diagram ( At Water Level “0” mm (empty tub) Frequency will be 45.4 Hz ) Mm H20* - Hz* : Points with 100% control of frequency output on assembly line Pressure (mm H2O) Nominal frequency (Hz) Water Level at 0* 45.400* Tub empty, 0 pressure and frequency is 45.4 Hz 150* 43.140* 200* 42.350* 350* 39.990* 500* 37.772* 600 36.560 Tub if full and frequency 36.560. Mm H20* - Hz* : Points with 100% control of frequency output on assembly line

[@ReneSchickbauer]

Theoretically, yes, the CPU could do a "count the pulse length" and directly control the valve. But that could lead to a flooded room in case of a software bug or (only slightly less bad) a completely overfilled drum which would damage the bearings and possibly overheat the motor. You could do a rising edge-triggered monoflop and something like a couple of xor/and gates - so if the monoflop still outputs a signal when the transducer doesn't, it enables a second monoflop (or capacitor) for a couple of seconds, which in turn enables enables a transistor between the CPU output pin and the water inflow valve. This way, you make sure that the CPU requests more water AND the water level is low enough.

[@dariovicenzo8139]

Why this guy eliminated the very good switch for anti-flooding that there was inside the previous pressure switch? No complicated software, no hardware required, only on-off switchs. One for the first level, one for the anti-flooding. Only a 110/230 VAC sensing on one microcontrollor pin.

[@gavincurtis]

Surprised it isn't an ARM cortex A5 running embedded windows or some other over-engineered bullshit sending 512 bit encrypted one-wire serial data packets to the host controller board in the washing machine for water level.

[@cardboardboxification]

The Dollar Guy then it wouldn't work,

[@tin2001]

Who runs Windows on ARM? What a waste of money :p

[@tin2001]

Would have been funny if it had an Atmel chip and some dodgy Arduino sketch.

[@Razor2048]

Windows CE is pretty reliable, assuming you configure it properly. If using it for a single task device (e.g., those random price scanners or other basic things), you need to disable as many other services as possible, especially if using the units with 32-64MB of RAM.

[@gavincurtis]

tin2001. Exactly along my line of thinking.... :) Three layers of virtual machine shovelware stacked on each other by a lazy programmer so it takes 23,679 clock cycles to execute one CPU instruction with a disabled watch dog timer.

[@garywilson-2e0apg93]

Just out of curiosity could it be used in conjunction with an arduino to monitor a fish tank water level?

[@bigclivedotcom]

Yes it could, but a float switch would also be a simple solution.

[@leebromley1411]

Would the output of the Oscillator (8-12) be directly related to how much water in litres is in the machine?

[@Slicerwizard]

The output is directly related to the height of the water column pressing on the diaphragm.

[@leebromley1411]

I realise pressure is applied to the diaphragm from the water in the in drainage sump. However in my Samsung machine there is a similar device which sits in the sump at the bottom of the drum next to the drainage hose which leads to the pump. As our Samsung is a EcoBubble machine there is very little water in the machine. I think the last time I had to manually drain it due to a blockage in the pump I only counted about 7 litres of water. Which leads me to think this device is calibrated directly in relation to the actual amount of water in the machine rather than just any old number being generated.

[@brucewilliams6292]

Also, what is the part number? I need something like this for several projects.

[@bigclivedotcom]

Search for Indesit water pressure on eBay.

[@Steve3dot1416]

About the same look, the DC96-01703G only have the two pF capacitors on the PCB, nothing else. There is a 23ohm resistance between the two signal pins or the module and it does not vary when I move the ferite log. Possibly the reason why my washer does not detect water level and produce an OE code. I suppose the role of the IC as been moved in the main controller board.

[@dariovicenzo8139]

What you suppose it's corret about the chip.

[@ronaldrissel6665]

Yes, I also took a DC96-01703G apart, and can confirm that there are just 2 capacitors on the board; no IC. And yes, moving the core of the coil in or out will NOT change the resistance; but it WILL affect the inductance of the coil, and the resonance of the tuned circuit.

[@charesealbow5357]

Hi Clive. Do you atill rmemeber qhat make washing machine was this sensor for? Plan to get one of this sensor to experiment with

[@bigclivedotcom]

It's common between brands like Indesit and Hotpoint.

[@robertomartin8731]

On my washing machine that thing got out of alignment. Its hard to return to factory specs :/

[@lesliedaisley7846]

So how do you test these type of two pin pressure switch to know if they are defective

[@bigclivedotcom]

It's not easy to test this type without making up a dedicated tester. It will be easier to just buy a replacement and install it. If your machine seems to be using very little water in the main wash cycle then it's normal. It only uses a lot during the rinses. Initially it just aims to get the clothing soaked in a minimal quantity of water to increase the detergent concentration and give better friction when tumbling.

