#256

A quick look at my 3ft / 0.9m MAX7219 display controlled by the MD_Parola library.
► PCBWay $5 for 10 pieces www.pcbway.com
Much more (including the demo sketch) in my GitHub:
github.com/RalphBacon/256-MAX...
After 5 years I've started implementing the 3ft (0.9m) MAX7219 LED Matrix into my workshop! No rush! It's not complete yet but the library I'm using has a few nice tricks that are worth sharing, plus some caveats about the wiring of these longer displays.
Hardware
MAX7219 Dot Matrix Module 32x8: available in red, blue and green
s.click.aliexpress.com/e/_DeS...
Software
Marco Colli's (MajicDesigns) MD_Paraola library
github.com/MajicDesigns/MD_Pa...
If you like and use this library please consider making a small donation using PayPal (see the link in his GitHub page)
(And before you ask, of course I have donated! 👍)
More information (including all links, sketches & PDFs in my GitHub):
github.com/RalphBacon/256-MAX...
► List of all my videos
(Special thanks to Michael Kurt Vogel for compiling this)
bit.ly/KZbinVideoList-RalphB...
► If you like this video please give it a thumbs up, share it and if you're not already subscribed please consider doing so and joining me on my Arduinite (and other μControllers) journey
My channel, GitHub and blog are here:
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• / ralphbacon
• ralphbacon.blog
• github.com/RalphBacon
• buymeacoffee.com/ralphbacon
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My ABOUT page with email address: / ralphbacon

[@chrisfairbrother9197]

Good video Ralph. With regard to your day of the week dilemma, once you are retired, every day is a Saturday 😊

[@RalphBacon]

Saturday has a special feel, all to its self. But I now quite like the Monday feeling, new week, new beginning. Wednesday is good too, half way done but still some way to go. It's a weird thing. Maybe I'm just weird. 🙃

[@rodneysmith1750]

This is another great introduction to something I've wondered about (matrix displays) and a lead into what appears to be an excellent library, thanks again Ralph for your videos...

[@RalphBacon]

Glad it was helpful! Merry Xmas!

[@davidh8285]

Thanks again for another info packed video! I enjoy using these displays linked together, too. I usually buy them in multiples when they hit a good price. They come in a variety of colors, too. Like you, my projects sometimes get delayed for other things that need done. I built a scrolling marquee from a project I found on "instructables" web site. It is based on the D1 mini and these matrix panels. I kept meaning to get a piece of tinted lexan, acrylic, or plexiglass (whatever it's called) to put over the panels and just seemed to never get around to it. This summer I found a company in the U.S. called Tapp Plastics that will custom cut a wide variety of colored acrylic sheet for very reasonable prices, and ship it to you. I finally got a smoke colored panel and put it on my display. It made a huge difference in the look of the display. It hides all the little white dots where the led's are mounted and evenly diffuses the lit ones. The whole thing is much more readable now. I wish I had done it sooner! It is definitely worth the time and trouble to get a cover panel for these matrix displays. Holiday Cheers!

[@RalphBacon]

You've read my mind, David (or you have hacked my workshop webcam and saw me investigating this very topic yesterday). Yes, although I have affixed the long strip in my workshop (it's only a couple of screws) I do want to make it neater (ie properly enclosed) and, most importantly, an acrylic strip across the whole thing. I was thinking dark red (looks black until lit). I've found a UK firm to do this, my quest for the Xmas to New Year period!

[@gpTeacher]

Here's to more great Ralph Wisdom in 2033. Thanks loads!

[@RalphBacon]

More fumblings, errors and false starts, you mean Gord! Ha ha! Have a great festive break ☃️🎅🎄

[@gordanmilne7034]

We can't wait 10 years!

[@RalphBacon]

Hang on, what year is it next year?

[@TheUnofficialMaker]

@@RalphBacon better add the year to your display! ha ha

[@MrCatchers]

Hi Ralph, I must be getting on as I remember following and experimenting with you when you did your previous series on the MAX 7219. Wow, 5 years ago I didn’t know it was that long. I have some spares I bought at the time, so there may be enough to build this new long one. Thanks for all the videos and support this year. Have a great Christmas and a healthy happy New Year.

