#161

[@williamna5800]

As someone who watched many YT Videos, mostly scrounging around for electronics info I am always glad to see a video addressing the topic I am looking for/interested in even if not really a "well done" video. Then came the day I stumbled on your channel and I have found myself watching other videos thinking "if Andreas had done this video I would already have my answer and a working example AND all relevant info explained in a video that isn't 45 minutes long and putting me to sleep" As always, clear and to the point as a YT video should be. Well done.

[@AndreasSpiess]

Thank you! During these videos, I usually think: "If I Had More Time, I Would Have Written a Shorter Letter" (A quote attributed to several authors)

[@bmoroneyau]

Thank you for your projects and for your insight into electronics. You've inspired me to not only connect and program the ESP32 successfully (just finishing my WiFi weather station) but with this latest project our cat may never go hungry again! Thanks again Andreas for producing these videos and helping inspire a new community of makers!

[@AndreasSpiess]

Thank you for your nice words. Enjoy your ESP32!

[@Chuenthe]

Wow, this is exactly what I was looking for! I have been migrating a project to the ESP32 (using the DS18B20 temperature sensor) and it kept dropping values where the previous Arduino did not. So it's just too fast! Can't wait to try slowing down tomorrow. Also, I am a hobby beekeeper and wanted to experiment with logging the weight of my hives over the coming season (I'm in New Zealand the season is just starting). So I've got my next project lined up already! Thank you as always for the great video!

[@AndreasSpiess]

I also plan to become a beekeeper when I have more time. Seems to be interesting and important these days.

[@deangreenhough3479]

I would love to see progress on this, as Andreas points out, it is becoming even more relevant.

[@charlesdorval394]

Jens Stein: There's a bit for "conversion in progress", you might want to check that bit to make sure the conversion is finish when you're reading. IIRC on one of those model of DS temp sensor, you can also select the precision to get faster reading if you don't need 10bits. Hope this helps! DW

[@Chuenthe]

Hi Charles, that was very helpful, thank you. I was able to solve the issue by just setting the resolution to 9 bit (from default 12).

[@PatrizioBekerle]

I will test if slowing down also solves my problem with reading from a DHT22 temperature sensor...

[@richard_wenner]

Spiess's Law 'The cost of any ADC should not exceed the cost of what it's used to measure'. I have never considered that, in the past, but now you have enunciated it - it's so obviously a fundamental law of the universe! A small gravitational wave of shock has just been released from Wales - as a consequence (did you see it on your strain gauge?.

[@deangreenhough3479]

Richard Wenner Ohh Richard, well said😀

[@coreddit]

Sometimes you need to measure stuff with negative value. Like garbage. You need to pay to get ride of it. What ADC would you use?

[@deangreenhough3479]

cored 😂 a rubbish one maybe. I like your way of thinking 👍

[@3zuli]

But that would mean we can't use our expensive oscilloscopes to measure our cheap Arduino circuits... 🤔

[@AndreasSpiess]

+3zuli: If there is a rule the exception is not far (other law)...

[@jasonmhite]

Great video as always. I've had a project idea to make an automatic cat feeder but kept putting it aside as I would came up with problems, one of which was how to tell how much was in the bowl. Maybe now I should go back and revisit it...

[@AndreasSpiess]

Adding an automatic feeder is a good idea! Maybe for another video...

[@Emillos82]

Great, and again super timing! I have a litter box alarm for our cat mishka ;) based on the door pulse. Friday a collegae suggested to measure it and I was already looking for a scale with serial connection. But of course now Mr Spiess comes along and gave a much better inspiration. Thanks!

[@AndreasSpiess]

Glad to read that. This should be possible. Maybe you use square gauges like the one I showed. They are used for body scales and can be placed on all four sides of a box. Would probably be more stable.

[@richard_wenner]

It's stunning how sensitive these gauges can be. Your, Dishka, cat pellet demo is an example of this but given the leverage effect of the bar, surely the pellet will record a different mass depending upon where in the dish it is placed. My bar, which can tolerate up to 20kgs, can currently differentiate between one and two match sticks!

[@AndreasSpiess]

Indeed unbelievable! I never went this far. This is a very big range!

[@deangreenhough3479]

Good Morning Andreas 😀 Yet another example of something I had no apparent interest in - strain gauges. Well, I'm sitting up and all of a sudden interested! Both my missus and my cat 🐱 have also been watching this video and I have been given a few looks suggesting it's time to build one😀 A great tutorial, I especially liked the esp32 and the issues along with your tips and tricks. You say the ADC should not cost more than the cat😂😂😂😂 Andreas you are quiet the comedian. ✌️ Keep up the hard work my friend

[@AndreasSpiess]

As always, thank you for your nice words. They are always part of my Sunday morning. And they motivate me to start searching for the topic of next week's video...

[@nburton01]

I've had all the parts for this project for some time and remember seeng your video. Worked a dream and like you I’am amazed at it’s accuracy. Would have never thought of slowing down the esp32, great tip. Saved me many hours of debugging. Just got to get a cat now :)

[@AndreasSpiess]

This is why we all love KZbin ;-)

[@vivetgrosalexis1413]

hello, it's always a pleasure to watch your videos. they are carried out with so much pedagogy that you manage to explain the most complicated things simply. Well done. Alexis. France

[@AndreasSpiess]

Thank you for your nice words!