[@carolinemills1282]

I've just done the PCB motor controller replacement with solder and everything (help from mickr1969). I was amazed when I put int spin and it worked....but my joy didn't last. It would now spin but wouldn't fill. I managed to get it to fill by blowing into the sensor. (yes I know I shouldn't). So I concluded the sensor was faulty. Just replaced it and .....it doesn't work. Eventually it comes up with a 4C fault which I don't think is correct as it will work if I blow into the sensor. I am now guessing that it is something to do with the level calibration at the start? Any ideas? I can experiment as I now have two sensors : ) It's either me or the machine!!

[@AiOinc1]

Hey we use these on our dishwashers Hobart LXe, AM16, CLeR, FT1000E (with dual rinse) That said, ours are true analog. The output is generally 400-2000mV

[@markkupartanen9583]

@bigclivedotcom can you pleasd take apart new dishwasher sensor. I change one on my samsung. It had weird leds and angled sensors. I have absolutely no idea how it can measure swirl or dirt in water.

[@andrewwhite1793]

Markku Partanen Hi, reflecting light of a water surface can measure distance to the water (level) and also the speed of flow with some maths in the microcontroller.

[@bigclivedotcom]

It looks like a very standard component available for experimentation on eBay. (Not necessarily compatible with your machine). The main function seems to be to detect cloudiness of the water optically. www.ebay.com/sch/i.html?_from=R40&_sacat=0&LH_BIN=1&_nkw=turbidity+sensor+module&_sop=15

[@ohboy7790]

could one of these being faulty trip a circuit breaker? ive checked the heating element by disconnecting it, the water drains out of the machine when it starts up,, so not the pump, the water runs into the prewash section of the detergent tray and then once the water for the main section of the wash starts the breaker trips!! ive replaced the water inlet valve and it still trips at this point so not the solenoid in the water inlet valve, next down the line is this bad boy and mine looks just like this one. washer is a bush A127QW. thanks!

[@bigclivedotcom]

It's unlikely to cause rogure tripping. Two common reasons are the heating element and sometimes the incoming supply electrical filter.

[@ohboy7790]

@@bigclivedotcom thanks for the reply. ive disconnected the heating element so its not that and ill look at he eclectic filter, i dont know what it is yet but ill check that out thank you. but why would the machine start, run through the prewash section of the cycle then cut out every time right when the solenoid switches to the main wash water inlet, some water comes through but it switches off/trips the breaker within 1 second.

[@ohboy7790]

@@bigclivedotcom incoming supply electrical filter roger that, ill try that tomorrow! youre a top G big clive!

[@ohboy7790]

@@bigclivedotcom ok so heres an update, ive swapped out the mains interference electrical filter and things have improved but now its doing something else. the machine now makes it past the prewash and fills the drum with water for the main wash, then it stops seemingly ready to wash the clothes, and then the stop cycle light flashes a bit then the machine drains the water, stopping the cycle :(. man im so close, what do you think?? is this now a motherboard issue? thank you!

[@johnpossum556]

Very interesting little design! Dynamic variable inductance. One IC that one would not have designed like that before the HC version came out. In fact why do they even need the HC version and not just the C version? HC is High speed Cmos and it's really not going all that fast.

[@superdau]

C versions? You mean HCT or LS, or not? You don't pick a certain type for speed in a setup like this. You pick it for the logic level voltages and/or whatever logic family can drive the "weird" inductive oscillator.

[@bigclivedotcom]

It might be the easiest to source. I was pondering why they didn't use the CD4060 base CMOS version. Maybe this version has more robust outputs.

[@johnpossum556]

Right. Could be the rest of the washer is TTL and they want to stick with these "standardized" TTL voltages unlike the cd4060. I've taken apart my share of washing machines and never seen anything this complex used. Last washer I took apart had an extra side tank with a little float that lifted a plunger that turned off the water level off. That was it. No oscillator, no frills. ( I put the motors to good use as buffing/grinding wheels and another as a Wolverine rip-off sharpener for my wood lathe tools. They're super for that & run very quietly.)

[@jaycee1980]

The HCMOS version is probably the cheapest version in quantity at this point.

[@Lumibear.]

Does it really need to be that complicated? I mean, I guess so, as it works, but I feel like this is a bit overkill. I wonder if you could use the moving parts as a surface vibration speaker?

[@maxtorque2277]

complicated? Sure, the IC is complex, but that is made, in it's millions under very controlled conditions. That means the rest of the device is actually very simple, with just a couple of moving parts, and only one "wearing" part (the diaphragm itself), unlike the old mechanical pressure switches that were levers, pivots, springs, and on which the contacts wore everytime it operated

[@Lumibear.]

