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- Опубліковано 24 лип 2024
- Let’s build a connected scale, which alarms us when the food bin is empty. Of course, we will be able to use the same principle to measure the weight of any other good like the honey in remote beehives, or even your own weight to visualize it somewhere in the cloud…
So, today we will:
- Measure quite small weights with an Arduino like Microcontroller
- We will need some tricks to do that
- Then, we will build a bowl for our cat which is capable to detect if no food is available anymore
- And we will send a Twitter alarm to our Smartphone
We will also slow down the clock rate of the ESP32 to fit the timing of the HX711chip, and will use an OLED display and an MQTT library.
Links:
Sketch: github.com/SensorsIot/Weight-...
HX711 library: Based on github.com/bogde/HX711. Please use the one in my Github. Otherwise, you will get a compilation error
HX711 module: bit.ly/2fBZ82W
Strain Gauges: s.click.aliexpress.com/e/Jqb2biU
Supporting Material and Blog Page: www.sensorsiot.org
Github: www.github.com/sensorsiot
If you want to support the channel and buy from Banggood use this link to start your shopping: bit.ly/2jAQEf4 (no additional charges for you)
Official Wemos Store: s.click.aliexpress.com/e/jUzBiIq
/ sensorsiot
/ spiessa
www.instructables.com/member/...
Please do not try to Email me or invite me on LinkedIn. These communication channels are reserved for my main job
Who is the first to buy me a coffee? www.paypal.me/AndreasSpiess - Наука та технологія
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.
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)
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!
Thank you for your nice words. Enjoy your ESP32!
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 :)
This is why we all love UA-cam ;-)
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
Thank you for your nice words!
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!
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.
Andreas, thank You for your videos - always very interesting and helpful!
You are welcome!
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...
Adding an automatic feeder is a good idea! Maybe for another video...
absolute nice video as allways on your channel ! keep up with that high quallity videos ! thumbs up
Thanks!
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.
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...
That was really cool. Special thanks for resolving the slowdown to eliminate anomolies.
:-)
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!
I also plan to become a beekeeper when I have more time. Seems to be interesting and important these days.
I would love to see progress on this, as Andreas points out, it is becoming even more relevant.
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
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).
I will test if slowing down also solves my problem with reading from a DHT22 temperature sensor...
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
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...
You got me with the cat. Thanks.
That is what I hoped ;-)
"As with all models" :-)
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?.
Richard Wenner
Ohh Richard, well said😀
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?
cored 😂 a rubbish one maybe. I like your way of thinking 👍
But that would mean we can't use our expensive oscilloscopes to measure our cheap Arduino circuits... 🤔
+3zuli: If there is a rule the exception is not far (other law)...
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).
So, good luck! You should now find the links for the products, too
Sweet, thanks ;)
Congratulations Andreas! Thanks for sharing!
You are welcome!
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!
Indeed unbelievable! I never went this far. This is a very big range!
new viewer, especting to play soon with my ESP, thanks for the videos, you are awesome
Welcome to the channel!
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?
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 ;-)
In your video you mentioned temperature compensation requirements. A Wheatstone bridge takes care of that. Nice job.
You are right.
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.
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.
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.
10:36 "as with all models she had to starve a little before her appearance" that was hilarious :D btw great video as always!
Thak you for your nice feedback!
Yes, and now cats are taking over electronics videos -- is there nothing they don't dominate?
What a beautiful cat!!! 🐈
I will tell her ;-)
great! Next level is servo motor filling the Dishka's bowl. Thank you.
Maybe :-)
Elektonik und Kätzli, fantastisch! 😍
Danke!
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 :)
Good idea!
Awesome as usual! Keep up the good work
:-)
Thank you! You save my project!Great Video!
Glad it helped!
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).
I think your idea about a feeder is a good one. Thanks!
Sunday Morning 6 o clock 😃👍🏼 at the Point ... accurate like a Swiss clock 😉
Früher Vogel fängt den Wurm? Oder gerade aus dem Ausgang gekommen :-)
Andreas Spiess 😂😂😂👍🏼
Back again and just the information I needed :-)
This happens sometimes to me, too. I have to watch my own videos because I forgot how it worked ;-)
thank youuuu!!! you fixed my project up with the esp being too fast for the HX711!! i was pulling my hair here haha)) thanks!!!
You are welcome!
Hallo Andreas, deine Videos sind Klasse.... Danke! Feri (Thurgau)
Gern geschehen!
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.
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 ;-)
Nice video, happy for the cat :)
Thank you!
I like the historic pictures! It's good to give some honor to those who invented and discovered what we use today.
Thanks for the feedback.
Very genuine projects.
Thanks!
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!
You are welcome!
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.....
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
Thanks!
In the last 5 years I have seen many UA-cam 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...
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 ;-)
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
She is already old. So, eating is more important to her...
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.
I answered in one of your videos
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.
Thumbs-up for your cat being the spitting image of my old cat Stanley (RIP)
Hope he was also such a nice animal.
Excellent video
Thanks!
Very cool project.
Thanks!
cool video,,love the cat too :)
Thank you!
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 !! -
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!
:-)
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!
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.
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...
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.
+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/
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.
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
That is what the call "branding" ;-) Thanks!
Very Informative...God bless you...Keep it up
Thanks!
Andreas Spiess Hello from India
Thanks for sharing 😀
You are welcome!
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?
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.
🐈❤️
I love Wheatstone bridges.
:-)
Very nice video, Andreas! As always. Thank you!
P.S. Your Katze name sounds a little bit russian. Very unsusual and sweet!
We have her from the animal asylum. So, we did not decide on the name. But we like it :-)
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.