[@GeekMustHave]

Thank you for showing a unique combination of technologies for solving the "Is the cat's bowl empty?" I often wondered what Node-Red could be used for now, I have a good example. You do such a good job explaining the technology bits and bobs that it makes the big picture much easier to visualize. That is a rare talent. Leep broadcasting.

[@AndreasSpiess]

Thank you for your nice words. In fact, I used this cat feeder only as an example to show the concept. Our cat does not really need more food...

[@SamFugarino]

You got me with the cat. Thanks.

[@AndreasSpiess]

That is what I hoped ;-)

[@mikecauser]

"As with all models" :-)

[@LatinDanceVideos]

That was really cool. Special thanks for resolving the slowdown to eliminate anomolies.

[@AndreasSpiess]

:-)

[@alidollar1994]

10:36 "as with all models she had to starve a little before her appearance" that was hilarious :D btw great video as always!

[@AndreasSpiess]

Thak you for your nice feedback!

[@Raptorman0909]

Yes, and now cats are taking over electronics videos -- is there nothing they don't dominate?

[@MaxintRD]

Great video again. Thank you for your clear explanation. I hope your cat was paid well for starring in this video! Perhaps you could also weigh the cat and give it some automated laser guided exercise when overweight?

[@AndreasSpiess]

She loves to play with the straw. But only for a few minutes. Then she is "tired" and sleeps the rest of the day. I am not sure the laser would change that ;-)

[@ziliboba73]

Andreas, thank You for your videos - always very interesting and helpful!

[@AndreasSpiess]

You are welcome!

[@henrikworg350]

Sunday Morning 6 o clock 😃👍🏼 at the Point ... accurate like a Swiss clock 😉

[@AndreasSpiess]

Früher Vogel fängt den Wurm? Oder gerade aus dem Ausgang gekommen :-)

[@henrikworg350]

Andreas Spiess 😂😂😂👍🏼

[@birnodin]

In the last 5 years I have seen many KZbin videos. And while I am watching, I eat chocolate, ice cream, potato chips etc. I need a weight control for me that reminds me with a 100db alarm to stop eating...

[@AndreasSpiess]

Good idea! But I am not sure the sound would be enough. Maybe you need a harder punishment, or a big award if you do not eat ;-)

[@lioman2578]

great! Next level is servo motor filling the Dishka's bowl. Thank you.

[@AndreasSpiess]

Maybe :-)

[@TheM4rten]

absolute nice video as allways on your channel ! keep up with that high quallity videos ! thumbs up

[@AndreasSpiess]

Thanks!

[@ZsomborZsombibi]

What a good subject chosen as example. Measuring also cats' weight and matching them with RFID reader, you get a long term, fully automated cat-growth monitor :)

[@AndreasSpiess]

Good idea!

[@4.0.4]

I like the historic pictures! It's good to give some honor to those who invented and discovered what we use today.

[@AndreasSpiess]

Thanks for the feedback.

[@felineseele]

Sehr schönes Video, und die Katze sieht unserem Kooper verblüffend ähnlich, Farbe, Umfang und Strubbelfell stimmen genau überein ...! Beim Abnehmen hilft auch, Katzen auf (fleischreiches/getreidefreies) Nassfutter umzustellen, da es nicht erst im Magen aufquillt und dadurch schneller sättigt. Like geklickt.

[@AndreasSpiess]

Wir haben auf Anraten der Tierärztin auf Trockenfutter umgestellt. Ist auch für uns angenehmer. Wir schauen schon, dass sie nicht zu dick wird, sonst muss ich was hören, wenn "Tante Doktor" das nächste Mal vorbei kommt ;-)

[@ferijusko8775]

Hallo Andreas, deine Videos sind Klasse.... Danke! Feri (Thurgau)

[@AndreasSpiess]

Gern geschehen!

[@klassichd10]

Thanks for the great Video. I like gages and such stuff. This kind of project is perfectly to use the "oldfashioned" ESP8266 out which are not as fast as the ESP32.

[@AndreasSpiess]

I only used the ESP32 to test some of the libraries. I think we should get an overview on which libraries work and which not yet.

[@klassichd10]

Yes, for several weeks it gets better and better. Nearly all what I tested worked. And of Course, ESP32 is more attractive buzzword nowadays. Usually I see beehives in goups, so a multi tasking mode would be needed. Or a a dedicated Controller per beehive measuring additional Things like temp + humidity, Irradiation or whatever maybe useful for a beekeeper.

[@rkaid577]

Cool project and good explanation! Although, when i had a cat he never failed to notify me if he was hungry and his bowl was empty... lol - but of course he couldn't tweet. Idea: Make an automatic feeder that triggers when bowl is empty and a certain amount of time has passed since it reached zero. And maybe only activate that function if the cat has to stay at home alone for a long period of time. For example: It should be possible to trigger it only if your (and your wife's) phone isn't connected to your local wifi (thus assuming that no one is home).

[@AndreasSpiess]

I think your idea about a feeder is a good one. Thanks!

[@AllanKobelansky]

In your video you mentioned temperature compensation requirements. A Wheatstone bridge takes care of that. Nice job.

[@AndreasSpiess]

You are right.

[@elson2k]

Nice and clear, as usual. Great video! This will be my next project (my cats also saw the video and they convinced me to do it).

