Ah Chris the Pico has a lot of potential for young ones & us older humans. I like how you mix the practical/coding into an episode & make it enjoyable for all ages.
Zebras and giraffes, virtual puppeteering... This video is both hilarious and educational at the same time. I can't believe it's 17 minutes long, it felt so short!
I've got 7 so far! Plus a couple of Pimoroni Tiny 2040. Along with loads of Arduino Unos, Nanos, Megas and Pro Minis, and a few ESP32s, ESP8266s and Seeeduino Xaios. Buying one microcontroller is the start of a very slippery slope!!!!
Hi Chris, how’s thing in the UK? Today’s video is going to be a hit for the new programmers of all ages. Easy to follow instructions , and good project ideas. Time for me to head over to my work bench and get started. See you next weekend.
The dithering can be fixed using a simple closed loop controlling approach. That would be a very good introductory example to Control Theory using the Pico.
@@marksterling8286 losing.......loosing...........we know by now how autocorrect sometimes makes our text somewhat inaccurate, so it is worth checking before posting. You may be very experienced in giving commands to computers , so will appreciate accuracy in coding.
You should always place a small (10nF) capacitor on ADC inputs to micros to give something to charge up and dominate the internal sample and hold circuit capacitance. What you get is the result seen here if you don't.
What i liked the most are the sounds that supports the visual effects of the LEDs after pressing the switch, even if my limited python abilities prevented me from identifying it in the code base.
Back in the 1990s, when I worked for an industrial controls company, I learned about servos and something called a "dead zone". Programming in a Dead Zone eliminates jitter. So it really has nothing to do with your potentiometer, instead, it is the nature of servos. It's amazing to me to see you using $200 worth of hardware that can replace a Programmable Logic Controller (PLC), that back in the '90s, cost tens of thousands of dollars.
Those PLCs were a bit of a rip off. They were just 8 bit micro controllers with some inputs and outputs and a simplified programming language. Late '80's through the '90's we would do the same thing with a Z80 and some code written in C. The advantage of a PLC was the electrician could program it.
Chris I'm so happy you did this video. I think you're the only person I know who has done a demo without just flashing the LED. My mind immediately went to, how supplement the code to stop the jittering...😊...I was totally enthralled. Maybe round the value before passing it to the servo. 😉 Love the videos as always.
Another great video for those of us who are not truly computer savvy. You make the coding seem so simple and enjoyable. This inspires me to tear down old electronics, raid the parts store of its switch inventory, pull out a soldering iron, and buy a herd of Picos for the different joints of a few intended puppeteering projects. Nice work. Thanks!
Thanks for your videos. I have enjoyed them for a while. Vintage pot and vintage breadboard (like many I own) with a dignified aged cream color from the original white.
Good job! You just demonstrated common problem with potentiometers... they decay with age and add noise but even new ones do that. Thats why audiophile way is to replace it with ladder resistor switch.. but for your project all you need is a small capacitor in paralell across potentiometer mid and side pin and current limiting resistor in series to the gpio pin.. that would remove high frequency noise.
Another option that ***might*** reduce the jitter is to heat, or cool, or change the relative humidity, near the Pot. The jitter is presumably caused by intermittent connection to various windings in the Pot. Temperature change will affect the relative dimensions, through thermal expansion, and humidity affects accumulation of static charge on insulating surfaces near the contact regions. Great video!
A welcome return of both the Pico and Blu Tack. BTW, I don't think the age of the pot is the problem. ADCs in general are a bit jittery. Put a 10uF capacitor between the wiper and ground. That should smooth things out a lot better.
@@onjofilms It's the nature of the real world, there is noise. The only reason there is not noise inside computers is the efforts taken to design it out or at least design out the effects.
@@wayland7150 That is true. The reason for debouncing in the coding would be to save physical space on your circuit board. Both methods have their advantages and disadvantages.
Excellent work. Pixador’s comment had me fast forwarding to spot the Zebra! Anyway you showed all the basics of input and output - both digital and analog(ue). My Pico starter kit arrived on Friday so tomorrow I’m off to the shed. It was also useful showing how you connect up to the Pi 400 as it helps to get started.
Very nicely done, Chris! I like how you explain both hardware and software so we get a complete understanding of the whole system. Enabling the internal pull-down resister for the open switch is a particularly nice touch! Managing the LED pin assignments with a list simplifies the `while` loop in your Python code dramatically.
Explaining Computers... Now complete with lights, sound effects, lions, tigers and giraffes, oh my! :-) Really good fun Chris, and great code and hardware hook up examples too. Thanks for another great video.
Very very nice - I feel jealous, that already not young, It's so helpful for all who likes electronic. PS Chris - you are ready to make your own HVAC DDC for your home.
The servo jitter is likely from the Pico ADC not your old potentiometer. ADCs are not perfect and you will have noise coming from the USB port and the servo itself putting noise on the power rail. You can prove this by putting a small capacitor on the pot wiper that is going to the ADC. The jitter will still be there. If you have a scope you will be able to see the noise on the power rails.