Of course. And it is no hurry. So you can also wait for a few minutes till you transmit the message.
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
I have a full video comparing all sorts of ESP32 with displays. There you find the list.
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!!
Shouldn't cost more than the cat itself... I laughed like anything.. Good video once again.
Thanks!
jaja, a new cat star of internet!!
Right!
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 :-)
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 UA-cam. So it will probably not appear on the channel :-(
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
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.
Great video. :-) loved the adc should not costs more than the cat joke. Lol.
:-)
Unsere Katze hat sofort ein Build bestellt. (Die ist auch langhaarig....) Danke für diese nette Idee...
War eigentlich nur als "Demonstrator" für das Thema gedacht. Unsere Katze braucht nähmlich eher das Gegenteil von mehr Futter...
:-) Meinung meiner Frau: sowas brauche wir nicht, die mauzt so laut rum, wenn der Topf leer ist, das schafft kein Smartphone.. :-)
:-))
Thanks, good job
:-)
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?
Because these are very specialized chips and dirt cheap ;-)
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?
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.
Hi, as always great video. Do the ESP32 consume less power when you change its frecuency? how many different frecuences you could choose? Regards
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
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.
No, I never searched for one. This is the reason I use Arduino stuff...
Hi Andreas, as always really interesting and very well made! .. Thanks a lot ... and btw "deisch I mi oder is dei kaz ziemlich gwambad ?" ;-))
Sind nur die langen Haare. Drunter ist praktisch nix (das ist die Ausrede meiner Frau wenn sie der Katze nicht widerstehen kann und sie füttert...)
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.
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.
"it should not cost more than cat itself".. lolll lol
Yes!
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
NRF or BLE would be good technologies for that
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 :)
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...
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?
The digital are ok
Thanks!
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! 😁'
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.
Thanks for the answer! Your videos are very interesting and good knowledge resource for us!
Hello sir, why cannot we connect the load cell directly to the ADC pin of ESP 32 . Why we need HX711
Because of the small voltage differences
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
Maybe you watch my newest mailbag. there, I had smaller load cells
Can you start including time to complete projects or man hours ? I always like knowing the research and build times
I better do not do this... Because I would then see that I do not sleep enough ;-)
And it is often not possible because it is not a linear process. What I can say is, that I need about 10 hours production time for one 15 minute episode. Without doing the project.
Love it!
:-)
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?
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?
12:10 What's even better than a straw, is a single spaghetti noodle. It's thinner, and therefore much more interesting.
Thanks for the tip:
Will use this project to detect if my chickens are out of water
Cool project!
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!
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.
You always find a link to the code in the description of my videos
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 ??
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?
@@AndreasSpiess thanks you
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?
Why not. They measure all kind of forces
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?
1. I do not know.
2. The library should now also support the ESP32 without my trick. I did not test it.
Yesterday I've tested the FSR sensors and are much more practical to work with, at least for my application
If I understand right, the weight sensors have those FSRs built-in?
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
@@EliSpizzichino "Sorry, the file you have requested does not exist."
Will you add an unpierced washable inner bowl?
Well spotted, sigh. It's not uncommon on UA-cam for suggestions to be interpreted as direct insults, TBH i sometimes forget whom i need to be careful with and who's safe.
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
My Personal UA-cam 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 :)
+Andy: lol and thanks. My list only replaces "Cats" with "no live session".
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.
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.
Good idea and nice video, but my cats already have embedded food alarm.
Nature always wins ;-)
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 ..
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.
I will try, thanks!
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.
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 ?
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.
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.
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)
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. :-)
I am always interested in better concepts.
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?
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.
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!
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.
This cat does not look like that project was neccessary.
+cody83462 :-)) You are probably right. But as an excuse: You have to subtract the long hairs (this is what I always hear from my wife if I complain about the fat cat).
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.
Of course, you are right. I mixed things up
Perhaps it makes also a good solution to bit-bang the interface, instead of slowing down both cores to 80MHz?
It seems no more necessary with the newest library. I did not try
@@AndreasSpiess Ich verstehe. Gut zu wissen jedenfalls. Ich hatte bisher nur mit PIC32MXxxx/PIC32MZxxxx/PIC24FJxx und diversen ATMEL Controllern aus der ATMega/ARM Serie 'herumgespielt'. Doch ich habe mir einen Haufen ESP32-WROOM bestellt, um die mal ein wenig auszuprobieren. Jedenfalls Dank für die Antwort! Beste Grüße aus Berlin!
I see. Good to know anyways. I'll soon get into this ESP32 stuff and certainly have a look into it's Serial/SPI/I²C interfaces and all it's aspects along with ESP32. Thank you anyways for the information. That might be helpfull to know about. With best regards from Berlin, have a nice weekend!
You don't have to slow down the cores. A custom SPI read with delays is enough. They did that with shiftinslow and indeed it works fine.I did some quick tests a while ago but HX711 is a very bad chip and moved on to ADS1232 which also needs a slight delay (os library/project: gitlab.com/jousis/espresso-scale ).
Nice one, I dont have a cat but may be some day
Works also for all kind of other weighing problems...
sehr ausgezeichnet
Danke!
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?
This is possible. If you look at the datasheet you see, that the HX711 has some additional features especially for its purpose
Andreas, 80 Mhz is still to fast, mine started working at 40 Mhz, but also thanks for the hint.
You can also set the speed at the arduino compile data at the desired speed.
I even think the fixed the issue in the library.
Wow.. that's why I didn't managed to do this with ESP8266 maybe? The speed is also the problem?
Maybe. It was a problem here