[@AndreasSpiess]

So, good luck! You should now find the links for the products, too

[@elson2k]

Sweet, thanks ;)

[@albertroswell]

new viewer, especting to play soon with my ESP, thanks for the videos, you are awesome

[@AndreasSpiess]

Welcome to the channel!

[@swissdani71]

Elektonik und Kätzli, fantastisch! 😍

[@AndreasSpiess]

Danke!

[@noelwalterso2]

Thumbs-up for your cat being the spitting image of my old cat Stanley (RIP)

[@AndreasSpiess]

Hope he was also such a nice animal.

[@HRTLmusic]

thank youuuu!!! you fixed my project up with the esp being too fast for the HX711!! i was pulling my hair here haha)) thanks!!!

[@AndreasSpiess]

You are welcome!

[@norberthartmann5075]

ups - YT hat den text gelöscht ... Super !!! 100Punkt das ist genau passend für mein Winterprojekt... die Bienen-Beuten-Waage :-) ggf gibt es ja mal ein update mit 4 Sensoren und dem schreiben von Daten in den Speicher des ESP32 ( habe dazu noch nicht ins prg geschaut ob es schon gemacht wird ) die Wiegeroutine , vor allem das eichen, des prog wird mein Sonntag Nachmittag Projekt und dann wird aus der katzenfutter-Waage eine Kaffeetassenwaage ;-) .... danke und Streicheleinheiten an die kleine Dame ! ps.: deine Filmchen zum Sonntag sind immer wieder toll !! -

[@AndreasSpiess]

Danke für deine netten Worte. Nein, die Werte werden nicht abgelegt. War für dieses Szenario nicht nötig. Das Eichen hingegen findest du (als Kommentar). P.S. Du bist schon der zweite Bienenzüchter in diesen Kommentaren!

[@norberthartmann5075]

:-) das thema ist bei den bienenfreunden auch ein grosse Thema.. als wiegen über eine zelle oder wiegen über vier zellen ( was ich von der hardwareseite besser finde....) doch beim eichen des sensors scheitere ich immer wieder - irgendwie finde ich da nicht so wirklich einen recht genauen weg... ok beim wiegen im Bereich von sagen wir 50-150 KG mag das nicht wirklich das Thema sein doch auf 1-2 kg solle es passen ( so meinen einige ansätze das man so das ausfliegen eines Schwarmes auch erkennen kann .... das sind so 1-2 kg bienen :-) ) ja, die Daten des wiegesensors "grinsen" da auch schon ein wenig.egal ob China oder bosch wiegezelle H30A, diese zelle ist eigenlich in 90% aller käuflichen lösungen ..... und wenn die mal nette kleine reflexlichtschranken unterkommen und du kein Thema findest: zählen von Impulsen aus zwei Richtungen ;-) - also das zählen der bienen im Volk über die Fluglöcher ( klar dann in einer speziellen Bauform - dann ist das einzelne Flugloch nur so breit wie eine biene ) :-):-) ach: und irgendwann steht dann der datenaustausch über "deinen" datenweg an .... du siehst auch bei den bienen ist die Elektronik angekommen :-) :-) in diesem sinne!

[@manickn6819]

Sir excellent video. Since my last comment some time ago I started up loading videos. There are about four presenters that influenced that decision, yourself being one. The aim is largely to document the hobby stuff I do and structure it but hopefully it helps someone tinkering. One video I did that is relevant to this video is a kitchen scale I opened recently to repair. Just a broken contact so that was simple but then I started wondering if it was feasible to fabricate one. I pulled up parts on ebay and it appeared to me that it was indeed economical. I did not consider the voltages and the need for the HX711. This video has been most informative on a topic I did consider though not order parts or build. If you care to have a look and comment I can post a link. Critique is good. I need to improve my level.

[@AndreasSpiess]

I answered in one of your videos

[@manickn6819]

Thanks. The video I was referring to is the one with the electronic scale which is similar to this. The same problem will occur though with my volume level and accent making it difficult to understand.

[@PatrizioBekerle]

Setting the cpu clock manually to 160 or 240MHz also solved my problems with reading from a DHT22 temperature sensor... Thank you very much, Andreas!

[@AndreasSpiess]

You are welcome!

[@middelbh]

Andreas Spiess see my problem I described on using hx711 and ds18b20 on an ESP32; 80mhz is OK for the hx711, 240 mhz works for the ds18b20.....

[@madrian_hello]

What a beautiful cat!!! 🐈

[@AndreasSpiess]

I will tell her ;-)

[@BEdmonson85]

Haha, this was fantastic! What I would like to know is how on Earth you got that cat to not rip your project apart!? My cat goes in to crazy mode when he sees wires just flapping around like that. He would have forgotten completely about the food and ripped those wires to shreds! lol

[@AndreasSpiess]

She is already old. So, eating is more important to her...

[@nicklaspersson4687]

Great video again. Strain guages can be used in a lot of mechanical applications and are rarely found in electronics videos. A more relevant problem for me is that my too hunter/lovebuggs often bring in prey/ 'presents' thru the catflapp in the door. I have been thinking about an image recognition system that could only open the flap if the cat is NOT carrying something in its mouth. This is a bit beyond my skills programming skills, i think the software or parts of it is already 'out there' for this. I think the cost of the hardware is not a problem basically I'm thinking a rasberry PI, a camera and a gpio pin on it to control a relay that controls a motor to open the flapp. My cat has a rfid chip in the neck but the problem I would like to solve is to deny entry if something is not 'normal' under the nose.

