# Display 4 digits 7 segments 12 pins

Good morning, I must do a project andI have to use one Display 4 digits 7 segments 12 pins with Arduino, but I don't know how to use it. I understand the simple one (whit one digit) but not the other. ¿How should I conect it whit my Arduino?

Thank you.

I must do a project

Is this homework?

How should I conect it whit my Arduino

You need to multiplex the displays. Is it common anode or cathode display? Use 4 transistor to switch one of the common connectors on a display so that only one display is activated. Wire all the other segments in parallel. Write code so that the display that is on changes at a rate of at least 30 times a second.

Are they common anode or common cathode digits?

Grumpy_Mike:

Is this homework?

No, it isn't. It's a small part of my final project for mechanical degree.

How should I conect it whit my Arduino

You need to multiplex the displays. Is it common anode or cathode display? Use 4 transistor to switch one of the common connectors on a display so that only one display is activated. Wire all the other segments in parallel. Write code so that the display that is on changes at a rate of at least 30 times a second.

really I don't know if it commom anode or cathode because I don't find the datasheet. The number is SH5461AS. Thanks for your explanation.

Thank you.

You're going to have to buzz it out then. Make a diagram with 12 pins. One pin will connect to all A segments, one to Bs, Cs, Ds, Es, Fs, Gs, and decimal points. One will connect to Anodes or Cathodes for Digit 1, a 2nd will be Digit 2, same for Digit 3 and Digit 4. See these as examples of what you're trying to find out: http://www.kingbrightusa.com/images/catalog/SPEC/CA56-12EWA.pdf http://www.kingbrightusa.com/images/catalog/SPEC/CC56-12EWA.pdf So, take a 1K resistor, connect one end to +5, use the other end as a +probe, and a wire to Gnd as a -probe. Be methodical and figure out what pins do.

http://www.instructables.com/id/4-Digit-7-Segment-LED-Display-Arduino/

As for the display pinout, why do people buy crap with no documentation? Anyway do as Crossroads suggests to figure it out.

Rob

I probed the pins and came up with this:

Each digit has 8 inputs, A-H

AA B C B C DD E F E F GG H

If you're looking at the front (display) side of the chip with the decimal places to the bottom right of the digits, then these are the pin numbers:

7 8 9 10 11 12

1 2 3 4 5 6

The pins are:

1 E 2 G 3 H 4 F 5 D 6 4 7 1 8 A 9 B 10 2 11 3 12 C

Where 1,2,3,4 are the anodes for each digit and A-H are the segments.

The layout looks a little funny. Usually its: AAA F B F B F B GGG E C E C E C DDD DP

The answer is - to use a MAX7219.

There is a frequent misunderstanding in regard to whether the display is common-cathode or common-anode. There is no problem at all with using the MAX7219 with common-anode displays, you simply exchange the digit and segment connections and it means you cannot use the built-in character generator which translates nybble values into segment patterns, so you have to define your patterns in software, but you would have to do that for any other means of driving the display in any case.

The number is SH5461AS.

Have you heard of Google ?

SH5461AS DATASHEET

chinese datasheet :Model No.: YSD-439AK2B-35 (SH5461AS equivilent)

(duh)

Is that so hard ?

This is a COMMON ANODE led matrix.

I see eight pins on either side. Anodes are pins 1, 2, 6, 8 (digit anodes)

[u]DIGIT[/u] [u]ANODE PIN[/u] 1 1 2 2 3 6 4 8

Anode (COLON) : pin 4 Anode "L3" ( I have no idea what this is for)

[u]segment[/u] [u]pin[/u] a 14 b 16 c 13 d 3 e 5 f 11 g 15 dp 7

Does this match your part ?

raschemmel: Anode "L3" ( I have no idea what this is for)

It is in an odd position. Usually to indicate the alarm is enabled.

I guess you learn something new every day. I've never seen a led matrix with that feature and I thought I had seen everything.

It's usually in one corner or another, such as DP4. Clocks usually have one indicator for alarm enabled and another for PM in 12-Hour mode (which I never use).

Paul__B: The answer is - to use a MAX7219.

^ this.. and very easy/direct to use.. (especially if you want to use the LedControl) library

Given Reply#9 and Reply#13, is there any reason why this post shouldn't be SOLVED ?