You could also test this by making a voltage divider potentiometer equivalent using a few fixed resistors. Putting some caps over the power rails _may_ help. In any case you could do some simple filtering _in software_ to help eliminate the jitter.
@@delwoodbarker a 40 year old pot is going to have inconsistencies from corrosion, especially if you only use it a little or intermittently. You can increase the precision of them by using a contact enhancer, my personal fav is Caig Deoxit, (NASA as well as major medical equipment mfrs use it).
Hahahaaa.. Zebras & Giraffes.. you're mad as a box of frogs 😄👌 That's why your content is complete Gold-Dust. For me and the kids I work with. Got our Picos 2day. Thanks a million Christopher 🙏✨
Great video Chris, as always. I now use CircuitPython on any microcontroller that supports it. I moved away from raw MicroPython except on something like an ESP32 that doesn't support CircuitPython. On the Raspberry Pi RP2040 chip boards there is a great PIOASM assembler that can run out of the box via CircuitPython. The latest version of Thonny does a very good job using MicroPython and CircuitPython boards.
Great video, a lot happing for such few lines of code. I'm new to the Pico so I've binged a lot of videos on the Pico! One problem I had with the SG90 was it going beyond the 180 degree mark which resulted in it shaking and heating up. After adding and displaying the 'value' variable to make it visible in the shell, I could find the value that took the servo beyond the 180 and created an if statement to limit the range of the value. It did work, although there was a region of the pot that didn't work. Will study PWM and Duty cycle for a deeper understanding of the code.
Picos are an ideal companion to a Pi computer, as they are much better at connecting to physical devices than the GPIO on a Pi is. My current project uses a Pi 3B with a touch screen for controlling a Pico that will have a motor driver, servos and a stepper motor attached. I'll probably use I2C for communication, but haven't got that far yet. The Pi will give me remote control through Wi-Fi, Ethernet or Bluetooth, including the potential to stream video so I can see what I'm controlling remotely!
Good stuff. Reminds me of learning electronics back in the 1980's. The devices were bigger and a lot less integrated, but with a couple of dozen chips we could do the same thing. :-)
Brilliant introduction to micropython and programming with the Pico! Really excited for my Picos to arrive in a few weeks, it’s a far cry from my assembly code days with the 8051.
For the Servo jittering issue, easiest fix would just be to round to nearest 100, you can clearly see in the video that the jittery-ness of the values only fluctuates 100 values or so. Edit, The jittering output would make a pretty cool random string generator: sha256 the string of input^input.
Love this. İt's a perfect introduction to the kinds of things one imagines doing with a Pico. I did a show and tell video last week at work about the Pico but I should just have played this :)
I'm sure you'd have the same problem with a new potentiometer too. It's a noise issue in my opinion. A capacitor across the wiper to ground would probably sort that out.
ExplainingComputers is Concise and Clear as always! :) The servo jitter can indeed be reduced as Roger Froud pointed out using a capacitor to dampen the noise. Probably the best way. Yet, while the best software is hardware, I would still add a software value damper to the while loop which averages out the values as a fail safe.
@@TriAngles3D Exactly. My professor was teaching us these concepts but with push buttons. Called 'Debouncing', he showed us both the hardware and software way. He insisted that we use the software way though. :-)
Great video as always Chris. Thank you. I'm currently working with the Pico's little cousin, the Tiny 2040 and am trying out the coding that you explained in this video. I played around with it as well and had some fun with it. Didn't have a servo motor handy but that's okay. Will be getting one at a later time. Thanks for these videos. They're a great help and hoping you get a Tiny2040 for future videos.
Thanks again Chris, always looking forward to your videos, very informative and useful information brought to us in the usual colourful manner we like.
Nice tutorial! I've done this type of thing in "C" using an Arduino, but I've never used Python, and have always wondered if it would be easier. This gave me a nice comparison of the two languages. Very nice, thank you.
I have a project on the go to connect multiple Picos using the RFM69HCW radios (not the LoRa variants). The libraries for these radios are only available in C (they be available in CircuitPython but I believe CP doesn't support interupts, which my project needs), so I went down the C++ route a couple of months ago using the Pico SDK and Visual Studio Code. It was an absolute nightmare to setup and get working on W10 (RU-vid was my friend here), and is pretty cumbersome to use. In the last month or so RP2040 support became available on the Arduino IDE which I have briefly used just to test that it works. If the radio libraries were available to Micro Python I'd use that in a heartbeat. So much easier to use, and TBH I wouldn't miss the greater (much greater) efficiency of C++ on this project.
@@lesliedeana5142 Yes, thanks. And I like what I’ve seen of C++. Its relative inaccessibility (on the Pico at least) appeals to my inner geek/snob, it seems to be extremely feature-rich, and as you say, is fast in execution. But, and I am no expert here, Python and Micro Python, far from being the modern day equivalent of BASIC (and that wasn’t THAT bad), are also feature-rich and really nice languages to use.