[@MaxintRD]

Nicklas Persson - You could detect if the cat is carrying prey by measuring its weight on both exit and entry. If the cat got heavier, is must have gained weight somehow, or - more likely - carry some prey... Just a though: Instead of bluntly refusing entry, you could perhaps train the cat to dispose it in a reward bowl that exchanges the prey for some cat candy...

[@nicklaspersson4687]

I am all for simple solutions but a cat pees and poops outside and the weight of this greatly varies and would sometimes exceed 10-15 grams of a small mouse, bird and sometimes not. I am pretty sure my cat or any cat can not be trained to do leave its pray where I desire and most cat owners would probably agree i'm sure. I do appreciate the effort.

[@AndreasSpiess]

+Nicklas: Fortunately, our cat does not catch any animals and we even do not have a cat door. So, she has to wait till we let her in. But most of the time, she is anyway inside. + Maxint R&D: Good idea with the weight. If the animal in the mouth is not too small... Concerning exchanging it with a candy: I am not sure if a dead animal is already a candy for a cat ;-)

You can do that using OpenCV and Tensorflow. Some examples: medium.com/towards-data-science/building-a-real-time-object-recognition-app-with-tensorflow-and-opencv-b7a2b4ebdc32 www.pyimagesearch.com/2017/09/18/real-time-object-detection-with-deep-learning-and-opencv/

[@nicklaspersson4687]

Thanks Lucio for thees links. This was what I was thinking of, hoping someone already has done this with a cat. Measuring the weight of the cat will not work unless the cat that always and without exception pees and poops indoors. Most cats prefer to do their 'business' outdoors with irregular intervalls. The cat may also have a drink or eat a prey or stolen food from neighbors cat or dogbowl while outdoors that will add to its weight and that should not stop it at the flap. I want to only stop cat from carrying prey indoors. This example shows how important it is to understand the context that an automation device is applied to.

Congratulations Andreas! Thanks for sharing!

[@AndreasSpiess]

You are welcome!

[@Barbara-yl4rf]

Thank you! You save my project!Great Video!

[@AndreasSpiess]

Glad it helped!

[@hvanmegen]

I love his video openings.. and I also refer to him as 'the guy with the swiss accent' and all my youtube watching friends instantly know who I mean :P

[@AndreasSpiess]

That is what the call "branding" ;-) Thanks!

[@madrian_hello]

Very genuine projects.

[@AndreasSpiess]

Thanks!

[@hesspet]

Unsere Katze hat sofort ein Build bestellt. (Die ist auch langhaarig....) Danke für diese nette Idee...

[@AndreasSpiess]

War eigentlich nur als "Demonstrator" für das Thema gedacht. Unsere Katze braucht nähmlich eher das Gegenteil von mehr Futter...

[@hesspet]

:-) Meinung meiner Frau: sowas brauche wir nicht, die mauzt so laut rum, wenn der Topf leer ist, das schafft kein Smartphone.. :-)

[@AndreasSpiess]

:-))

[@harrilumme1875]

Hello Andreas and thanks for your excellent channel content. I have two questions of the HX711 interface. Why do you shut down and reopen the chip after every read cycle? Is is to conserve power? Secondly I have a very nice weight cell originally from a fish weighing scale. It is however very sensitive to temperature changes (maybe it is only half bridge?). Therefore I would like to use the B channel to monitor the temperature. Does your HX711 library have a provision for channel B read?

[@harrilumme1875]

Actually after studying the datasheet of HX711 I went on to test the library and it seems that if you simply make a call scale.set_gain(32) the next reading automatically comes from channel B. When you call scale.set_gain(128) (or 64), the next reading is from channel A.

[@AbiChess.tricks]

Hello sir, why cannot we connect the load cell directly to the ADC pin of ESP 32 . Why we need HX711

[@AndreasSpiess]

Because of the small voltage differences

[@dmurphydrtc]

To circumvent my original issue (as outlined below), would it be possible to get a copy of the code as presented at the 9 minute mark in your video. I'm only interested in the scales side of things and not OLED or MQTT. Ta.

[@AndreasSpiess]

You always find a link to the code in the description of my videos

[@bdot02]

Coming to store shelves near you next year: iot cat/dog food bowls. I just know it's going to happen. It is a great idea

[@AndreasSpiess]

Thanks!

[@franzmaurer2744]

Would like to measure a beehive (25-40kg). Found a set of 4 body scale 50kg load cells (half bridge). Is it correct that when using 4 of these the max weight to be measured is 200kg? If true, shouldn't I use other load cells having a 10kg maximum. That would correspond better to the 25-40kg range of the beehive. Problem is that I did not yet find these 10kg load cells in a set of 4. What would you choose for a beehive? Franz

[@AndreasSpiess]

Maybe you watch my newest mailbag. there, I had smaller load cells

[@venkateshe7506]

Shouldn't cost more than the cat itself... I laughed like anything.. Good video once again.

[@AndreasSpiess]

Thanks!

[@bernard-charlesbarrois5265]

Hello Andreas, I come back to you because I have problems with the HX711 but this time it's on a Raspberry: the signal has a pulse width apparently longer on a Raspberry than on an ESP32. Have you ever tried the HX711 on Raspberry? Did you have signal problems? thanks for your help

[@AndreasSpiess]

I never tried it on a Raspberry.

