4 digit 7 Segment Display ..help?

I have been looking all over the net for a .36" 4 digit 7 segment display with an attached IC and board.
The only ones I see with an IC are those configured with a colon for a clock display and mounted on a board with a TM1637. The 4 digit displays I can find without the colon are bare without a shift register.
I want the KT76C transponder I am trying to build to look like the one here on the Simvim website which is similar to the real thing. https://simvim.com/config.html

Does such a 7 segment display even exist? Or do I have to make my own with a 74HC595...not sure I have the skills for that.
Or is a 74HC595 breakout board something I can use? If I can find that....

After a couple of months of research and reading and reading and research and asking questions I am exhausted.

This 7 segment display issue might just be the last straw.....

take one of these 8digit 0.36 displays with MAX7219 on the GREEN pcb.
The displays on the boards with green pcb have sockets and you can remove one 4digit module (or expand the wires and use one for another display).

by the way, there are also some 4digit displays available, but I would always prefer the MAX7219.

OP’s link: https://simvim.com/config.html
Please use the link icon when posting links.

Can’t see a 7-seg display on that page…

74hc595, despite what you may have heard/seen, is really unsuitable for driving 7-seg displays. It’s cheap, but many such circuits exceed the chips limits, shortening its life.

Unfortunately that link only gets you to the main page. The pop up images do not have a URL. Selecting the box labeled “XPDR devices” shows multiple options. The KT76C on the left of that pop up image is the display I am trying to emulate.

When I begin a new topic I do not see a “link” icon anywhere. Down at the bottom there is a button for attachments and other options. Where is this link icon?

Just so I am clear on this, the 74HC595 is to minimize the number of pins used on the Mega 2560 to drive all the segments. That IC can either be attached to a board that the display is mounted on or there can be a separate “breakout” board with the 74Hc595 on it that can do the same pin reduction?

But if the 74HC595 is not the way to go then what is? Are separate 4 digit displays each with a TM1637 mounted together on their own board a better way? I have an 8 digit with the MAX7219 but I can’t find any 4 digit or 3 digit displays with that same driver. I have assumed that the MAX7219 is specifically for the 8 digit display which is two 4 digits mounted on a single board. Is that a correct assumption?

If so then wouldn’t I want the MAX7219 driver somehow connected to two separate 4 digit displays but with a space between the displays? The green board that has plugin displays on Aliexpress sounds like what I would need but it would require some wires to move the displays apart.
But is it even possible to build a board with the displays hardwired to a MAX7219 but with the displays separated by a couple of inches but on the same board. That 2” or so space would be where the LEDs could be mounted for the annunciators.

I am just spitballin here...with a lot of naivety.

kaellis991:
When I begin a new topic I do not see a “link” icon anywhere. Down at the bottom there is a button for attachments and other options. Where is this link icon?

It is the "chain" icon above the "Reply" window itself.

Always use "Preview" to see what your post looks like before the final posting.

And do not add offensive comments such as "help" or "urgent" to your subject line. That makes some people ignore them just on principle. :roll_eyes:

kaellis991:
But is it even possible to build a board with the displays hardwired to a MAX7219 but with the displays separated by a couple of inches but on the same board. That 2” or so space would be where the LEDs could be mounted for the annunciators.

Of course it is! :grinning:

Just take the socketed version of the 8 digit display, pull off one 4-digit LED module and wire it pin-for-pin to the positions from where you removed it. Or you can not connect the decimal segment to that display and use it to drive four annunciator LEDs instead.

Of course you can get TM1637 modules with decimals rather than a colon. You just have to look for them.

The limitation is that you need a separate two output pins to drive each TM1637 while you can drive quite a number (at least 8 ) of MAX7219 modules as a chain with only three pins.

I have an 8 digit with the MAX7219 but I can't find any 4 digit or 3 digit displays with that same driver. I have assumed that the MAX7219 is specifically for the 8 digit display which is two 4 digits mounted on a single board. Is that a correct assumption?

If so then wouldn't I want the MAX7219 driver somehow connected to two separate 4 digit displays but with a space between the displays? The green board that has plugin displays on Aliexpress sounds like what I would need but it would require some wires to move the displays apart.
But is it even possible to build a board with the displays hardwired to a MAX7219 but with the displays separated by a couple of inches but on the same board.

where should we start: the MAX7219 is a dedicated driver IC especially build to drive LEDs. you can connect "8rows - 8 colums" matrix which will give you 64 LEDs. If you only use 4 x (7+1) LEDs - your IC will still be fine. There is even a register, where you can tell the MAX "I only have 4 digits connected".

And yes, a "couple" of inches/cm after the MAX to the LEDs will still work.

