7 segment display Pin outs?

Are you building a cockpit, planning to build one or just dreaming, this is your cockpit builder meeting point

Moderators: russ, Ralph

Message
Author
User avatar
jph
Posts: 2846
Joined: Fri Apr 10, 2020 12:50 pm
Location: Somewhere over the rainbow..

Re: 7 segment display Pin outs?

#181 Post by jph »

Hi Kirk,
Looking at the physical size and spacing of those display, it may be better to get some 6 dIgIt units AND pcbs
From Hispa as they are probably the exact same physical size ?

PCB -
https://hispapanels.com/tienda/en/41-pr ... uit-boards
These are the 6 digit display to a 20 pin IDC socket (fairly industry standard and the same format I use)
https://hispapanels.com/tienda/en/kits/ ... s-set.html

Their displays are -(probably) about the same size as the ones you have ?
set-of-6-7-segments-display.jpg
Check the actual measurements against yours.
I buy mine direct from the makers in China so can source them at around 20% of the price or less, but if you only need a few then this (hispa)is a good option.

If you watch the video you will see the way they link to the 20 way IDC.


As you can imagine it is easy to make the driver board FROM the 7219 with a 20 way IDC using simple protoboard - the one at the display end, it is probably worth buying the PCB.
Using IDC connectors the crimpers and connectors are also cheap. My set covers up to 60 way IDC - probably around 30 dollars for the complete kit for the crimp tools etc. The connectors and cable are really cheap. Really neat.
Again, if you look at all the professional sim products they virtually ALL use his method.

No professional sim hardware make that I know of connects directly to an Arduino or similar directly without output buffers and input protection etc. It is an area I believe AM needs to move into. But that's another story haha ;)
Joe.

You can call Manola at Hispapanels to discuss what you need in the way of displays,
I need to make another custom order soon from China for the actual display units so if there is anything special you need let me know and I will see if I can add it ?
Joe. CISSP, MSc.

Kaellis991
Posts: 581
Joined: Mon Sep 07, 2020 8:49 am

Re: 7 segment display Pin outs?

#182 Post by Kaellis991 »

Joe,

Those displays might work if I am reading this correctly. The displays I have are .2" (5.08mm) characters with a total length between centers of the 1st and 6th digit of around 35mm. It appears that at 33mm in length those are not any longer than what I was planning on using but about 2mm taller. The height is not as critical as the width of the entire 6 digit display and these look to have a footprint that would work.

Not sure yet how the 20 IDC cable connector mates to an arduino. The video doesn't get into that. I can make the flat cables though I don't have the 20 pin IDC connectors which Hispa sells as an accessory.

There is a statement in the description for the 6 digit display "To be directly connected to SimIO 32 displays board."
What does that mean?

Kaellis991
Posts: 581
Joined: Mon Sep 07, 2020 8:49 am

Re: 7 segment display Pin outs?

#183 Post by Kaellis991 »

I emailed Manolo.

His PCB and displays wont work with arduinos.

User avatar
jph
Posts: 2846
Joined: Fri Apr 10, 2020 12:50 pm
Location: Somewhere over the rainbow..

Re: 7 segment display Pin outs?

#184 Post by jph »

Kaellis991 wrote: Fri Dec 30, 2022 7:44 pm I emailed Manolo.

His PCB and displays wont work with arduinos.
You are asking the wrong questions :lol:
Of course they will work with Arduino !. They will work with anything. It is a cheap pcb (in the context of cheap is you haven't got any) :mrgreen:
It is important that you grasp that before we move on - or not :D
Joe
Joe. CISSP, MSc.

User avatar
jph
Posts: 2846
Joined: Fri Apr 10, 2020 12:50 pm
Location: Somewhere over the rainbow..

Re: 7 segment display Pin outs?