[@ThomasHaberkorn]

Hi , very useful video as usual. I have a very basic question about the HX711. Its datasheet claims for it to provide 24 bits of resolution. This would result a "value range" from 0 to 2^24=16777216. Is it possible to get such a "high digit" number from the HX711 library? Would be interesting to determine the effective number of bits when shielding measures are applied.

[@AndreasSpiess]

AFAIK Integers in Arduinos are 32 bits and I assume you read 3 8 bit values from the chip.. So it should be possible. I never checked the library. How many bits are useful (accuracy) is a different thing and has to be measured in your setup.

[@diydsolar]

Hi, as always great video. Do the ESP32 consume less power when you change its frecuency? how many different frecuences you could choose? Regards

[@AndreasSpiess]

1. I would assume it uses less power but did not try. 2. You can choose about 4 different frequencies, the lowest was 2 MHz

[@yomboprime]

Hi Andreas. Do you think a smaller version could be used in a small robot clamp to measure the force which with the robot holds the object?

[@AndreasSpiess]

Why not. They measure all kind of forces

[@alejandromonsalvek.2014]

Hi Andreas thank you so much for your videos! You're awesome and the content is great!! I'm getting one issue though following the steps in the video, when changing my ESP32CAM speed, with the same code you showed, I'm getting this error: 'RTC_CPU_FRQ_80M' was not declared in this scope Any advise on how can I fix this? Thanks!!

[@cymeriandesigns]

A lot of work went into this one, so thanks. I'm guessing the weight reading is done at large intervals or there is some sort of averaging, otherwise the forces that occur when the cat eats would generate false indications of empty.

[@AndreasSpiess]

Of course. And it is no hurry. So you can also wait for a few minutes till you transmit the message.

[@microsoftbizappsfico]

Hi Andreas, You video about the weight measurement is great. I would like to do something similar - without a cat 🙂- and weight something that has a very light weight (< 1 gram). Can you recommend any sensors that can measure such small weights?

[@AndreasSpiess]

I do not know how to do something like that. Because it is mechanically challenging it is probably easier to buy a commercial device and hack it. Maybe you can use a sensor I used and add a long lever?

[@Peter_S_]

Cat videos are always a plus. Cat + 24 bit ADC is extra cool. Could you determine how many of the 24 bits were above the noise floor?

[@AndreasSpiess]

1. "cat 24 bit ADC" provides 400'000 hits on Google. Most of them without an animal ;-) 2. I did not look at the noise. Just look how accurate it counts the pieces. I assume, there cannot be a lot of noise.

[@Peter_S_]

🐈❤️

[@indrawanarifianto5049]

i think its very intersting, and i have made it with your tutorial, thanks but i just want to ask you, when i try to put a different food ( different weight) i can't get unit again like before, do I have to re-calibrate again in my opinion it is very teleport because I have to reprogram again? is there an event to always know the amount of unity for different types of food which certainly has a different weight ??

[@AndreasSpiess]

Of course, the computer has to know the weight per unit if you want to display units. Maybe you store several different values and add a few buttons to chose?

[@indrawanarifianto5049]

@@AndreasSpiess thanks you

[@deangreenhough3479]

Back again and just the information I needed :-)

[@AndreasSpiess]

This happens sometimes to me, too. I have to watch my own videos because I forgot how it worked ;-)

[@RichardEricCollins]

Great video. :-) loved the adc should not costs more than the cat joke. Lol.

[@AndreasSpiess]

:-)

[@roidroid]

Will you add an unpierced washable inner bowl?

[@roidroid]

Well spotted, sigh. It's not uncommon on KZbin for suggestions to be interpreted as direct insults, TBH i sometimes forget whom i need to be careful with and who's safe.

[@AndreasSpiess]

I wanted to do a project with strain gauges and we have a cat. So, I thought, the video will be much more successful if I combine the two :-) So, I did not care too much about that. I think it would be easy to just put a small washable bowl inside the one I mounted now. BTW: The "bowl" is a part of wastewater plumbing left over from my LoRa node project

[@AndyNicholson]

My Personal KZbin Content Checklist: 1) Cats - check 2) "Tech" - check 3) Genuinely interesting topic - check 4) No "tuber vlogging" - check You, Sir, have won!!! I love your videos, thank you for taking the time to make them, and keep them coming :)

[@AndreasSpiess]

+Andy: lol and thanks. My list only replaces "Cats" with "no live session".

[@Johndeerepullingteam]

Hello i'am trying this script to feed my chickens. But i can't find the soc/rtc.h library can you post a link? and do you know if its necessary when i use a Lolin nodemcu V3?

[@AndreasSpiess]

rtc.h is ESP32 specific. Maybe you try with the ESP8266. I do not know if it works, but the chances are high.

[@GRBtutorials]

Good video, but there's a very common physics misconception in your video: you said strain gauges can measure force and can't measure weight. But that's wrong, because *weight is a force* . What you can't measure directly is *mass* , which is determined by the weight of the object in a certain place (in this case, Earth). But a balance calibrated for Earth wouldn't work in the Moon, because the weight of the same amount of mass is different. Mass is constant. Weight isn't. Apart from that (which doesn't really affect what you said in the video, since you calibrate against a known weight anyway), the video is very good.

