Controlling Mechanical 7-Segment Displays?! How RS-485 and UART works! || EB#43

Visit flipdots.com/en/products-serv... to get your own mechanical 7-segment displays! (flip-digits.com/)
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In this video I will be having a closer look at commercial mechanical 7-segment displays and find out how they work. Afterwards I will be creating a KZbin subscriber counter with them and an ESP8266 by not only finding out how the control PCB for the display works, but also by learning about the RS-485 and UART interface. Let's get started!
Thanks to Alfazeta (flipdots.com) for sponsoring this video!
Music:
2011 Lookalike by Bartlebeats

[@pauljackson2126]

That sound of listening to mechanical clicks of these displays and even hearing the clicks of relay array is always a pleasure to hear🙌

[@sarmadrafique4472]

More like a therapy.

[@joinedupjon]

Yep I'd be looking for excuses to add needless extra segment flips just to make it click - non numeric spinning wheel effects etc.

[@reggiep75]

Poly-rhythmic relay click patterns are enjoyable to hear.

[@bexpi7100]

if you want to see some mechanical display + relay awesomeness, proto g engineering made a cool thing: kzbin.info/www/bejne/qZyQkK2wpNuAfbs

[@MrQuanticox]

here is more: kzbin.info/www/bejne/qZyQkK2wpNuAfbs

[@sikkepossu]

He's getting more and more insane with that "I will see you next time" thing. :D

[@ArnaudMEURET]

Those punchlines gimmicks are usually the last straw that pushes me to unsubscribe when a channel’s content gets repeatedly disappointing... Not that it has been the case yet with GreatScott but I still would love if he got rid of that annoyance ! 🤯

[@PassiveDissimulation]

Arnaud MEURET I think it’s funny! At least it isn’t the same every time. It’s his catch phrase.

[@josephhacker6508]

This video isn't sponsored by JLC-PCB

[@Rainbow__cookie]

Reality is often disappointing

[@labiadh_chokri]

This video is sponsored by ALFAZETA

[@josephhacker6508]

@@labiadh_chokri It doesn't have the same ring to it.

[@hardikmonga]

Boring without JLCPCB commercial 😂

[@anonymouspuppy]

Hardik Monga I know

[@lemonglataitor2123]

How to stress out children taking a timed exam.

[@greatscottlab]

Haha true :-)

[@AnthonyGoodley]

Lol that's funny.

[@girishradhakrishnan2699]

Lol

[@Glasshopper]

Very funny 😂

[@rich1051414]

Gradually increase the volume, but slow enough to make the kids think they are going insane :) This is why I am not a teacher... the kids would need professional help after my class.

[@ZevHoover]

I can’t be the only one who starts twitching slightly every time he runs the highlighter over the black pen enough times that the black ink starts to run. Love your videos though man.

[@glennlawrie-smith8570]

Zev Hoover Yup.

[@glennlawrie-smith8570]

Zev Hoover Yup.

[@DarkThanosGr]

I scream NOOOO every time!

[@TheInCaver]

True!

[@gglovato]

ajjaja me too

[@Nathan0A]

I don't know why, but the highlighter smearing your ink really bothers me on some fundamental level. Great video though!

[@martincerny3294]

He does this on every video, it's triggering lol!

[@izzieb]

These kind of displays always remind me of the old clocks and departure boards in Britain, under British Rail.

[@CTCTraining1]

Yes, I wonder which rail enthusiasts managed to nab them. They used to make very solid clonking noises indeed.

[@izzieb]

@@CTCTraining1 I'm sure many did. I have fond memories of the old boards at places like London Bridge, making the distinct sound as the boards updated.

[@SheeplessNW6]

@@izzieb those departure boards are called 'split-flap' or 'Solari' displays, and there are at least a couple of companies who will sell you a new one. Well, I'm not sure whether Vestaboard ever stopped being vapourware, but Oat Foundry are certainly shipping. If you google for 'split-flap display' you'll find various hobbyists who have made their own!

[@samuell.foxton4177]

The station clocks in the UK were these, not split flaps

[@PabloAymerich]

And to get a price you have to ask for a quote. :( why couldn't they put at least an MSRP or estimated price per digit? It would be good for them to offer a DEV kit for $XX dollars with 4 digits and uart board?

[@sarkybugger5009]

_If you have to ask, you can't afford it_ is the usual approach of companies like that. Screw them! They must be out of patent, so I'm sure there's a factory in China churning them out by the thousand, for a dollar or two a piece.

