Rotary encoder or: How to build a digital servo using an Arduino and photo sensors
ฝัง
- เผยแพร่เมื่อ 22 ธ.ค. 2015
- Table Of Content:
00:05 Introduction
00:23 Photo sensor
03:35 Sensor disc
05:49 Directional encoder
08:27 Agular resolution
09:53 Motor control
11:24 Steppermotor
14:36 Proportional control loop
16:31 Pulses per second
18:31 Motor parameters
19:37 Angular resolution / small servo
21:22 Ocilloscope plot rotary encoder
24:29 Printer motor
25:50 Linear drives
26:48 Digitale servo from a wiper motor
The project page:
www.HomoFaciens.de/technics-ba...
Thank you for another excellent video!
+Everett Bradford You're welcome and tell it to your friends.
I think your videos are the clearest tutorials out of any Arduino tutorials. I always wind up watching your videos when I want to learn new stuff.
Watched this twice now, really interesting video, so well put together and so much information covered, well done.
+bigchrisrogers Thanks! Yes, I try to put as much information as possible in my videos, thus watching them once usually isn't enough to get it all if you don't now much about the subjects I am treating. You can also read what I am talking about on my project page and you can get the schematics to build your own circuits:
www.homofaciens.de/technics-base-circuits-encoder-disc_en_navion.htm
I like the way you demo your circuits with the right angle wiring, thats pretty clever.
I fell on this video from TH-cam just auto playing, I was't looking for anything related to rotary encoders. But that little touch you do with the wiring is awesome and is a great idea, it will certainly help novices and experts alike. Thumbs up to you
All the questions I had about driving dc motors with encoders in a single video - Brilliant!!
+Google+ SUCKS BALLS - the worst forced social network It's always good to find answers...
This is such a thorough demonstration. Thank you so much for sharing this .
I definitely will watch this again and learn from the code.
+Bob Durk ...you can lean more from code by reading it. The source code is available as download on my project page:
www.homofaciens.de/technics-base-circuits-encoder-disc_en_navion.htm
I just got to know that old TH-cam videos are better than most of the new ones🙃
Thoroughly enjoyed every part of your vid
Now I know everything about servo motors. thank you. Very usefull stuff.
Thank you man, for real. Your serie of videos about encoders and optic sensors aplications is helping me a lot.
More one satisfated subscriber!!!
Beautifully explained. Complete clarity at every step.
I would like to thank you for this video. I have learned so much from this!
Great video, I roughly knew how these things work but now it is crystal clear.
Many thanks!!
You can buy some encoders on the market but when they fail or you have issues it is great to understand the principle. Great video. You just told about PWM and PID control also. A broad beginning to it. Love it really enjoyed your video.
+killerbeenl Yes, knowing what devices you are using is always helpful. Some more about PID is in my video covering the Arduino Uno:
th-cam.com/video/PQ1FBcQT0AI/w-d-xo.html
It's a fascinating subject, thus more chapters might follow...
Excellent overview of servos. Thanks!
Just what I need, how to switch my old racing wheel imprecisse poty for an accurate encoder.
Even more, it even shows the concept behind force feedback.
Love it, simply perfect ;)
Dude having a table of contents is rad. Awesome work I'm gonna subscribe
This is what I need for my new project, great!
Excellent display of using a Photo sensor and a Arduino. I had lots of questions. You just answered all of them. Thank You.
+King Red Leg You're welcome!
Super great presentation! Thorough coverage and simple explanation.
Here are some stars: ** ** **
Thanks.
I really like that u are using lot of salvaged parts in your projects and test setups. Its helps to understand how other machines works like printers etc... thnx for sharing
+Fortzero You're welcome! And: share my project(s) with your friends.
Impressive how you go from simple idea and escalate to sophisticated one in easy to follow steps.
Thanks for the great video.
+Mohammed Algailani ...looks like I can't create short videos ;)
Your demonstration of principles is so effective I have sent your video links to young children who can understand and begin projects in no time at all. Great work!
Thanks for sharing. More videos using old printer parts will follow - stay tuned!
Thank you so much!!! its been so easy for someone with little knowledge
Thank you for sharing! I'm a non technician and able to understand most of the things you explain. I enjoy your videos a lot :) Always pleased to hear you'll be back ;)
+Matschase Who ever is able to understand what I am talking about has been turned into a technician. Start to build one of my machines and you are also turned into a maker (or a "Homo Faciens" as I call that species).
I'm so excited to see this video so interesting and so guiding!!! Greetings from Puebla Mexico!
Really great stuff- packed with info! Very good job!
Excellent description. I understood perfectly, thank you. Subscribed.
Thanks Arnold S. !