[@AndreasSpiess]

Of course, you are right. I mixed things up

[@ravishanker9014]

Very Informative...God bless you...Keep it up

[@AndreasSpiess]

Thanks!

[@ravishanker9014]

Andreas Spiess Hello from India

[@eld0ntyr3ll]

Hi Andreas, great video again, a couple of questions. I don't think you mentioned which strain gauge you decided to use for this prototype and if there was a reason for choosing that gauge rating ? Also i've never used such gauges or analog bridges, nor played a lot with ADCs and i had to look a bit around to try and understand that "F.S" (full scale?) unit, maybe some details about ADC precision/limitations in your next ADC video, i don't remember if you covered ADCs in a previous one. I'll try to apply that to my mailbox to check if mail has really been delivered, yeah we're all someone else's cat :)

[@AndreasSpiess]

1. I think I mentioned that you get load cells for different weights. This weight is the full-scale weight. 2. I used a 2 kg load cell, which is too much. But I did not have another one. I would expect that a 200 g cell would be more precise for smaller weight. 3. So far I have no ADC video planned. But you never know...

[@sledgeHammerRulez]

Hi Andreass, just stumbled on this "old" video of yours looking for a weight sensor and ESP. The idea is that with this weight sensor, I can estimated the amount of filament om my 3D printer. Should be possible ... I think :S. Big kisses to the star of the video :p

[@AndreasSpiess]

It should be possible to measure the weight of the spool and calculate the rest of the filament if you use similar spools to estimate the tare.

[@nrdesign1991]

12:10 What's even better than a straw, is a single spaghetti noodle. It's thinner, and therefore much more interesting.

[@AndreasSpiess]

Thanks for the tip:

[@mattiasdesmet]

Hello, great video's, I learn a lot from them. Can you give a pointer how to use the HX711 without Arduino libraries? I use CPP projects in Eclipse and can't find a library for HX711 without Arduino support.

[@AndreasSpiess]

No, I never searched for one. This is the reason I use Arduino stuff...

[@RambozoClown]

Very cool project.

[@AndreasSpiess]

Thanks!

[@joeybushagour2612]

Hey Andreas, great video! I had no idea about slowing down the esp32, I'm sure that will come in useful! One quick question I had, why did you use an ADC instead of an operation amplifier?

[@AndreasSpiess]

Because these are very specialized chips and dirt cheap ;-)

[@anumsheraz4625]

Awesome as usual! Keep up the good work

[@AndreasSpiess]

:-)

[@thesimbon]

Isn't it better to use a shielded ADC? I'm currently in the process of assembling a uA current meter using the same ADC but shielded version.

[@AndreasSpiess]

I do not know if this helps a lot. I would first reduce the length of the wires from the sensor to the ADC. But it does not hurt.

[@ferencszabo3504]

Hi Herr Spiess, i wonder how often it is nedded a calibration for the scale? Does it reacts to temperature change?And the fundamental thermodynamics law is that "the cat must stay indoor in the winter! 😁'

[@AndreasSpiess]

There are a few comments from beekeepers which wrote that it has to be adjusted from time to time. There are better elements around, but they are also more expensive.

[@ferencszabo3504]

Thanks for the answer! Your videos are very interesting and good knowledge resource for us!

[@EliSpizzichino]

Tack så mycket!!! If YT had the possibility to multiply my thumb-up I'd do it! Good humor, clear and to the point.. You are great! I've replicated this setup using ESP32 + node-red and it works! The tip about RTC it's indeed needed, it stabilize also the value of the other reading, but why the soc/rtc.h is used instead of esp32/rom/rtc.h of arduino-esp32. What's the difference?

[@AndreasSpiess]

1. I do not know. 2. The library should now also support the ESP32 without my trick. I did not test it.

[@EliSpizzichino]

Yesterday I've tested the FSR sensors and are much more practical to work with, at least for my application

[@AndreasSpiess]

If I understand right, the weight sensors have those FSRs built-in?

[@EliSpizzichino]

As far as I know No. In FSR the resistance varies based on pressure. In the load cells you amplify a stress signal. In FSR the microcontroller current is feed into it and you measure the difference with the analog input. Here is a quick video I made (in italian) that show it working tinyurl.com/y68sl7te

[@royemory800]

@@EliSpizzichino "Sorry, the file you have requested does not exist."

[@jmaguilarr]

jaja, a new cat star of internet!!

[@AndreasSpiess]

Right!

[@snandan87]

Hey, can you please help me which pin for esp32 to use with hx711 sck pin,thanks in advance.

[@AndreasSpiess]

If you google you find many links (also to one of my videos)

[@patrick.lehnen]

Didn't you face the problem that if you press on the bowl (after calibration) and release the force again, that your zero is shifted? I had that problem. And couldn't find a solution. I think I used the same hardware as you (with an arduino uno). I wanted to measure the weight of playing cards. But because of the offset which occurs after applying force to the sensor it was not possible to get reliable results. Do you have any idea how to achieve this?

[@AndreasSpiess]

I do not know which kilogram version of the load cell you used. I assume it is below its capabilities. Mine has a maximum of 2kg, but this was the only one I had. I ordered now a few with lower kg (down to 100g) and I assume, they will be more precise for the small weights. But I did not do extensive tests about the accuracy.