[@PabloAymerich]

SarkyBugger I felt that way exactly

[@StephenHoldaway]

Search for "ebay Ferranti Packard" on Google - I found it slightly cheaper to buy new-old-stock or used original displays. Alfa Zeta is manufacturing new stock of an existing design which is great for industrial customers, but for hobbyists the supply chain aspect doesn't matter. When I got a quote from Alfa Zeta in 2018, it was cheaper per unit to buy a dozen on ebay including shipping than to buy 500 new units.

[@hackerman7835]

to quote another comment: The pricelist i got when ive asked was 9 Euro for a 7 Segment without controller (as shown in the beginning) 24 Euro for a single digit controller (didnt ask for code to controlle it, wanted to use it as a base for my own design). And the Simple flipdots were from 4-12 Euro available. Just mail them, the reply was fast and informative when i asked some questions reguarding shipping and price. Hope this helps. Their page also shows some cool Projects they did with artists.

[@beware_the_moose]

@@hackerman7835 at those prices why don't they just put a PayPal button on or something! I'd buy!

[@davidadams421]

Absolutely brilliant - glued to the screen! Your patience and commitment is inspiring.

[@hackerman7835]

PRICING FOR OCTOBER 2019: 7 seg modules: 9 EUR apiece for 1-99 pcs controllers: 21 EUR for 1-99 pcs 190 EUR for a bundle of 1x10 digits with controllers

[@marcinpkrysinski]

hackerman 7 Seg is 6.50 EUR for any qty...

[@marcinpkrysinski]

Solitary Midnight for limited time they sell any qty for 1000+ price which is 6.50 EUR

[@dwild92]

@@marcinpkrysinski any quantity 1000+.... Yeah that's not any quantity if it's over a quantity.....

[@jagadishk4513]

Hi Scott, I am debugging an RS485 design-driven by raspberry pi, before coming to this video I was tired upset because it was not working and it was 3AM in the morning. In your video you mentioned that the baud rate must to matched, then it dawned upon me that I must modify it and it worked. I guess when your frustrated you mess up even the most trivial things. Your video gave my cluttered mind a hint. Thanks a Ton, Scott, never stop making these videos.

[@MrJuuustin28532]

You are THE BEST at this out right now. Thanks for all your work. Awesome! 👍

[@cabasse_music]

your vids are the best, man. can't believe i hadn't found your channel sooner

[@alanm.17]

This could’ve made a really bad ass 80s dashboard speedometer

[@stevenmorisset4307]

10 digits will never be enough for you GreatScott !

[@graphenepixel8231]

Billions of subscribers

[@GRBtutorials]

Yeah, when the human population reaches 10 000 million, he will need an extra digit. Until then, it’ll be good enough.

[@rafaswierczynski]

So cool those displays :) As always - nice video! And sound of switching.... lovly...

[@vectorchan5647]

Hopefully china starts making these. I'm not buying from a company that won't tell you the price without "getting in touch with a representative"

[@g00st62]

Thats basicly just another way to say "way to expensive for you and dont even try to buy them if you dont need at least 5000"

[@hackerman7835]

someone ITT commented the following: Just contect their [e-mail] email address. The pricelist i got when ive asked was 9 Euro for a 7 Segment without controller (as shown in the beginning) 24 Euro for a single digit controller (didnt ask for code to controlle it, wanted to use it as a base for my own design). And the Simple flipdots were from 4-12 Euro available. Just mail them, the reply was fast and informative when i asked some questions reguarding shipping and price. Hope this helps. Their page also shows some cool Projects they did with artists.

[@doublebulbing]

@@hackerman7835 they are cool but too pricey just to buy to play with

[@geomagpsz]

I'm afraid that most of the times it works this way with industrial products :/ every time I have to do research to purchase components for a project is the same, I have to send s thousand emails asking for quotes (Usually they answer back with a huge price xD)

[@lptf5441]

I really want to commend you on a particular detail of your videos... the time and effort you take, as a non-native English speaker, to slowly and clearly pronounce each and every word in your video. So many videos from people who are non-native speakers of languages are almost unwatchable because of how difficult it is to understand what they are saying. They have poor pronunciation, they mumble, and they speak way too quickly. It can be hard enough for some native English speakers to understand other native English speakers from different countries, but non-native speakers are other level of difficulty. However your efforts are absolutely wonderful. All your videos are very easy to understand. Thank you for making the effort.