Most of my web browsing is done on my iPad. No such chain icon appears below the “Message Icon:” as it does on my Windows machine. Probably a flash issue.
Thanks for the links but I will always have a problem with purchasing from Aliexpress.

Paul__B:
(snip)
And do not add offensive comments such as "help" or "urgent" to your subject line. That makes some people ignore them just on principle. :roll_eyes:
(snip)

That's rather odd behavior on a forum whose purpose is to "help" i.e educate others.

kaellis991:
That's rather odd behavior on a forum whose purpose is to "help" i.e educate others.

I agree. I'm my opinion there is no offence in asking for help, as you have done. No offense, but at the same time, it adds nothing. Everyone assumes that is why you posted, because that is what the forum is for :smiley:

Some newcomers to the forum demand help with subjects containing "HELP" (capitals/shouting) or "HELP!!!" and I agree with Paul that they annoy me too and make me less likely to want to help them. Worse still is adding "URGENT", "ASAP" and similar words. This is a community forum, no-one is in any way entitled to demand help here.

kaellis991:
Most of my web browsing is done on my iPad. No such chain icon appears below the “Message Icon:” as it does on my Windows machine. Probably a flash issue.

My Android tablet and phone show this:


The Link icon is 12th from the left. You do not see this on Apple?

PaulRB:
My Android tablet and phone show this:


The Link icon is 12th from the left. You do not see this on Apple?

Nope.. my newest Apple mini iPad does not display that graphic. And what's more my old ipad 2 wont even display the login menu bar at the top. IOS issues no doubt.

PaulRB:
I agree. I'm my opinion there is no offence in asking for help, as you have done. No offense, but at the same time, it adds nothing. Everyone assumes that is why you posted, because that is what the forum is for :smiley:

Some newcomers to the forum demand help with subjects containing "HELP" (capitals/shouting) or "HELP!!!" and I agree with Paul that they annoy me too and make me less likely to want to help them. Worse still is adding "URGENT", "ASAP" and similar words. This is a community forum, no-one is in any way entitled to demand help here.

I guess I was thinking that if I saw a title that just said "4 digit 7-segment display" it might be a post from someone that was not looking for information but wanted to impart information. Semantics and communication underlies much of what makes this world function or not function.

so you really want an advise for a proper title?

"Searching for 4 digit 0.36" 7 Segment LED display modules (but not from Aliexpress)"

the buttons can be activated in your profile/forum settings. I guess it's

"Use full editor in Quick Reply"

noiasca:
"Searching for 4 digit 0.36" 7 Segment LED display modules (but not from Aliexpress)"

Eh? Am I missing something? I do not recall the OP stating they did not wish to purchase from Aliexpress.

I gave links to an Aliexpress listing for the sort of display the OP requested, with decimals, as eBay now chooses to prevent "hotlinking" to their images. Apparently they do not want me (or others) to advertise their products on their behalf, so I must advertise Aliexpress instead. :roll_eyes: Mind you, I find the prices better on Aliexpress at present.

I did order one of these in the process of my search! :grinning:

I am not sure the OP appreciated my explanation of how to turn 8-digit MAX7219 modules to their purpose. :astonished:

If you do not explicitly need MAX7219 display, Adafruit makes nice 4 digit backpacks with 4 digit displays, in a few different colors: Adafruit 0.56 4-Digit 7-Segment Display w/I2C Backpack - Yellow : ID 879 : $9.95 : Adafruit Industries, Unique & fun DIY electronics and kits
They are very easy to control and very bright, its just their library doesnt allow as many controls as the one for MAX displays.

Also, you can easily make your own PCB for MAX chip and then split displays in 2x4 digits.

I did this for my latest clock project:

All displays here controlled by MAX7219

EDIT: ahhh, just realized you are looking for 0.36" displays. I am using similiar ones for my clock and made a custom PCB so i can use 4 digits display only or 2 combined if needed. I got my displays from mouser: LTC-4727JS Lite-On | Mouser Österreich
These are 10mm so more like 0.39" if that would be ok for your needs.

Cheers,
Alek

Eh? Am I missing something? I do not recall the OP stating they did not wish to purchase from Aliexpress.

he does, see post #6

Thanks for the links but I will always have a problem with purchasing from Aliexpress.

but when one sees different options on Ali, he can search on his preferred platform anyway.

By the way, did I ever mention in this thread that I have nice libraries for the MAX7219 and for the HT16K33. Nice - at least in my humble opinion :wink:

https://werner.rothschopf.net/201909_arduino_ht16k33.htm
https://werner.rothschopf.net/201904_arduino_ledcontrol_max7219.htm