[@patrick.lehnen]

I think I used a 100g version. but placing a weight and removing it changes its zero value. I wonder if there is a solution to that (except "guessing" when the weight has been removed completely and then tare again). In case you do some accuracy tests and DON'T face those problems, please let me know - then it might be faulty hardware. In case you DO face those problems and find a solution, please please please let me know as well! :)

[@AndreasSpiess]

I will do some tests when the new ones arrive

[@edgarvaneersel2]

I want to measure the water level in my coffee machine by weighing the water tank. If the zero really shifts, my solution will not work. I was hoping that i could hard code the calibrated values. I bought a 5kg strain gauge for a 3 liter tank. Haven't installed it in my coffee machine yet. I see this message is now 2 months old. Andreas or Patrick were you able to analyse this problem?

[@patrick.lehnen]

I think coffee is fine. I tried to measure very tiny objects (playing cards, which weight about 2g each), so it has to work very precise to detect how many cards are on the scale. But in your case you can just detect that a certain minimum weight is not present and then tare it to zero. I am sure even hard coded values will work.

[@pepper669]

Thanks for the inspiration - once again! I've just ordered the sensor *and* the HX711 board from AliExpress for - dare I say it - €2.61, shipping included as usual. Now my question: Can I use it with the ESP8266 (the speed should be about right), or do I need 2 analog inputs - I guess digital ones should do?

[@AndreasSpiess]

The digital are ok

[@pepper669]

Thanks!

[@ReevansElectro]

I know that the weight scale is temperature compensated but my question is: how do you know the cat's temperature and where do you insert the probe?

[@AndreasSpiess]

I am just a humble Electronics Engineer. So, you have to ask the Animal Doctor ;-) And I am glad I do not need to do this job because I am pretty sure she would not like it as much as eating.

[@brigittemuster9391]

Thanks for the always instructive, interesting and funny videos! as a beekeeper i would love to see a video about a Beescale that sends the measured data like weight and BME 280 weather data to a DB on the internet with Lorawan via Thethings network I wait until you start with beekeeping :-)

[@AndreasSpiess]

I often use a project to show a particular technology and hope, that the know-how is used for other applications. In this case you should find all parts needed for your project. With the exception of the mechaical part for the scale. But if I remember right, I saw some other projects for that part. Just if you want to start before I start. Beekeeping will be after KZbin. So it will probably not appear on the channel :-(

[@MarcRitzMD]

You're lucky your cat eats dry food. Wet food is more complicated. I need make a cat presence sensor that will open and close a lid on the food bowl to keep the food from pests

[@AndreasSpiess]

NRF or BLE would be good technologies for that

[@ThomasHaberkorn]

Before I fry my ESP32 Board, one question: Which pin to connect the LiPo Battery to power the MH-ET LIVE ESP32 board (which does not have a battery connector). Couldn't find useful information elsewhere. I would try the 5V Pin but maybe i shouldn't ..

[@AndreasSpiess]

4.2 volt on the 5v should not fry it. But maybe it will not work for a long time. Depends on the minimally required voltage of the regulator.

[@ThomasHaberkorn]

I will try, thanks!

[@ThomasHaberkorn]

update: when powering "non-battery" ESP32 board through the 5V pin, the program won't run. The LED's on the top side will light up tough. I will have to order a proper ESP32 board to use a LiPo with.

[@IoTLearner]

Nice video, happy for the cat :)

[@AndreasSpiess]

Thank you!

[@brmamkt]

Hello. I would like your help. I'm using an Esp32 and the HX711. I downloaded the HX7711 library from the link you provided and I also read the other links but I'm not getting it. The readings on the HX711 are always 0 or -1. I've already tested GPIos 26,25,33 and 32 but nothing changes. On Arduino Uno it works normal. Thank you.

[@AndreasSpiess]

Unfortunately I cannot do remote debugging.

[@ralfjahns3777]

I have read a little about this weight sensors but never really played with one. There should be a lot of problems e.g. repeatability, return to zero after getting bent and value drift if loaded for a long time. Have you had one of these problems in your experiments?

[@AndreasSpiess]

I did not experiment other than this video. But I can imagine such problems can occur (the sensor is aluminum). And I do not expect a lot of precision or durability of a 3 dollar sensor. On the other hand, I was impressed that it was able to count these pieces quite exactly. Maybe you need a different sensor if you load it with a constant weight.

[@pfeerick]

If they these electronic strain gauges are prone to that, the manufactures of digital scales seem to have gotten around that somehow, as this is the same sensor/principle that is in most of them... Another device that used them which you might not have expected to see them in was the Nintendo Wii Fit balance board... there was one on each corner/leg, and it used them to measure weight and movement. Surprisingly accurate, and they took a lot of abuse!

[@AndreasSpiess]

I think body scales are not critical because the weight is only on for a few moments. I could imagine that it is a bigger problem if you have the weight always on.

[@norberthartmann5075]

Hallo, ich habe leider einen datenverlust zu beklagen .. könntest du noch mal den link sagen wo die verdrahtung von vier 4 draht loadcell´s zu einer wheatstone brücke gezeigt wurde um diese dann mit einem HX711 zu verarbeiten? Danke

[@AndreasSpiess]

Das hier ist ein guter Link: learn.sparkfun.com/tutorials/load-cell-amplifier-hx711-breakout-hookup-guide

[@norberthartmann5075]

danke!, denke dann muss ich wohl so langsam meinen plan mit den vier "4 - draht 50kg loadcells " beerdigen ...