[@wtf6892]

Thank you for making this kind of videos it's priceless!

[@derekchristenson5711]

Neato! Thanks for showing this in action.

[@dieterdodel5265]

Machst Sehr gute Videos. Einfach erklärt. Gefällt mir sehr💪🏽

[@StreuPfeffer]

Ive found the company a while ago through another YT vid. got myself a couple 7 Segments and some flipdots. Also got a single RS485 segement, didn't get to them unfortunatly yet. Thanks for makeing it more clear how they are driven though.

[@MrKugelkopf]

How much did you pay for it? And is there a shop?

[@felixwurm1467]

i think you have to contact them

[@StreuPfeffer]

@@MrKugelkopf Just contect their [e-mail] email address. The pricelist i got when ive asked was 9 Euro for a 7 Segment without controller (as shown in the beginning) 24 Euro for a single digit controller (didnt ask for code to controlle it, wanted to use it as a base for my own design). And the Simple flipdots were from 4-12 Euro available. Just mail them, the reply was fast and informative when i asked some questions reguarding shipping and price. Hope this helps. Their page also shows some cool Projects they did with artists.

[@MrKugelkopf]

@@StreuPfeffer thank you!

[@kirbymia6209]

This is pretty interesting especially since we just started messing with USART for our microprocessors course. I might make one of these some time.

[@alpagutsencer]

The soul of the Marco Reps is in us.

[@engineer0239]

Funny. I worked with Modbus Commands sent from a PC that got converted to RS-485 in my holyday job. I was controlling an Axis that moved a camera for Image recognition. I was coding an UI for it and now you´re making a video about it. Nice.

[@MikeysLab]

Love this display, but the companies site does not have pricing or a way to order :( would love to use these in a project on my channel.

[@anycatdessai]

Liked the new fusion way of project and electronics basics video in one. Makes it quite interesting.

[@greatscottlab]

Thanks for the feedback :-)

[@srinivasraor770]

That was amazing project you took scoot i just loved it.

[@andrewkieran8942]

Another great topic, but I missed something. In one of the the diagrams, one end of all of the magnets in a digit are connected to a common source, and the individual segments are grounded by a darlington transistor pair. How do you switch between the two states; segment displayed or segment not displayed? Removing the power retains the existing state so don't you need to apply the power for state 0 and reverse the polarity to select state 1? How do reverse the polarity in this case without an h-bridge?

[@raykent3211]

Me too. I guess he used Darlington pairs to drive leds that needed more current than an ordinary logic chip can provide and he guessed that this was done here. But, as you imply, current can only be passed in one direction through a darlington pair and the muxing won't work. Most likely there's a number of mosfet H-bridges involved. There's a lot of chips on that driver board!

[@valshaped]

You might be able to get away with pulling the common line high and pulling only the electromagnet you want to load low? I'm not sure.

[@danielvalle3789]

Pondered the same thing! Figured I missed something (which, I obviously did but still happy I'm not the only one lolol.)

[@pjshots]

I need those things in my life! So functional and direct.

[@jamest.5001]

Kinda cool retro style tech, reminds me of the old alarm clocks!!

[@sereisethchhay7716]

Very Nice. Also your explanation lead me to understanding another things as well. Thanks.

[@Gamezone-sd3er]

Well I can use it as notification for great Scott video upload

[@greatscottlab]

Correct :-)

[@thexpto51]

Very good! Really Nice Work! Congratulations!

[@otm646]

We use a large 3 inch set of mechanical displays on our racing sailboat for important data. It's excellent, low power and most importantly doesn't have the visibility issues like LCDs with polarized sunglasses. Old tech but still the best in some applications.

[@diyexplorer8728]

I want to use this as a clock on a school library. Great video!

[@tushar673353]

you did really lots of work on this project

[@rif6876]

Curious, how many attempts did it take before working properly. And do you remember the mechanical display that flips through the numbers? Also a very satisfying sound

[@graphenepixel8231]

I love that sound.

[@easyelectronics4364]

one of the awesome videos i have ever seen!!! :)

[@crazyivan030983]

And now you have red "black" highlighter... :) super video :) greetings from Poland :)

[@Miata822]

OK, that's pretty cool. It just seems to me these displays call out for an analog driver. Thinking about how to do that.