"Consequently eight signals were counted"
Thanks for a great video. It's so clear and well paced. I love the "rough" electronics and mechanics you do. Ist aber wirklich wunderbar, Danke! :)
+Bernhard Hofmann I don't have enough time to give my machines a smooth design ;)
Die Einfachheit animiert mehr Menschen zum Nachbauen - bitte gerne!
+HomoFaciens For the non-German speakers, he said that the simplicity encourages more people to try this as well. I completely agree; that's what draws me to it and makes me think I might also be able to make something. I particularly liked the progress of your video as well, showing the issues you might encounter (IR light, overspin, accuracy of gears, etc.) and how to overcome them.
+Bernhard Hofmann That's it! I am sure you are able to make something and so to become a maker, too (or a HomoFaciens as I call that species).
+HomoFaciens You realy do that with your "Barbarian" (not bavarian) aproach to solve problems. You shows that you don't need to buy expensive partes to archieve success.
But if you use a power enought controller with a windshield wiper motor and a high precision sensor disk from a printer (free from garbage) we can archieve "CNC precision" and high power to build a CNC???
Here in Brazil is cheaper to buy a windshield wiper motor than a stepper motor!!!
+Vilmar Antônio Moccelin Júnior Yes, you can build a CNC with windscreen wiper motors, but I suggest to start with a low power version (you can use the motors from printers):
th-cam.com/video/5rQ4xKRfXts/w-d-xo.html
The precision depends more on the build quality of your mechanics than on the resolution of the sensor disc.
Excellent video! Thank you for sharing.
Your videos are so awesome. Thank you!
Great video, love it!
very helpful video. I will be watching it many more times for sure.
+builtrodewreckedit Yes, most of my videos provide a lot of information that can't be absorbed in a single run.
excellent video !!! .. it cleared a lot of fundamentals to me.. !! .. Thank you very much for this video..
I really enjoy your videos.
Hats off to you, Norbert, on a thoroughly made and highly informative video! How do you get the time to do all the work?
+Aditya Mehendale Thanks! Yes, many hours passed by while creating this video. I don't count the hours/days/weeks...
el tipo es un genio
Excellent video. Well done and thanks for the effort!
helpful tutorial and supply a lot of things fundamental of encoder, thank you !!!
Very helpful video. Thank you for sharing
Awesome!! You can bet on it, "I'll be back" as well! :-)
I Love the demos and the straightforward way you explain the "steps".
The software code (for me) is going to be the tough part.
Your apparatus' and lighting are superb for "laying it out".
Thank You. (You KNOW you sound like him... sorta) :-)
+jlucasound
There will be chapters about programming GPIOs (Physical Computing) in the (not so far) future on my project pages - stay tuned!
excellent demonstration!
This is awesome. Highly educational. Truly inspirational.
+lowendguru I like to inspire ;)
Man I don't know if I said thank you already somewhere else on your channel, but just in case I didn't, THANK YOU so much for all this amazing information!!! I still have a looong way to go and a lot of learning to do, I'm just starting to understand the very basics of electronics. However I'd really like to get to the point of being able to reproduce some of what you have done here, especially to re use the sensors from old printers to have an extremely useful recycled possibility.
If I manage to do it, I will make some videos and hook you up, but it is at least a few months away still!! Danke!!
Thanks! Keep tinkering and create new things. Your skills will grow over the years same as mine do with each new project.
Very good and thorough video . Thanks for taking the time to go into details.
+XerotoLabs Yes, going into details eats most of my time. Thanks for pointing that out.
Just keep up the hard work
Thanks for sharing
Wery nice and big great work! Thanks!
You're welcome! Another video about rotary encoders (how to make them more compact) is under construction - stay tuned!
fantastic. thank you so much. you are a natural educator.
You are the best! Thank you!
great video, clear to understand and very informative - will definitely put this into practice - danke HomoFaciens
Bitte gerne.
Brilliant video on encoders, thank you .
+roy douce You're welcome!
Super video- Exceptionally educational and precise. Great that you do it with home made stuff so that we get to see the technique rather than feel mystified by the tech aspects.. I watched this video and liked before- now I have subscribed, Thanks for your effort!
You're welcome! There is nothing mystical in science and technology. It's my mission to show that ;-)
Very good! I liked learn more about step motors and control them.
excelent video. thanks
Very cool! Really appreciate each of your videos. They're very informative and have an easy to follow logical flow. Cool that you can get that much speed out of the optical encoder using an arduino. I wonder what RPM you could get using a raspberry pi with its higher CPU clock speed. Thanks again for the great vids!
+LogicGodTV The Raspberry has a higher clock speed, but no realtime operating system, thus it won't be faster but slower!