[@jumadhaheri]

Excellent video

[@AndreasSpiess]

Thanks!

[@donvukovic7440]

Very informative video, Thank You. As a strain gauge must be ZERO'd before use (or at power up) the power must be applied at all times. I see from the data sheet that the gauge amplifier only need 1.5ma, but the ESP32 is much higher. Is there a way to shut off the power and still get a correct reading from the strain gauge ?

[@AndreasSpiess]

I am not sure that the gauge has to be powered all the time. These are just 4 resistors. And my bathroom scale lasts forever on a small battery.

[@donvukovic7440]

True, but when it is powered OFF and powered back ON later, the weight must be removed to auto-zero. Like my kitchen scale. I can not leave anything on the scale.

[@AndreasSpiess]

Or you are sure you know nothing changed during the sleep. Then you can calibrate on the last measured weight. (For Beehives, for example where the weight does not move fast)

[@donvukovic7440]

Yes, I have thought of that. The chance of extra weight being added or missing would be an unknown that would be impossible to resolve. I am working on another type of measurement system that would not have that much uncertainty. We'll see how it goes. :-)

[@AndreasSpiess]

I am always interested in better concepts.

[@vitormeireles1830]

Do I have to calibrate the load every single time that I start running my program?

[@AndreasSpiess]

Maybe you can store the calibration in eeprom. Then it is not needed.

[@HitAndMissLab]

When Andreas slowed down ESP32, did he say that Serial and WiFi were slowed down or not. Its a bit unclear what he meant, because he said "unfortunately ..." and than he said "thank you Expressive ..."

[@AndreasSpiess]

+HitAndMissLab I only said, that both still worked.

[@GhVost]

Very nice video, Andreas! As always. Thank you! P.S. Your Katze name sounds a little bit russian. Very unsusual and sweet!

[@AndreasSpiess]

We have her from the animal asylum. So, we did not decide on the name. But we like it :-)

[@gazzacroy]

cool video,,love the cat too :)

[@AndreasSpiess]

Thank you!

[@robertosonzogni]

Hello, is it possible to use two or four 4 wire 100 kg load cell so I can measure 200 or 400 kg ? Tnx

[@AndreasSpiess]

Yes. But make sure that 400kg is never exposed to only one cell. Otherwise, it is bent.

[@robertosonzogni]

@@AndreasSpiess thank you, how do I connect the 4 cells to HX711?

[@AndreasSpiess]

@@robertosonzogni You have to have a HX711 for each cell

[@stationHQ]

Andreas, thanks for this excellent presentation. While you provided aparts list for this presentation you missed that for the ESP32 with the built in display. Could you please confirm the ESP32 with built-in display Keep these presentations coming! Cheers

[@AndreasSpiess]

I have a full video comparing all sorts of ESP32 with displays. There you find the list.

[@catalinalb1722]

Hello, will this run on a ESP8266? I have the Wemos D1 R1 how can I adapt the code to make it running and also link it to NodeRed raspberry server?

[@AndreasSpiess]

if you find a library for the HX711 or you write your own, you can run it on all platforms.

[@catalinalb1722]

@@AndreasSpiess I gave up on my D1 R1 and managed to upload it to my T-Beam TTGO. And got a Welcome message on the small display. I did change the pins for HX711 to 4 and 0. Since this was made to connect to a MQTT server what can I do now to store the data and visualize it on Grafana?

[@catalinalb1722]

@@AndreasSpiess Hello, I have the project running on my T-Beam ESP32. I have to comment-out the lines for connecting to the MQTT since the serial port was screaming "5Connecting to MQTT..." . I did the calibration an it shows grams. I have two questions: 1 - Do I need a payed subscription to MQTTCloud? (I just want to run it locally with the rasperry pi sd-card grafana image) and 2 - how can I set the units? I am using a load cell 2Kg max and I did calibrate it with a 41g LiPo 18650 battery. Thank you

[@AndreasSpiess]

You can use mosquitto as a broker on you raspberry.

[@catalinalb1722]

@@AndreasSpiess Hello, Yes I had to edit the mosquitto.conf file with the line "listener 1883". Now the ESP connects to the Raspberry and the LCD display is showing the value. Also, the confirmation from the serial port appears "connecting to MQTT... connected". How can I create a graph using Grafana? I am running the Grafana Image on my Raspberry. In Node-Red I do have the flowgraph Weather and Cat bow. I did set the correct IP address and ports but is showing connecting... Thank you.

[@reeseyme9613]

why not use an opamp and use its feedback & input resistor to set a gain of approx. 550 times for the ESP32 ADC full scale of 1.1V?

[@AndreasSpiess]

This is possible. If you look at the datasheet you see, that the HX711 has some additional features especially for its purpose

[@avejst]

Thanks for sharing 😀

[@AndreasSpiess]

You are welcome!

[@CrazyCoupleDIY]

Nice one, I dont have a cat but may be some day

[@AndreasSpiess]

Works also for all kind of other weighing problems...

[@BartHuitsing]

Will use this project to detect if my chickens are out of water

[@AndreasSpiess]

Cool project!

[@BartHuitsing]

In the end I used an ESP8266 in combination with two load cells: 1 for the water silo and 1 for the sood silo. I used ESPhome for convenient integration into Home Assistant. Thanks for the inspiration!

[@udith-pz4tv]

Thanks, good job

[@AndreasSpiess]

:-)