#185 Post by jph »

Kaellis991 wrote: Fri Dec 30, 2022 10:10 am Joe,

Those displays might work if I am reading this correctly. The displays I have are .2" (5.08mm) characters with a total length between centers of the 1st and 6th digit of around 35mm. It appears that at 33mm in length those are not any longer than what I was planning on using but about 2mm taller. The height is not as critical as the width of the entire 6 digit display and these look to have a footprint that would work.
Not sure yet how the 20 IDC cable connector mates to an arduino. The video doesn't get into that. I can make the flat cables though I don't have the 20 pin IDC connectors which Hispa sells as an accessory.
There is a statement in the description for the 6 digit display "To be directly connected to SimIO 32 displays board."
What does that mean?
Simio 32 is a crappy old system that has been around for years. Ignore it. The pinout is all you need to know. Just match it at you ardunio end
Not sure yet how the 20 IDC cable connector mates to an arduino. The video doesn't get into that. I can make the flat cables though I don't have the 20 pin IDC connectors which Hispa sells as an accessory.
You place a 20 pin IDC connector on your board that has the 7219 on. This then connects to the display via a 20 way IDC ribbon cable. :? It is fairly straight forward.
For a 7219 then the number of pins you need in the connector is 8 + (number of digits). Hence a 6 digit display is 14 pins.
Having 20 is good as it gives you a couple of extra pins for use for other things and is also a standard.
I mentioned to you before about the IDC crimp connector tool being cheap, so are the sockets, and plugs and cables. No real difference to using the type of stuff you are using with the crimp tool apart from this is a single crimp for all cables -
https://www.aliexpress.com/w/wholesale- ... .1000002.0
every (quality) commercial sim (for home use (and more) makes extensive use of IDC cables and connectors.
This is more or less the tool I use. It is very simple and has been around for about 50 years of more.
https://www.aliexpress.com/item/1005003 ... P2Nr2ibS4w

THE simplest toot to use for multi connections. You don't even have to prepare the cable apart from cutting it with a Stanley knife ( box cutter / 911 WMD :? ). No wire stripping. IDC = insulation displacement connector. That is why it is still used today.
Joe
Joe. CISSP, MSc.

Kaellis991
Posts: 581
Joined: Mon Sep 07, 2020 8:49 am

Re: 7 segment display Pin outs?

#186 Post by Kaellis991 »

I have all the IDC components to make flat ribbon cables. That's the easy part.

Alright, I was mistaken in thinking that that PCB eliminated the need for the max7219. I was under the assumption that it was a unit that didn't need the intermediate max7219 board.

Then I will need to build a board with the max 7219 chip plus the capacitors and resistors shown in the schematic you posted as well as an IDC male socket. What else does that board need besides a bunch of wires to make all the connections?

On such a circuit board how would you create the connections (i.e. the traces) from each of the IC pins to the capacitors / resistors and to the IDC connector?
With a regular perfboard do you run small gauge wires and solder them to the pins / holes? Or do you use solder traces to connect the holes on the perfboard?

Still, $40 in shipping for a couple of $1 parts is excessive. I was in the process of ordering the PCBs and the displays until I arrived at the shipping page....and then aborted the takeoff.
Remember, I live in the US and shipping to the states from wherever Hisapapanels is located is costly.

User avatar
jph
Posts: 2846
Joined: Fri Apr 10, 2020 12:50 pm
Location: Somewhere over the rainbow..

Re: 7 segment display Pin outs?

#187 Post by jph »

Hi Kirk,
For the 'trace
Use a good quality AWG 30 cable solid core. Similar to hook up wire or solid wire wrap type wire to make the 'traces' to the idc connector.
As for what other components you need on the board ?
For a 7219 then, along with the 0.1uF and the 10uF and the 10K Resistor that should be all.

If when working ok and tweaked then if needed, when you have a working board you can always have PCB's made.
Joe
Joe. CISSP, MSc.

Kaellis991
Posts: 581
Joined: Mon Sep 07, 2020 8:49 am

Re: 7 segment display Pin outs?

#188 Post by Kaellis991 »

Joe,

Happy New Year....

I have that circuit setup on a breadboard using (2] 4 digit displays as in the diagram. Since my displays are the castlellated SMD type I dont have a way of sticking them in the breadboard. Flexypins would help but I dont have any of those so I will take a couple of the displays I have and solder them to a board with standard or machine pins.

The wire is not a problem. I have plenty of 30ga solid wire that I have been using over the past year. Its such a tedious process but works.

