7 Segment Displays & Arduino the EASY way! with MAX7219 Driver

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I've got a project I'm working on where I need to drive a ton of 7 Segment displays, so instead of dealing with all of the multiplexing myself, like I normally would, I decided to take the easy route and go with a dedicated LED driver (MAX7219). It runs the whole show and I'll explain how to work with it in this video.
Datasheet: datasheets.maximintegrated.co...
The other way I've done it explained here: • 7 Segment Display Mult...
The CODE is here: www.kevindarrah.com/download/a...
Wiki for the 328 Board: www.kevindarrah.com/wiki/index...
Check out my Tindie store (trigBoard is available) www.tindie.com/stores/kdcircu...
Thanks to all the Patrons for dropping a few bucks in the tip jar to help make these videos happen!
/ kdarrah
Twitter: / kdcircuits
For inquiries or design services:
www.kdcircuits.com

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17 июл 2024

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Комментарии : 60

@0shoulders0 6 лет назад

Thanks Kevin well explained video. Walking through the data sheet was useful. I down loaded the sketch, so now I have the building block of the program that I can alter to suit the project I'am working. And thanks Daniel previous comments, the red insulating tape really improves the display.

@iceberg789 7 лет назад

awesome, these are the types of tutorial videos that make the day ! MAX7219 is a nice chip to start spi programming as well.

@Kevindarrah 7 лет назад

yay! glad to hear it. Never sure if anyone cares about these part-specific videos

@Gr3ap3r78 4 года назад

Thank you for this! Awesome... exactly what I needed. Great work.

@AtomkeySinclair 7 лет назад

Excellent breakdown. Thank you for the time you took for the instruction. Well done.

@snailer06 7 лет назад

Kevin, Thanks for doing these vids! I thought I knew a lot about Arduino until I started watching your channel. What capture software do you use to record what's on the screen?

@ColinRichardson 7 лет назад

Thank you for your explanation of the No-op usage. that made things very clear.

@Kevindarrah 7 лет назад

lol, or I hope I didn't confuse you too much! I watched that part back again... face palm

@ColinRichardson 7 лет назад

Kevin Darrah to be fair, I was originally annoyed (at the spec) that the first digit was 0x01 as I am used to counting from zero. I was thinking "what was the point of a No-op". Then you explained. Made perfect sense. (to me)

@Kevindarrah 7 лет назад

ha, that's funny, because when I first wrote the test code - everything was for(int i=0... I have the same habit

@SeltsamerAttraktor 7 лет назад

I wrote my own library for this chip to display signed numbers, hexadecimals, octals, floats and even strings. The internal decoder is neat for simple things but ultimately a little limited.

@finster101 7 лет назад

Great video, very informative. So how many 7 segment displays can one chip handle?

@Martulas1000 7 лет назад

Do 14 segment 6 digits display pls. Keep up the good work

@rossanderson78 6 лет назад

Very informative. I like the way you explained it. I have the 7219 display and I want to use it as a clock with the DS1307 RTC module but I ran into a problem. I have the appropriate libraries installed but when I open the IDE it doesn't see the DS1307RTC and therefore its not included in the code. How can I solve this problem? Also I'm stumped as to why, after uploading the sketch I get a 'was not declared in this scope' error message. Please, any help would be greatly appreciated.

@artesalve3233 4 года назад

Hi Kevin, great tutorial! Since the popular LedControl.h library is everywhere in videos and tutorials and it doesn't take advantage of hardware SPI, understanding how this works with real SPI is really nice. I have a cuestion... I've made a custom 8 seven segments display and the wiring I did is not the same as the max7219 module you have, since mine it's not the same address of the hex values of the datasheet. I can not take advantage of that. How could I solve this?

@batticha462 5 лет назад

I can't run this sketch on arduino uno ! I used pin 13 as CLK, pin 11 as DIN and pin 10/2 as CS what changes in your sketch I have to do ?

@MrBajaJunky 7 лет назад

So would you recommend those for building an 8x8x8 rgb led cube?

@tpesposito 6 лет назад

I'm trying to get this to work but I can't figure out what data clock and load pin to plug my display into

@SanchezOKelly 4 года назад

If you wanted to daisy chain a few, and then power them separately from the arduino pin, how would you go about it?

@DupczacyBawol 7 лет назад

Sir, where do you buy your project boards at?

@BrentBlueAllen 7 лет назад

I've used the AMS AS1115 for driving 7-segment displays. The bonus there is that, on top of driving 8 7-segment displays, you can also scan 16 buttons/switches over I2C!

@Kevindarrah 7 лет назад

oh boy, I think I have to buy that part now...

@unknownhuman1000 5 лет назад

And it has an interrupt pin.

@raffaeledantonio7592 5 лет назад

many thanks from Italy. I was working on a project and I was going crazy. three max 7219 in cascade, only by chance did I notice those capacitors at the entrance and I solved, now all 24 digits light up

@paulc7798 2 месяца назад

Hello. I would like to have a 3 digit display but without all the wires. Could I use something like this? Thanks.

@Gringo_In_Chile 7 лет назад

Hi Kevin, Did you ever mention in this vid why you had to add the 100uf cap across VCC & GND? Or did I miss that? Thanks, Ken

@unknownhuman1000 5 лет назад

He did. He had problems with the on-board decoupling capacitor not doing a good enough job.

@rccanuck4473 5 лет назад

want to use this as a counter using a push button to increase the numbers and another for reset. Can you send a sketch for this ?

@emcgon 7 лет назад

There is an Arduino library called LEDControl available specifically for driving the MAX7219/7221 (playground.arduino.cc/Main/LedControl). That makes things even easier.