[@RalphBacon]

I'm impressed that you stayed with me for so long! What goes around comes around, I guess, although if I knew then what I know now... sigh! Yes, build it, it's fun. Mine is now installed but I do need to get on with the software.

[@Cptnbond]

Please have a good Christmas, Ralph, and I'm looking forward to your future projects next year. Cheers.

[@RalphBacon]

Thanks, you too!

[@gordondyer6310]

Thanks for sharing your experience. I have had 4 modules of 4x64 LEDs waiting for a year. Now I'll try to use them in the new year. Happy Christmas!

[@RalphBacon]

Perfect! My work here is done, Gordon!

[@keitholiver3981]

Merry Christmas and a happy new year Ralph, looking forward to new and exciting projects in 2023

[@RalphBacon]

Same to you! Nice to see you here, Keith 🎄

[@electronics.unmessed]

Thank you very much for the video, always good insights! Merry Christmas & Happy New Year!🌲🌲🌲 BR from Germany

[@RalphBacon]

Happy holidays! Und einen guten Rutsch!

[@romancharak3675]

I have started many projects that have been stashed away, in various states of completion/incompletion. So I totally empathize with your situation, Ralph. Merry Christmas to you and your family.

[@RalphBacon]

Thanks, Roman! I've actually installed this strip in my workshop now and can update it OTA if needed or via USB cable whilst I continue to work on it. Have a good one!

[@Friendroid]

Merry Christmas, Ralph. Thank you for the great content throughout these years.

[@RalphBacon]

Thank you very much, I'm very happy you find them useful 👍

[@simonwhite3137]

Can’t beat a good led project 😊 Merry Christmas Ralph!

[@RalphBacon]

Happy holidays! Nothing beats flashing lights, for sure!

[@markgreco1962]

Ho Ho Ho Ralph. Keep up the great work.

[@RalphBacon]

Thanks! Will do!

[@OtusAsio]

Have nice hollyday to you too...I made a clock with the four displays few years ago and it was very intersting, so with what you have shown us here it could become better...thank you!!!

[@RalphBacon]

Happy holidays! Yes, a rewrite of your clock could be interesting. The seconds (or minutes) could "slide" in from any direction, for example. A nice project.

[@steverileyretired]

Great Job, well done

[@RalphBacon]

Thank you very much! Appreciated. 🎄

[@followthetrawler]

Merry Christmas Ralph! Thanks for all the content this year

[@RalphBacon]

My pleasure! And a Merry Xmas to you too Stuart!

[@mrroobarb]

Thank you so much for your enlightening and informative videos Ralph. Merry Christmas and Happy New Year to you are your family! Best wishes, Bruce.

[@RalphBacon]

Same to you! I'm happy you like the videos, my time here is not being wasted! Have a great one.

[@Chriva]

Welcome BACK Mr. Bacon :)

[@RalphBacon]

And I'll be BACK next year!

[@scottstevens7569]

Happy Holidays Ralph! MAX7219 is a cool IC and with those libraries you are doing some nice, usefull stuff. Making things like this wifi enabled exponentially raises the usefulness. Just yesterday received 10 chips to solder into things partly built sitting on a shelf waiting for....'that reason to finish".... Using strips of 2812b leds I've created a 1.1m x .2m array for larger message displays, but the software/code doesn't always perform the same as with those matrix squares, again-just another path; plus all my first iterations were static Arduino code/libraries vs making them ESP32 or Wifi controlable is that same hang-up -: "I have to recode alll this...." so, hint/hint I'm looking forward to your next upcomming video of Android App creation for ESP32 wifi matrix control ;) 🎄😄

[@RalphBacon]

I'm glad I'm not the only one who procrastinates... er, waits for the R&D phase to be fully finished before committing to design! Yes, I will show all once it's done.

[@flashcorp76]

Thanx, been waiting for something like this😊And Joyeux Noël as well 😉!

[@RalphBacon]

You're welcome 😊 See you in 2023.

[@noweare1]

That's a good use of these leds. Happy Holidays, Ralph.

[@RalphBacon]

Same to you! Yes, I'm just super happy I've _finally_ got round to doing this. No rush! 🤔

[@ShishakliAus]

Merry Christmas Ralph!