Informative and very well timed, I'm learning and experimenting at the moment with controlling a matrix of LEDs with the ultimate aim of making a unique animated clock. You gave some handy programming tips, especially controlling i/o from an array.
This could headline a "demystifying servos" playlist! Also, mad props for the efficient code: I'm about to jump ship from the HMS C++ to the HMS Python. Thanks for another great video!
So, I don't know if someone already mentioned it, but the issue with the jitter on the servo wasn't caused because your potentiometer was 40 years old, but rather on the fact that the 16 bits of the ADC are not "all useful" in this scenario. You only use the entire ADC resolution to average its value on most cases, or you can discard 1, 2 or 3 bits out of it as well. I know there are some cases where you can just use the entire range, but that's also paired with an analog front end circuitry on the ADC, with matched impedances, and not a single pot connected to it. What I would suggest is to add a capacitor (100nF or so) between the output of the potentiometer and ground, and also average (or directly discard 2 or 3 bits) the raw ADC samples.
Chris great tutorial! Just what I needed to help me get the basics down so I can complete a project that I have been working on. Once again, Thank you!!!!
Your jittering servo / pot input value was more likely noise induced in the input from the servo motor brushes or the pi itself than a dirty pot. Decoupling the power to the servo either with a separate supply or simply a .1uf capacitor across the supply pins would probably fix the issue. The same can be done across the pot. Dirty pots typically go open to the wiper briefly then back to their positional value, often very quickly but the result is a more random noisy signal.
Brilliant video, Chris. I’ve been programming on the Pico since February. I like the simplicity of Micro Python, but I’ve been using the C SDK for maximum speed.
Very educational! Nice change to the usual SBC-stuff! This stuff encourages me to learn & experiment a bit with the pico and RPi sbc's. Keep up the good work! Regards, Willem
You could write code to filter out the jitter, Just average the last 50 ish potentiometer inputs before the current one and average it then add maybe 5%. If the new value is not a greater difference, continue to return the same value. If it is different, write it to a variable for the current servo position .., and it keeps sending the same value to the PWM u til significant change
Really great video Chris, i have been trying to teach my son about pulse modulation but I failed to get his attention, today he sat down and watched you video and now we are breaking out the pi zero wh connected to a breadboard and a couple of servos, he is trying different code as I type this. I have not got a pico yet preferring to ssh onto the zero. We both wondered with the earlier powering a pi from a 12v lead acid battery and today having analogue inputs and servos. Perhaps an explaining computers, robot or weather monitoring station would be a nice combination of the two episodes.
Thanks for this. I have a video on using servos with a standard Pi here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-xHDT4CwjUQE.html I also did two videos on a weather station using a Pi earlier this year, first one here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ChQpD2gsC20.html -- and second (where I build an anemometer) here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-1LPEPZ02-t8.html But there will be more projects . . .
It might be too much for RU-vid but, I'd love to see an explanation of a Pico (ideally a pair or n of them) hosting finite state machines interacting with a state machine on a host computer. In addition to or alternatively, having the Pico report state (ie. location, temp or the output of an "instrument") would be awesome. Really enjoy your series as do my son and grandson.
Great video on the Pi Pico... love the code and applications. Your old wire wound potentiometer is potentially causing the jitter in values... maybe time for a potential upgrade.
can not wait to see you with an update about the Pico W and its possibility accessing data from the lan or cloud like homeassistant. Usefull for showing the energy production of a solar power modul / generator live in Watts, kWh today, this week, month and year. e-Ink would be a nice solution too, also a forecast of the clouds / sun for the next 90 minuts a usual dish washer or washing machine or dryer does need to run on solar power. It is just an indicator using less power on an e-ink and is always useable for everyone in the household instead of using the phone and app you need to start or even log in. Just looking at an e-ink while you go buy is a lot better than the app overhead we usually see nowadays.
This is awesome. Now I just need to figure out how to use an SBUS RX with the Pico , and use an PCA9685 for the servos which will allow me to finish a couple projects I have wanted to do.
Very interesting projects, Maybe we can reduce shaking of the servo programmatically by not using the full resolution of the ADC value, I mean the full resolution 8200 - 1350 = 6850 What if we divide the value variable by 4 for example, get discard the decimal places then multiply it by 4 again, this way we'll get the same value range but in lower resolution which may reduce the shaking (I think) Thanks Chris, I hope we see more projects like this on Pico
Unfortunately the noise is much greater than 4. Just watching (trying to) the printed _value_ I saw a range of 6167 to 6253 a difference of 86. And that is just what I saw over that small sample at that exact point and it may get much bigger at different levels also. Now simply dividing by 86 would give about 80 steps in that 180° range which depending on the application may be enough resolution. But really you would need to reduce that by 2x to 40 steps as you would still get single jumps between those steps. See my earlier post about where the noise is likely coming from. A resolution reduction as you suggest is still part of the solution but there is more to it IMHO.
@@ElmerFuddGun Good point, I just read your previous comment, I'm not into electronics but it sounds logical to me, If the jitter comes from the ADC as you mentioned then I think finding a solution is a must, at least to reduce it to an acceptable degree