Max Torque Well, true, less electrical contact areas to wear out, for sure.

[@rayner1guerra]

Can I replace this W10448876 pension switch of a Whirlpool duet and put another mechanic pression switch. Other technicians are doing that , the board of the washer let other connections. Can you investigate, my boar have empty slots.

[@bigclivedotcom]

I'd recommend only using the correct type of sensor.

[@woofer2121]

would it have been simpler to just use the resistance of the coil as a level indicator?

[@simonruszczak5563]

It is using a coil's resistance, which is inductive resistance, the resistance to AC flow.

[@maxhammick948]

The range of 0-0.3m of water quoted on the casing corresponds to about half a psi, which is well within the typical range that people can produce from their lungs. Might be interesting to blow in it if you ever run into another?

[@jaycee1980]

That's a good way to test the old pressostats :) Should work with this as well

[@JorgenHenningsen]

Is it possible to measure the value of the capacitors in the oscillator?

[@bigclivedotcom]

I just isolated the caps by cutting tracks next to them. They measured 2.2nF (2200pF).

[@phonotical]

Is that a digital or optical zoom on the ipad? Never really seen the kind of loss of detail associated with digital zoom

[@jusb1066]

digital zoom, its not as bad now to use a bit of digital as the sensor has plenty of spare pixels to zoom with

[@bigclivedotcom]

Digital zoom but just homing in on a smaller area of a large image array. It's a Moto G4.

[@phonotical]

bigclivedotcom it's a fair bit better than it used to be, think I'm strictly an optics guy

[@piecetoyou8285]

Is there away to test this type of pressure switch with multi meter without taking apart

[@bigclivedotcom]

Not easily, since it doesn't have a simple switch. It's often easier just to put in a replacement to see if it fixes the problem.

[@ImnotgoingSideways]

3:26 How it calibrates: Two opposing springs of equal strength and a cross head threaded insert bonded with anti-tamper marks. Allows for dialing in the 0 position at factory. =^-^=

[@misterhat5823]

That's probably not a Schmidt trigger gate. That would be used for an RC oscillator. For an LC or crystal oscillator, it would be a standard gate forced into its linear region and acting as an amplifier.

[@lauramorris6407]

could you have a look at what is inside one of those yellow transformer boxes found on building sites ect

[@jusb1066]

a transformer, nothing else, no other bits, sitting in oil in a sealed plastic case, it only drops 240 to 110 ac, very simple to do

[@bigclivedotcom]

It't literally just a transformer and sometimes some fuses too. Usually potted into the case with the terminals and fuses protruding through the potting compound.

[@r-urbex1611]

Arnt the newer ones digital?

[@jaycee1980]

How exactly would a transformer be "digital" ?

[@jaycee1980]

Ugh, they do inverter based ones? Completely missing the point of a site transformer in the process i'll bet... :/

[@AbdulAminGani]

Haven't watched the full video yet, I'm guessing it's a strain gauge?

[@bigclivedotcom]

+AbdulAminGani Good guess, but it's a lot cheaper than that.

[@Graham_Langley]

That 200R resistor should be on the output of the gate, not the input. Edit: And looking at the PCB the coil appears to be connected directly to pin 11, which is the input to the first gate in the oscillator cct.

[@Kacavida11]

I just came across one today, now i know how to test them, if I didnt brake it in the first plave (i shorted +5V and Out, Grnd was never touched nor shorted)

[@VinayakaAbase]

Hi, please do a teardown on non-contact liquid level sensors. XKC-Y25 etc.

[@bigclivedotcom]

They look like capacitive sensors.

[@xxrs2009]

Nice vid. funnily enough this is called an analog water level sensor or pressostat. The old one which has 2 modes: On / off is a digital pressostat, because on=1/ off=0. It also clicks when you suck on it.

[@gaetanobruno2774]

my washing machine empties all the water every time I change the program. How can I trick the pressure switch into believing for a few moments before starting the new program that there is no water?

[@bigclivedotcom]

It's usually in the software that the machine will want to start from an empty drum so it knows the state of the water in it.

[@jtveg]

Love your video teardowns. 😉👍

[@jtveg]

Против Глобал Indeed. ✔️. 😉👍

[@zx8401ztv]

The word "sneaky" came to mind for that L/C oscillator to divider :-D

[@bigclivedotcom]

Very sneaky. Never seen that arrangement before.

[@techalyzer]

I guess mine is blown or something? The machine began to just stop, and I know it's an electronic issue, cause it mechanically runs perfectly fine. It just randomly stops, and when it does, it's a PITA to get it back moving. Yesterday it filled up almost to the top and then began full-speed dry-spinning without spitting the water out first. That was a delight to watch, got myself a little fountain here :)

[@bigclivedotcom]

That could be the water sensor not being detected or failed. If used in other modes does the motor run? Another possibility is very worn brushes causing intermittent operation and possibly glitching the processor too.