User avatar
jph
Posts: 2846
Joined: Fri Apr 10, 2020 12:50 pm
Location: Somewhere over the rainbow..

Re: 7 segment display Pin outs?

#189 Post by jph »

Kaellis991 wrote: Sun Jan 01, 2023 10:46 am Joe,

Happy New Year....

I have that circuit setup on a breadboard using (2] 4 digit displays as in the diagram. Since my displays are the castlellated SMD type I dont have a way of sticking them in the breadboard. Flexypins would help but I dont have any of those so I will take a couple of the displays I have and solder them to a board with standard or machine pins.

The wire is not a problem. I have plenty of 30ga solid wire that I have been using over the past year. Its such a tedious process but works.

Same to you good sir ! - have a good one. :)
Yes, absolutely, it is a bit of a pain but the key is preparing the wires in advance ready for soldering with the ends stripped. It took me a while to find a really good wire stripper for 30AWG but they are obtainable. I used to use (and still have - and they are Still available!) a 'wiring pen' which uses coloured enamelled copper wire where the enamel will melt at around 400 - 420 C and so can be soldered. You can do point to point wiring but you need the correct iron and bit. Any good iron and bit capable of 450C is fine. I use an OKI 1100 series with an SCP 2.4 chisel bit but anything will do if the temp is adjustable and the bit stands up to the temps. No wire stripping involved then.
But, for small projects, is is, as you say, a pain, yet it is far easier in the long run than designing a schematic, routing it and providing a pcb layout. ordering from China receiving, finding they don't work because you got something wrong lol. Trimming and soldering 30 or 40 wires on two boards is not too bad really.
If I wanted 20 , I would probably consider a pcb, but only after breadboarding the circuit first.
Also consider using a small blob of hot glue to raise the castellated board for now and then make the connections by wire. ?
Maybe you have enough room in the unit to build a small board in the hardware that has both the 7219 AND the displays on ?
Joe
Joe. CISSP, MSc.

Kaellis991
Posts: 581
Joined: Mon Sep 07, 2020 8:49 am

Re: 7 segment display Pin outs?

#190 Post by Kaellis991 »

My Hakko soldering station has been good. I use it also for threaded inserts in my 3D prints.

There are a few options I have been looking at to drive these displays. Well really there are two ways right now.
1. Using the pre-made display modules with the onboard 7219, I see 2 ways to connect the board designed for 8 digits to the 6 digits that need to be closer together
a. One with lots of wires and connectors or
b. Using stacked boards to eliminate all the wires and connectors. The intermediate board provides a way to offset the pins from the 8 digit board to a DIY board with the 6 digits.
That intermediate board in the photo is one I already had manufactured by JLCPCB albeit I had to drill out a
a few of the traces and run some wire traces to do the cross-overs. I have a design for another board with the crossovers that I can send off for manufacture ( the EasyEDA schematic is what is shown on the blue PCB in my 3D model)
The compact stacked board configuration is what I need to fit inside my relatively narrow (90mm wide) radio enclosure.
2. Or creating my own module board with one (or 2) of my 7219s plus the other components
a. The board can be homemade on a typical solderable perfboard with lots of small soldered wire traces or
b. A PCB could be designed and manufactured....much more work with that one
The configuration of my radio enclosure could lend itself to utilizing one 80mm wide by 100 mm tall board for both the COM and NAV radios. (that will require some more design work)

The schematic below is my beginning attempt for the second option.
There are still things I do not understand about the wiring of the digits, but I think I understand the segment wiring.
The problem I am having is that I cannot find any diagrams on how to connect two (3) digit modules anywhere online, let alone how to cascade the second set of (3) digit displays for the second radio.

So I am trying to interpolate the 8 digit wiring connections I can find, and which you provided, to try and understand the rationale and concepts of 7-segment display wiring.
A simple single (3) digit display seems relatively easy but when there are more than one I get lost in the complexity.

I have yet to develop a clear picture in my mind of the 7-segment wiring concepts. Perhaps I am out of my depth when it comes to 7 segment displays as I am with many things electronic....

IMG_6121.jpg
image.png
image.png
image.png
image.png

Post Reply