[@giotinez5996]

I learn a lot with ur videos even many of them are for avanced dudes. Thanks brother

[@Gideon_Judges6]

This is some heavy artillery compared to just a 4511 or similar 7 segment decoder, but then again you would need multiple (10x) plus some kind of transistor as I suspect those coils draw more current than the typical LED seven segment.

[@graphenepixel8231]

I thought the same thing.

[@manitoba-op4jx]

SirBudrick they probably require a quick and rather insignificant pulse of current to toggle like most electromechanical displays of its type

[@andymouse]

I must say, those displays are quite charming.

[@AmeshaSpentaArmaiti]

They look really nice

[@lukaszpodgorski]

Great Video Great Scott

[@keithking1985]

I have to say it is satisfying to look at.

[@jerometv7637]

Thanks! great video, now you made me want to have those mechnical displays too ;)

[@surajsingh4477]

nice video teacher, always waiting for next, keep up, thanks

[@Clark-Mills]

First saw the display and thought... I could optimise that code by storing (buffering) the state of every segment and then just flipping the segments that have changed. Then I look at 4:06 and realise that the code is already optimised. Nice.

[@ZeroMass]

Another interesting video. I look forward to your uploads 😋🍺

[@greatscottlab]

Thanks :-)

[@djaberkharoubi3825]

Very Great explanation, thank you so much :)

[@IvegaEletrônica]

Muito legal esses displays.

[@sumantacm1]

Nice video Scott but I was more interested in large size led seven segments... I am miopic and was planning to build a large size digital clock so even in the middle of the night I can see time without searching for my glasses first... Can you please suggest me where I can get those...

[@dr_stoned_4207]

Finally a new sponsore!!!!!!!!!

[@junuhunuproductions]

Amazing Video as always :)

[@labiadh_chokri]

Hi nice display did you know how many cycle will last , and can you make a circuit to read the state of the display like old Magnetic-core memory

[@justinsnyder5260]

Hey great scott, I would love your help with creating a DC voltmeter with bluetooth that sends its readings to a raspberry bi or arduino.

[@DIYPINOY]

Great project. Great scott

[@charlescothran4946]

This video is fantastic!!!

[@ats89117]

It's a good thing they sent you a 10 digit display so that it can count up to ten billion subscribers. You never know!

[@Jacobsonro]

Very nice video, do you know if these could be used with a openEvse?

[@bharathr2871]

More than college education your channel gives me more information.

[@paulturner5769]

That doesn't explain how the drivers supply reverse voltage / current to the segments you want to turn from ON to OFF though.

[@popcorny007]

Presumably that is handled by the controller board. He is just programming to get a serial output.

[@paulturner5769]

​@@popcorny007 I was referring to the explanation of turning segments ON at 2:58 to 4:03, It is NOT like multiplexing LEDS which turn OFF when there is no power, these segments retain their state until power is applied in reverse.

[@labiadh_chokri]

Yes every segment must have a H bridge or be connected between tow Logic output that can source and sink the appropriate current .

[@ash0787]

Your videos have been very useful for me GS so i'm gonna tell you about a problem / project i've been working on... since I started studying electronics a year ago i've wanted to reverse engineer a mobility scooter / electric vehicle ESC, its a DC brush motor which is controlled by a single potentiometer which controls reverse, forward and braking, the trigger seems to act as a desired % of maximum speed, and the vehicle automatically accelerates or brakes to meet that % target. The boards seem to utilize a microcontroller, I would like to implement a similar system without. Firstly I am trying to make it so there are 2 pedals, brake and accel which will each give a 0 to 5v signal lets say, this is then compared to see which one is higher, which activates either braking or accel mode.... there will be two 555 timers creating the duty cycle for power or regen braking seperately depending on the pedal signal intensity. The issue im struggling with right now is trying to control the PWM duty cycle of 555 timer using just a single 0 to 5v voltage ( not a potentiometer ). My idea is to use MOSFETs to control the resistance of the charge / discharge portions of the 555 timer operation, but im having trouble fine tuning it so that the mosfet works properly as a variable resister, I have to compress the voltage into a confined range of about 2v to 3.6v it seems.

[@yeahitworks]

Love these mechanical display... I'm working on a project that needs a bigger display, 10" - 12" height. Any recommendations?

[@d23rfd3gfjhjhgfdze]

This channel should have more Subs.