HomoFaciens I'm pretty sure there are a couple of real time operating systems for both raspi and the more expensive beagle bone black. The BBB seems to be better suited to robotics, sensors, mechanics, and processing of that kind anyways, there is CNC controller software for BBB but not raspi anyways so I would recommend that one.
man you are the rock-star i love your voice.....you look like more mechanical engineer rather then electronics one
Sehr schöner Aufbau
+norm1124 ...weniger schön, aber funktionierend. Danke!
Magnificient education video! Thanks
thank you for an awesome, very informative video :)
Amazing indeed. Keep the amazing work going on.
PS. I realized you published on 23rd December. This was your Christmas present ah!
Thank you! Great Work as usually!
+Alshira Alshat You're always welcome!
Sir you truly rock, what a great set of information .. really nice :-)
Great video! Thank you very much.
Thanks for your generosity!
+Wee Kata You're welcome!
Your videos are amazing for our students. Best wishes from Pakistan
Great to know they are used in education, because that's what I recorded them for.
Best wishes from Germany!
Hola Amigo:Te felicito por tus trabajos, soy profesor de escuelas técnicas y trabajo con hardw y softw libre, por lo que implementaré algunas de tus ideas.Tambien hicimos un clon de arduino y emplearemos el Pinguino 18f4550.Gracias por compartir!.Saludos de Argentina.Te compartiré nuestros avances
that was very interesting Ty for sharing
+Waffenschmiedin x You're welcome!
this has being great thank you
thanks dude for this video u give me every thing about rotary thanks once again
Awesome Video, Thank you very much for it, Greetings from Monterrey, Mexico.
Hello Norbert Heinz
Many many thanks for your time and tutorial video!
It's a great tutorial I've ever seen...I'll be patient for the program tutorial
+khymem MU You're welcome and: stay tuned!
Best video to understand encoder 👌👌👌
Cool, like your style, passion.
Excellent video!
Excellent, thank you. But didn't you think of sensors from optical mouse? You can place them in front of simple wheel and they seem to give precise results. Very grateful for your reply.
thank you.... grate video
Many thanks for this video.
+nejat karaca You're welcome!
gracias por proyectos, si que sirvieron mucho
very informative!!!
Hi many thanks for your fantastic video//Magnus
Very nice. Well done. Thank you.
Great video. It doesn't get much better than that.
+InnaSoulSounds Thanks, but there is always something to improve...
através destas explicações vou fazer meu projeto de rotor de antena de radioamador
thank you i learned alot .
Excelente video, felicitaciones.. uno aprende mucho con tus videos y das buenas soluciones a problemas de falta de recursos..
puesto que usar DC motor en ves de steeper motor.. congratulatios!!!!!
+MrAlbrtvg vizarreta
You're welcome!
Excellent video.
+notionSunday Thaanks!
Fantastic video....very thorough explenations,just what i was looking for,for my project!Thanks!
+babis600 You're welcome!
+HomoFaciens i am trying to compile your sketches to the arduino but i keep getting a sketch\commands-host.c:15:21: fatal error: termios.h: No such file or directory
#include error.What is the problem?
+babis600 Your Arduino IDE opens the file "commands-host.c" in a second tab. Close that tab so that the only file open is the *.ino and try again.
+HomoFaciens yep...you were wright.Thanks for that!
Very informative.. Excellent video learnt so many things...
+Ashwin Thirunahari ...this video was meant to teach - mission accomplished!
Always entertaining and very informative videos, thanks for making them!
I will try and build a rotary encoder soon.
Where did you learn all this about electronics? Electrical engineering master?
+Daniel W I learned the basics about semiconductors during my education as physics laboratory assistant long ago...
Спасибо за ваш труд!
+ACIDITYRAIN You're welcome!
This is awesome, clear, easy going, to the point. Thank you very much!
I am thinking about making my CNC with just Arduino UNO, nothing fancier , no motor shields. Two wires from digital to MOSFETs per motor (back and forth movement), one gnd from Arduino to all the motors, one signal from rotary sensor to analog per motor. This way I should have capacity for 6 axis from single Ardiono UNO. I don't really need to detect which direction motors are spinning since I must already know. I spin them! I only need to count number of steps, incrementing and decrementing depending on which MOSFET I am using at a time, calculating distance from angle and thread, recursively increasing interrupt periods and toggling direction if I overshoot until I get to where I want to be. Awesome tutorial, you are the best.
You definitely need two sensors per motor. There is always overshooting: you can't say the motor starts spinning into the opposite direction as soon as you swap the polarity. Inertia causes the motor to continue spinning into the 'wrong' direction before following the new command.
Creating an h bridge from nothing but 4 transistors is also a bad idea. There is shoot through whenever you switch polarity of a half bridge which might destroy your transistors. Especially MOSFETS are killed instantly when the current is over the limit.