[@techalyzer]

Out of the question, it runs perfectly, sometimes a full cycle. I figure it must be the small tube going to the sensor or a bad connection or something, I have to open it up. That's the thing, it's not even close to being dead yet, it just randomly stops working once in a while. I already took out the PCB, washed it (it was full of dust) and resoldered all the connections, as some appeared to be bad, but it didn't change much.

[@Graham_Langley]

The hose(s) from the bottom of the tub to the switch(es) often get blocked.

[@therealjammit]

As an added benefit the CPU can self zero the sensor. When you first start a load the CPU knows the drum is empty. It then samples the sensor and uses the reading to use as a reference for zero. Short term accuracy would be close enough and you don't really need long term accuracy (plus you can self zero again after the dirty, sudsy water is removed and right before it fills again for the first and optional second rinse).

[@JL-it9wo]

Can you adjust it so the machine will fill more?

[@bigclivedotcom]

No. The machines only look for a change in water height to see if the clothing is still soaking up water. The point is to only make the clothing wet initially so that the detergent is at its most concentrated, and so that the clothes rub together as they are tumbled instead of floating in the water. It results in a much better cleaning action. After the detergent cycle the machine will use a lot more water during rinsing.

[@JL-it9wo]

Ok. Many people are modifying the front load washers, so they use more water.

[@jasonhamilton5756]

I've done some work for appliance manufactures and their method is the K.I.S.S. method you'll find in nearly every shop in the world. Simple keeps cost low, complexity low and in effect failure rates low. Using this configuration probably lets them use the same sensor in a sophisticated IoT machine with fully integrated feedback on the HMI and let's them use it in the "old fashioned" simplified models as well. Oddly enough, if you can salvage these sensors they work great for years and cost a fraction of what an industrial robust equivalent would cost. They just have a lot less documentation available to work with which makes integration much more difficult, unless you take one to bits and make a schematic. Ofcourse, that said it does explain why replacement sensors are so expensive to buy new. Robust industrial sensors are very expensive to buy, and they wouldn't want to flood the market putting themselves out of business or putting precision sensor makers out of business with simple cheap devices. There are huge differences in application for both. Thanks for the video Clive.

[@dariovicenzo8139]

Hi Jason, do you know somethings about this sensor? Like I have to read the frequency by a micro?

[@jasonhamilton5756]

@@dariovicenzo8139 I know a little about a lot of things. If you want good understanding of sensors, how they work, and what they actually detect I suggest reading Grob and Malvino when you are ready for solid state. They cover the base physics and cover the base chemistry of how devices function and are good first year books for any EET or hobbyist.

[@denismckenzie1991]

There's an awesome product called the Olegtron 4060 MK2 experimental synth, and they are using the CMOS 4060. They basically break the chip out into a bread board so you can experiment with patching the divider (counter) and osc sections. Absolutely my favorite audio toy, and I think you would enjoy it as much as I do. I've taken it apart (obviously) but there's a lot I'm not sure about. If you are interested in checking and maybe doing a video 😉 Here is a link to their site. www.olegtron.com/olegtron-4060

[@denismckenzie1991]

P.s I want to be clear that I'm not affiliated with Olegtron in anyway. I realized that my last comment might have come off sales-ey. I swear I only have good intentions. 😀

[@kagami8779]

"Oh, I've already broken this." That just might be the quickest yet.

[@bdot02]

At 1:06 it looks like you had a good at opening it before you hit record :p

[@bigclivedotcom]

+bdot02 I did, and when it started cracking I decided to record it before I broke it completely.

[@jhonsiders6077]

The one on my washer did not let in enough water to fill it tightening that screw it will fill higher It did not have a chip in it just a set of contacts .

[@jaycee1980]

That's an older style "pressostat switch"

[@gerryscully9248]

How do you test this?

[@ronaldrissel6665]

Yes, I also wanted to know how to test it in the field. Now that I know how it works, I think you might be able to use a multimeter with a frequency function, or use a graphing multi-meter (which I have) and find which terminals (signal + ground) that have a "frequency" on them. First verify that you have approximately 5 VDC going into the device. Now you've identified ground and the Vcc lines. Then, connect your meter to the 3rd terminal and Look for a frequency of around 8 to 16 Hz. Then if you carry around a small piece of tubing with you, you might be able to attach it to the sensor, blow into it gently, and see if the frequency changes. (I have not tried this method yet, since I just saw this video, but I will try it the next time I work on a Samsung washer.)