[@RalphBacon]

And to you too! 🎅🎄☃️

[@Ivor_Nastyboil]

Have a good Xmas Ralph.

[@RalphBacon]

Thanks, "Ivor", you too!

[@daveharris3384]

Thanks Ralph and a Merry Christmas to you,. Partial retirement means my Wednesday is my new Friday!

[@RalphBacon]

Happy holidays! Partial Retirement, hey? I think that's about as good as it gets, Dave, you never really, truly _fully_ retire. Well, OK, one day we do but not while we draw breath! Have a great (partial) retirement!

[@andymouse]

Hi Ralph, Merry Christmas to you and your's !....cheers.

[@RalphBacon]

Happy holidays! Great to see you here, Andy!

[@dazryan3463]

Merry Christmas Ralph

[@RalphBacon]

You too Daz!

[@ianbertenshaw4350]

Merry Christmas Ralph! Thanks for the awesome videos this year - I have learned a lot from them and your channel is one of the very few that try to teach us to write better code, many just concentrate on the project and breeze through the code or just steal someone else's code and hack it.

[@RalphBacon]

Merry Christmas to you too, Ian. Thank you for your supportive words, makes it worth my while to do! Have a good one and see you in 2023. 🎄

[@fiqianarofi2991]

Mery Christmast Mr ralp💡

[@RalphBacon]

Indeed, Merry Christmas to you do!

[@IanSlothieRolfe]

Hope you have a great Christmas Roger! This is a well timed video, as I bought a cheap 5 module LED array in the summer and was thinking about doing something with it (not as ambitious as your notice board!). You've been making some top content lately, and very different to other channels so well done, I know you've also had a lot to deal with outside the channel recently too.

[@RalphBacon]

Thanks, you too, Pete, er, sorry, Ian.😁 These modules are pretty cheap (let's say inexpensive, sounds better) so you can extend your strip or even have a double height array! Have fun!

[@IanSlothieRolfe]

@@RalphBacon Oops Don't knpw how I got that wrong.... sorry! I'll be doing lines Bart Simpson style.....

[@TheEmbeddedHobbyist]

The nice bit about this chip is it can also drive 8 7-segment displays. just looking at the LP5860 11 × 18 LED Matrix Driver With 8-bit Analog and 8-/16-Bit PWM Dimming. Now just got to see if TI will send me some samples to play with next year. plus the fun is in reading the datasheet and working out how to drive it. Merry Christmas and a happy new year.

[@RalphBacon]

Indeed, I did a couple of videos on that aspect as well. The 4-module unit is pretty cheap though, so if you don't get free samples that could be a source!

[@fredflintstone1]

Meowmass!!!!!!!!!!!!!!!!!!!!!!!!!

[@TheEmbeddedHobbyist]

@@fredflintstone1 Happy Woofmes Fred.

[@jstro-hobbytech]

Holy crap Ralph, you went bananas. Those boards are cheaper than the chips themselves now. They're very well built. They're currently on sale on aliexpress as well I believe.

[@RalphBacon]

Yes, I did go a bit mad but now it's installed in my workshop and it's _awesome_ !!! 🚥🚥🚥🚥🚥

[@jstro-hobbytech]

@@RalphBacon I definitely approve. I love leds

[@JohnJones-oy3md]

They're not genuine Maxim parts. The knock-off 7219's can tend to be glitchy and unreliable (confirmed by a very helpful engineer from Maxim support after lots of frustration in trying to get a project to work properly). Wouldn't ever use one for anything important.

[@mainer8912]

If you want to add a diffuser over these displays the best plastic I found is from an old flat panel TV. One of the layers of the screen is a semi transparent white plastic. Easy to cut to the size of the frame. It will hide everything except the lighted LED.

[@RalphBacon]

I'm still considering my options here, so thanks for this input. Keeping the frame slim but somehow secured is now occupying my thoughts!

[@BenMitro]

ATBFCATNY,YFAYVT,R. (All The Best For Christmas And The New Year, Your Family And Your Viewers Too, Ralph) I'm glad you have one foot in Australia.