My CNC series starts here:
homofaciens.de/technics-machines-cnc-v0-5_en.htm
Thank you for your answer. I don't think I was being clear. Let me try once more:
First, I employ one sensor and count number of transitions. I want to move axis Z by 100 steps. Motor overshoots and moves it 103 steps (if I fail to tune the motor run with interrupts). I know I overshot, out of one sensor.
Second, I need no H-bridge. I will connect one digital pin with one MOSFET gate, operating one circuit running a motor, and second digital pin to second MOSFET gate to second circuit running the same motor backwards. I will activate one mosfet if I want to spin one direction and second if I want to spin other direction.
Never mind about my previous comment. I drew a sketch to show what I mean and I found short circuits. I added more transistors and guess what I invented? An H bridge... Yes, that is me. At university I discovered integration by parts, later I realized that weightlessness could be achieved if something spun Earth fast enough so that the centrifugal forces would negate the gravity, yes, it was 10.2 kmps, and then I noticed that light emmited by lamps correlates in spectrum to the light put off by flame test, and from there I rediscovered magnesium lamp. Next time I will listen to ZZ Top's ME SO STUPID like ten times and then will I post something. Sorry for that. Thank you very much for suggesting the diods with mosfets, I think I will greatly appreciate it soon enough.
...you will never ever forget what you have learned by reinventing the wheel ;-)
I will support you. I can't do so right now but I will. I am getting my CNC ready. It is scheduled on March. It will be Arduino uno, 1 photo sensor per rotary encoder connected to digital pin. I will use BTS7960 and my H-bridge, whether it is an H-bridge or not, 'I am not sure:
Battery: B+, B-
Motor: M+ M-
--------------------
wire1: B+ -> M+
wire2: M- -> B-
wire3: B+ -> M-
wire4: M+ -> B-
One transistor (T1 - T4) on each wire.
transistors T1 + T2 go to one digital pin
transistors T3 + T4 go to another digital pin
The rotary encoders will be made of clear disks plus silver coated vinyl foil with slots cut into it by cutiing plotter. Recently I worked on the sw side mainly. I have my CNC driver ready up to the point where it knows a correct sequence of steps (for example motor 1 step +1 motor 2 step -1 motor 3 step 0, motor 1 could go +1 +1 +1 +1 +1 motor 2 coudl go -1 0 -1 0 -1 0..., depending on vector of travel). Arduino is connected to my computer and it recieves and serializes instructions form USB port, it calculates vector of travel from where it is (remembers its position from previous instruction), turns it into the sequence, cycles this many times as Arduino can only digest very few cycles at a time otherwise it bites its own tail, eventually when finished with all the steps in intruction Arduino rings my computer which sends it another instruction and so on. Now I am working on CAM, I have very special shape to make at an extreme precision ahead, I need a special CAM that can handle meshes, not vecotrs, plus I want to test my own tool path type, but once I have my mold I will start producing arrow vanes which can and will be sold all over the place eventually so I will have means to support you. Not yet. I am a janitor.
Felicitaciones, muy buen trabajo.
+feo3h2o Gracias
I was wondering why you did not use the windshield wiper motor on your DIY CNC project, seems the extra torque would be beneficial.
+Kirk Nelson Sometimes, extra torque is very destructive. The good thing with the low power motors in my CNC machines is that they are not self destructive if something goes wrong and trust me: a lot of things go wrong if you are new to CNC and especially if you try to do some coding around those machines...
guessing you gave it some thought and rejected the idea for safety then. I was mostly thinking of your early cnc videos when you were having problems with the brushes on the motors burning up.
+Kirk Nelson If you know what you are doing, it's worth spending some days trying to build a very solid wiper motor CNC.
God dammit man! I Admire you! Keep the good work! :)
is this arnold?
excellent !- subscribed !
Great video!!! thx
Very good!! Thanks you! Danke!
Great video, thanks.
+Robert Klauco You're welcome!
thank you master
I understand and can speaj German (since im from germany) but only until i was 6 so i cant write it well. Keep up the awesome videos and keep inspireing others to create and experiment with engineering. Also, its amazing how you upload every video in english AND german. At the moment im building a 3 axis cnc machine from cd-rom drives based off of your plotter and Tinkernuts 3d printer. Keep on making amazing vids
+Vincent Leyhausen (Maker and Gamer) Thanks for all the good words.
A machine using steppers from old optical drives is a good point to start CNC.
Viel Spaß beim Basteln!
One of the motors broke so i only have 2 :(
+Vincent Leyhausen (Maker and Gamer) You could use a micro servo to lift or lower the pen.
+HomoFaciens i was going to do that but i would have to buy some and i dont have money
+Vincent Leyhausen (Maker and Gamer) Another way was using a low power DC motor (e.g. that of the CD tray) and activate that motor to lift the pen and deactivate the motor to lower the pen by gravity (or a spring). Or using an old relay.