@Kevindarrah 7 лет назад

thanks, I knew someone had a library

@agr00m 7 лет назад

Works great for 7-segment displays, but is incredibly slow if you're using the MAX7219 for driving an 8x8 LED matrix. Especially if daisy chaining more than 3-4.

@UpcycleElectronics 7 лет назад

So essentially the MAX7219 can multiplex 64 LEDs? 8×8x8=512...÷64=8 of these IC drivers for single color LEDs. So the benefit is just the SPI interface? I'm curious if you could use the 7219 to interface with different ADC channels simultaneously as a metered display output. Something like a lab power supply that can display, current, voltage, average power, elapsed time, etc. from a single microcontroller.

@Kevindarrah 7 лет назад

yep, 64 LEDs. a lab power supply would be a perfect application of this part

@UpcycleElectronics 7 лет назад

Kevin Darrah Now I wonder if it would be possible to use the ST Micro STM8S003 microcontroller used on the eBay cheapo 3 digit voltmeters selling for less than $1. The STM8's have a 5 channel (multiplexed) 10 bit ADC and SPI. I haven't built anything with several layers of depth and a microcontroller before. How do I determine how many displays the microcontroller can multiplex? The MC will need to read the ADC values, and then output that information through SPI to daisy chained displays, and still keep up the persistence of vision illusion... I know it's a big question. I'm not asking you to solve the application. I'm looking for a theoretical frame of reference. What are the correct first order questions/answers to look for in order to find the solution to this problem? Datasheet link below if needed. www.google.com/url?sa=t&source=web&cd=2&ved=0ahUKEwidy7fnoazSAhWGRyYKHf9DBZsQFggdMAE&url=www.st.com/resource/en/datasheet/stm8s003k3.pdf&usg=AFQjCNHbWzXUQHBMe_BrsQXIbWn0JkDjeg&sig2=6nQ21tp4BjPT8DCfi9GfYQ

@peterstorm_io 6 лет назад

Can you easily make a 6 digit display out of this?

@JamesCoyle95 7 лет назад

Do you have any videos on designing a custom Arduino based board yet?

@Kevindarrah 7 лет назад

closest thing I think I'v got is just what I did with that 328 board - schematic is up there: www.kevindarrah.com/wiki/index.php?title=328Board

@JamesCoyle95 7 лет назад

Kevin Darrah You keep mentioning/using that board and it's kinda inspiring me to make my own board with onboard LiPo circuitry and some WS2812s. I've done a couple of projects that use a Nano or Pro Mini, a cheap LiPo board, and a WS2812 ring and figured it would be pretty nice if I had everything already on a single, 45mm diameter, round PCB. My background is in programming and computer science and I've really just jumped into electronics with no training so it's a little daunting tackling some of these projects not entirely knowing what I'm doing. I have just designed and assembled a custom mechanical keyboard that uses a standard Arduino compatible board as a driver which was my first big step into PCB design and I'm now looking to expand my skillset and be able to incorporate a microcontroller into my designs rather than sticking to an existing one.

@davey2k12 6 лет назад

why invalid library ?

@swooosh83 4 года назад

Would you have to shut it down prior to cutting the power?

@MahBor 6 месяцев назад

@rossanderson78 6 лет назад

BTW...I'm using the Arduino Uno.

@BreakingYTown 7 лет назад

I was using the max7219's to make a 8x8x8 led cube...then I came across the ws281x

@GeorgeGraves 7 лет назад

Great chip. Most of them on ebay are clones/counterfeit - but they work great. The real chip is like $6 IIRC. It is one of the parts that Maxim will send you for free as a sample.

@Kevindarrah 7 лет назад

yea, I'm with you on that. No way they're getting these for that cheap

@saintpine 6 лет назад

3:00 "you can daisy chain these up", it's NOT that easy. there is a design flaw. The module you have is the exact the one I'm using in this moment, I have just finished daisy chaining 5 of them. Unfortunately there is a design error in the module you are showing, the Vcc OUT is connected AFTER D1, in other words, the first module with work on Vcc -- Voltage drop over D1 ie: 4.3V, the second will work at 4.3V minus Voltage drop over D1 = 3.4V, the next module will work in an unpredictable manor working under 2.7V. The solution is to de-solder the D1 and jumper the pads. or the solution I prefer, solder a pin on the via that is near the diode (you can see the Pcb track going from diode to the via. and place the Vcc power connection on this pin. DO NOT connect each module directly to 5V leaving the diode in place, because the chip will work at 4.3V and supply the logic level to the next module that requires the logic in a 5V range.

@Majromax 7 лет назад

Why the apparent device resets at 14:03 and 15:22 in the video? Was there some weirdness about the programmer?

@Kevindarrah 7 лет назад

not sure - I've been messing around with the IDE under the hood lately... part of it was because of my troubles in programming the ESP8266. I'm working on cleaning all of that up - may actually do a video on that as well

@MatthewHartsuch 7 лет назад

Good content! I just ordered one of these $1.22 w/ shipping. Could be a good way to keep track of your RU-vid subscribers...

@Kevindarrah 7 лет назад

lol, that's actually what that blue display is doing. Uses the ESP8266 to get the subs and views... weather too. Part2 in the series: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-qU76yWHeQuw.html

@davoodzarei695 Год назад

♥️👍

@edgeeffect 5 лет назад

Thanks @Kevin Darrah.... you've answered my unanswered question on Electronics Stackexchange electronics.stackexchange.com/questions/412986/max7221-not-always-powering-on/417167