Hi
I plan to display numbers with led matrix (for a clock project), knowing that the matrix have 8x8 proportion, I think this square form is not very practical to display numbers with interessant design, according to you it is what is the best proportion? and have any idea for a digit display design?
Thanks
I try to do some Fonts with 8x5 proportion ... don't know if it's the best way ... 
Think about it. Character LCD, Graphic LCD, Graphic TFT, Graphic OLED or even LED matrix all involve fairly low resolution fonts. e.g. 7x5
7x5 works quite well. 8x8 looks pretty horrible. If you want to "improve" a 7x5, you add descenders. Thickening random parts of a letter does not work well.
Since you are limited to 8 rows of LEDs, your second example is more effective. (in my personal opinion)
David.
thank you David for your answer,
I try initially to define the best proportion, currently it is between the 8x5 and the 7x5, after I plan to put several fonts in my code and to integrate at the programming level the option to change fonts
Lots of low resolution fonts here :- Bitmap, pixel, screen fonts, small fonts, userbar | dafont.com
OK .. I made some samples .. can you help me to choose 4 or 5 fonts ... the ones you like most
Not much difference between #5 and #6.
I kind of like the font used in hd44780 LCDs when used on lines.
They use 5x7 (the upper 7 rows/pixels) and use the bottom row for underline or a cursor.
However, you haven't said how you are physically arranging the modules.
So, one thing to consider is the over all display and the spacing between the LED matrix displays.
Depending on spacing, it can create issues or benefits.
For example, when there is no space between matrix modules, the pixels of the characters can run together and make things harder to read depending on the font.
However, if the 8x8 matrix modules are butted up with no spaces, you can take advantage of using fewer than 8 pixels across to get more characters across than you have 8x8 modules.
i.e. if you have six 8x8 modules that gives you 48 pixels, at 5 pixels per character plus 1 inter character gap you can get 8 characters.
8x8 fonts can look ok if you get a nice cp437 font.
The cp437 font is nice because it can be used for some primitive graphics as well.
I'm not sure how you are implementing the h/w but I'd start with one of the larger matrix displays available on ebay. Like a 32x8, 32x16, 24x16, 64x16, etc... display. Some are red/green which gives you three colors per pixel.
They typically interface using SPI so here is no complicated wiring and many use chipsets that have arduino libraries for controlling them.
--- bill
thank you Bill for your answer,
bperrybap:
Not much difference between #5 and #6.
...
the numbers 1, 2, 3, 4, 6 and 9 arn't the same .. a little difference .. but not the same
bperrybap:
...
I kind of like the font used in hd44780 LCDs when used on lines.
They use 5x7 (the upper 7 rows/pixels) and use the bottom row for underline or a cursor.
...
no much difference between 5x7 and 5x8, I think it gives more length to the numbers and it's more beautiful ... no ?
bperrybap:
...
However, you haven't said how you are physically arranging the modules.
So, one thing to consider is the over all display and the spacing between the LED matrix displays.
Depending on spacing, it can create issues or benefits.
For example, when there is no space between matrix modules, the pixels of the characters can run together and make things harder to read depending on the font.However, if the 8x8 matrix modules are butted up with no spaces, you can take advantage of using fewer than 8 pixels across to get more characters across than you have 8x8 modules.
i.e. if you have six 8x8 modules that gives you 48 pixels, at 5 pixels per character plus 1 inter character gap you can get 8 characters.8x8 fonts can look ok if you get a nice cp437 font.
The cp437 font is nice because it can be used for some primitive graphics as well.I'm not sure how you are implementing the h/w but I'd start with one of the larger matrix displays available on ebay. Like a 32x8, 32x16, 24x16, 64x16, etc... display. Some are red/green which gives you three colors per pixel.
They typically interface using SPI so here is no complicated wiring and many use chipsets that have arduino libraries for controlling them.--- bill
Here is an overview of the project I plan to do :
My personal preference is #6
Judging by your "overview", I am convinced that my preferences are different to yours.
David.
david_prentice:
Judging by your "overview", I am convinced that my preferences are different to yours.David.
LOL 
Having seen the face of that clock you're building, I think you should go for some retro / creative font.
Something like numbers 4 or 7.
But i'm not sure how well one could read that.
Like David, i wouldn't use such fonts myself but that doesn't matter.
It's your project.
You've already drawn your characters, can't you pick a few and test them in the almost ready product ?
Shouln't be too hard to change fonts.
david_prentice:
My personal preference is #6Judging by your "overview", I am convinced that my preferences are different to yours.
David.
and it's perfectly normal ....
MAS3:
... Shouln't be too hard to change fonts.
my idea is to put several fonts in the arduino code and add a button that will allow to change fonts ... possible no?
Have you decided your circuit design?
If you were to use an ESP8266 module with a 8x32 matrix it would be very easy to wire up.
The reason I mention using an ESP part is that they are very small and you could use the wifi for configuration (using a web browser on your tablet, phone, pc, etc...) as well as getting time from a time server so you also won't need a real time clock battery, buttons, or switches.
And you can could have it automatically do daylight/summertime time adjustments.
If you put a piece of paper or onion skin over matrix, you won't see it but can easily see the leds that are turned on.
--- bill
well ...
actually my current circuit diagram is based on a DS3231 clock, a Si7021 temperature and humidity sensor, and MAX7219 to control the LED matrice ... but if you have better proposals I'm a taker ...
What about the "arduino".
The esp8266 parts are cheap, have gobs of resources and you can do some amazing things since it includes wifi.
7219 is fine. I'd recommend buying premade modules or a "4 in 1" module. 4 in 1 modules cost about USD $6 off ebay.
It isn't worth trying to wire them up as the part cost will likely be more and the amount of wires to deal with is extremely painful and can get very messy.
If you go the 7219 route, you may want to consider the parola library as you can then scroll messages and have some fancy effects as well.
wifi capability adds lots of potential. Examples:
--- bill
I am interested by adding a wifi card in my project ... with all the possibilities that it can offer this addition
but my test with a wifi chip is a failure, I tested the chip esp8266 12E, I have not success to make it work properly, I think I chose the wrong model (12E), finally, I nothing against a new test with a good chip
Thanks
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