[@RalphBacon]

HHTYAYB! Happy holidays to you and yours, Ben! 🎄🎅☃️ (no snow in Oz this time of year, of course). My daughter is having meals on the beach there!

[@RalphWLundvall]

Since multiple units don't just 'snap together', a short video on the construction of joining two (or more) together? It can be tricky unsoldering connectors that are not needed. We need all the help we can get.

[@RalphBacon]

They almost snap together. On one side (the exit, out) you solder a right angle pin _header_ (like I showed in the smaller, older unit). On the next module solder a right angle pin _socket_ like you find on an Arduino UNO board (but with fewer holes) to the _input_ connection. Then they just plug (push fit) together. They do need a bit of support though as the connection is not physically that strong. I screwed mine to a thin board. I've put some pictures of this on my GitHub here: (github.com/RalphBacon/256-MAX7219-Ultimate-Display )

[@MichaelBennett1]

The GitHub photo seems to show the pre-soldered header bent into the first unit, I tried doing it this way but ended up breaking the contact points when I repositioned it in a very tight space. You mentioned using a socket instead but I can’t seem to find a pin header socket with the correct pitch which is 1.27mm, do you have a link or even just the name of the connector that you used that I can search for?

[@delugeia]

Hello Mr. Bacon! I appreciate your videos and all of the details you include. I'm curious... where did you get your awesome breadboard?!?!

[@RalphBacon]

This was from a UK supplier, item AD11: bit.ly/3Crhdvo Not cheap but then again quality components never are.

[@PavolFilek]

Beautiful MATRIX to my rear ebike RED light, when I can display TEMP of the road and speed of incoming driver from radar.

[@RalphBacon]

Or a single 4x module at the rear as a brake light with some words too (eg flashing the words STOP, SLOW or TURN at the appropriate time). If I had the manufacturing skills I'd be a millionaire!

[@hopje01]

Merry Christmas, Ralph! Maybe alternate the personal messages with a scrolling RSS news feed?

[@RalphBacon]

Yes, I'm sure this will grow as time goes by.

[@WagonLoads]

I would like to know if it is possible to use a esp32 and MPU9250 to make a tilt/compass that can be used with a tablet that does not have a compass, so that the tablet can work with google sky map. I want to mount it on a telescope, so I can see what star I pointed the telescope at..

[@RalphBacon]

Hmm. You could certainly make a standalone compass that output coordinates, I'm sure. The tricky bit is interfacing it to your tablet, which I don't know how to do, sorry.

[@darrenchapman7203]

Wouldn't mind one myself connected to my google calendar and messaging services.

[@RalphBacon]

Go for it Darren, it's pretty easy to do with that library.

[@oldNavyJZ]

Any hints on what library should be used with an ESP32S3 & the MAX7219?

[@RalphBacon]

The same one that I am using in the demo sketch (should be in the GitHub for download). If not, ping me.

[@oldNavyJZ]

@@RalphBacon I got it to work great - had to specify FC16_HW and then was good to go. Thank you!

[@thisoldjeepcj5]

More than 2 of the four module displays is almost certain death for your voltage regulator, arduino, breadboard, etc. But even worse the 7219 chips fail to output data to the next section even if you catch it before you let the smoke out. Ask me how I know. Yes, I'm alumni of the School of Hard Knocks. With that in mind, if you beef up the wire size for + VCC should you not also do so to the Ground? Happy New Year to you, hope you had a Merry Christmas.

[@RalphBacon]

The current for the modules doesn't pass through the voltage regulator on the Arduino if you use the Vin pin (it then takes it directly from the USB input, assuming you are using USB and not some other voltage). Thus, your PC's USB cable or USB Hub powers the device, which is how I did it in this video. But you are correct that you do need to watch how you power such things. Especially when testing, then the likelihood that you will inadvertently cause ALL LEDs to light up (don't ask). Regarding the GND connection, that is of lesser concern as each module has a nice ground plane; but I did beef up the inter-module GND connections though with some additional solder.

[@spectrex1839]

I'm using these same displays. 1×8 (8x64). I've tried using esp8266 (nodemcu), arduino uno, wemos d1 mini. At first a few months ago all displays lit up while using the d1 mini. Now only 4 of the 8 light up. I've tested everything but I just can't get the last 4 to light.