[@theteenageengineer]

The control board seems a lot like a DMX controller for entertainment industry lighting, big Clive has some great videos explaining it. But DMX uses RS-485 to be able to control up to 512 lights and the 2 RJ-11 ports on the controller board is where I got this connection from because for DMX there is always 2 ports on each light so you can connect multiple in a chain.

[@haroonsyedmohammed8430]

Your videos will be exciting!

[@mathiasbackof4993]

Oh man finally a real thumbnail

[@mgfails9274]

What components do you usually buy like in the facebook post "refilling the bins". I am really curios because i want to buy components from Aliexpress. In my city an IRLZ44N is 1.8€

[@d942yd42]

Your source circuit and darlington sink cannot reverse polarity of the magnets ?

[@rudebwoyway]

Are you planning on putting it in an enclosure and having it run constantly?

[@cquiles386]

I hope you make a video of you making a custom enclosure for this!

[@sinfulf4i]

ohhh that was soo cool need a clock made like that with the secs displace clicking away

[@therealcherti]

Great, now I have to get myself some of those :D

[@legominimovieproductions]

i got a electrical meter with rs485 output and 2 rs485 to ttl converters, but i cant figure the code for the mega 2560 or nanos out

[@dj_paultuk7052]

RS485 used to be really handy in the pre-wifi days as you can run it really long distances with no loss of signal with a data speed of 115k. A company called Lantronix also sell a Ethernet to RS45 server device (UDS10), so you can drive RS485 on a ethernet based network.

[@resneptacle]

Still being used in the show and theater industry for the DMX lighting protocol

[@blink11101]

This video was awesome!

[@vibhanshuchandwani4527]

Hey, what about your wind turbine that you posted on facebook

[@Enigma758]

With source driver common to all electromagnets, and sink driver to each segment, it's not clear how the coil polarity reverses in order to reset (darken) the segment.

[@stjepansavic4485]

That sound for mi is beautiful

[@startobytes]

Hello, can you make a sr latch with transistors ?!

[@unperrier5998]

The three digits on the right hand side (lsb) mechanically switch more often and hence will wear before the most significant digits. They must have thought of that and allo you to replace them or swap the 3-digit module with the msb one.

[@brane3698]

segments have no mechanical linkage, they are controlled with electromagnets, so there is nothing to wear out, at least not that soon...the manufacturer states segments are rated for over 250 million operations

[@unperrier5998]

@@brane3698 250 million operations, that's plenty but it's probably less due to dust and dirt.

[@unperrier5998]

@oH well,lord! if you prefer.

[@romandirscherl151]

Please Upload a Video in Twitter where i can hear the clicking sound It sounds so awesome

[@greatscottlab]

There already is one on twitter.

[@MCsCreations]

Really, really interesting! 😃

[@anikethdas98]

Can someone explain how the electromagnets keep their polarity without a power supply? Is there another magnet inside which gets flipped inside each of the coils?

[@mgfails9274]

Is the hantek dso 5202p is a good osciloscope chioce?

[@agarceran]

I personally preffer the look and sound of the Split-Flap displays, but this looks interesting and are quite a lot simple.

[@sudhanshushekhar6920]

That's nice display 👍👍👍👍👍

[@andrewhamop6665]

Are we going to see the subscriber counter in videos from now on? I think that would be an awesome idea!

[@KJ7BZC]

That is an awesome display, I think that there are even dot matrix displays like that. Just curious, is it possible to use a regular arduino with an Ethernet shield to monitor subscribers? Instead of using an esp8266 that is.

[@zaprodk]

Yes and Yes.

[@KJ7BZC]

@@zaprodk cool

[@movax20h]

Well. But how these ICs reverse also polarity of signals going to displays to turn segments off?

[@greatscottlab]

That is a good question. I assume it might have something to do with the tons of diodes soldered to the back of the electromagnets. Not sure though, I did not dig that deep.

[@pratikraghuwanshi5716]

Can you please make a dc current booster circuit , which boost 2amp of current to 10amp DC .

[@jcgo16]

The sound that it makes so.........gooooooodddd

[@tomshalom]

Hi. Can build an ammeter(ac) and voltage(ac) wireless . With arduino.

[@atti1120]

Why the \xFE before \x00 ? I have limited understanding, but isnt the port continously sending high when idle, and then begins when it encounters a low? So i get x00 but why the xFE? Best

[@anyfinity]

1:48 - 1:52 that's a great idea!

[@Timh-hx2le]

Yeah, a new Video!