[@RalphBacon]

If you apply a 1.4V @ 10mA (eg 5v with a 330Ω resistor in series) to each individual segment of the LED you can prove whether the hardware still works before blaming your code (that used to work just fine, you say).

[@spectrex1839]

@@RalphBacon thanks, I'll test this out.

[@thomasw2509]

Were you blinded by your displays being too bright? Did the overly bright display caused making Your eye injury? Consider replacing the Iset resistor on the FC-16 modules. Put on a 64k. This brings down the current per segment to app 10mA. It greatly reduces the overall current consumption and making heat. I have replaced the resistors on my 4 digit clock modules. It makes a huge difference. Way better to stand now having it runnning next to me.

[@tubeDude48]

Ralph, 1) is that a voltage translator in the center? 2) Have you made a board for the ESP32 yet?

[@RalphBacon]

Yes and no. No, really. YES: That is indeed a 4-channel voltage leveller in the centre as the ESP32 runs on 3v3 but the matrix definitely works MUCH better at 5v. And connecting a 3v3 ESP32 to a 5v peripheral CAN work (I had some problems) but it is safer and the right thing to do by adding a level shifter. Ultra cheap (it's only a few MOSFETs on a board) and ultra safe. NO: I have not yet designed a board for the ESP32 as I haven't fully designed the circuit. I want a motion detector so the display can dim (or turn off) when there is no movement as that means I'm probably not at my desk (or in my workshop). I'm also considering an LDR so I can dim (or brighten, more likely) the display during very bright days during the summer). I've found that level 0 (the dimmest setting) is still readable in a dimly lit workshop, and level 1 is plenty (which you saw). But in the summer I may have to up the max brightness. A couple of other things have crossed my mind, but no firm design as yet (not even which style of ESP32 board I'm going to use). Full details when I get it done (I may have some spare PCBs at that time to share around). In the meantime I'm leaving it hooked up on my breadboard just so I can continue the coding and upload OTA (or via the USB).

[@tubeDude48]

@@RalphBacon - Sounds good my friend!

[@mk6595]

Is there any difference between the red, blue, and green modules? They appear to be at different prices.

[@RalphBacon]

Yes, one has red LEDs, one has green LEDs and one has blue LEDs. 😁 Apart from that... red is more restful to the eyes IMHO. Blue is the worst for restfulness which is why blue light is blocked on phones at night. And red is always going to be cheapest as they are the cheapest type of LED. Exactly the opposite for blue LEDs and, of course, they are _cooler_ than other types, right 🤔? They also light up an entire bedroom at night if your TV manufacturer has used one. 😡 Merry Xmas!

[@mk6595]

@@RalphBacon Oh okay...I wasn't sure since the AliX pics didn't show the LED colors.

[@yogeshitaliya473]

🙏🙏🙏😅

[@RalphBacon]

Always good to see you here, Yogesh. Have a great festive holiday.

[@mitchellhw2006]

The quad display is oriented side ways (useless). I had to saw mine into sections and reorient them to get a horizontal display

[@RalphBacon]

OMG did you really say SAW them? You can buy others that are oriented the correct way (with the chip underneath the LEDs). But kudos to you that you did this!

[@fiqianarofi2991]

Greeting from Indonesia,.....nice tutorial,.....can i get your code?...👍

[@RalphBacon]

The code is in the GitHub for this video. Link to the GitHub is, as always, in the video description. Enjoy! (But remember the code was just thrown together for the demo).

[@jensschroder8214]

Einen guten rutsch ins neue Jahr. It's not even sure what "rutsch" means. Does it mean "glide over" ? Is that really a German word or does it come from the Hebrew? "Rosch ha schana tov", literally "a good head (beginning) of the year" Unfortunately, the destruction of Jewish culture in Germany has meant that we Germans no longer understand our own language in certain respects. Yiddish took over from German and some things were then found in the German language again. So have a good travel into the new year! Einen guten Rutsch ins neue Jahr!

[@RalphBacon]

I hear Rutsch to mean slip or slide (as on icy surfaces). I'll hang on tight as I slowly stumble into 2023! Thanks Jens!