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Topic: 4 DIGIT 12V 7 SEGMENT DISPLAY (Read 12584 times) previous topic - next topic

tangkaro

CAN ARDUINO DRIVE THIS KIND OF DISPLAY ( I FABRICATED DISPLAY USING LED STRIPS BUT IT USES 12 V SUPPLY) ? AND HOW? THANK YOU! :)

AWOL

Why are you shouting?
Why aren't you providing any details?

tangkaro

im gonna use 4 digit led display  as my scoreboard. the problem i thought was that can it be drive using arduino? should i use multiplexing? thanks

tangkaro

im sorry im newly registered here. i dunno if my post was right :D

PaulRB

im sorry im newly registered here. i dunno if my post was right :D
That's why this post is at the top of every section of the forum. But many newly registered forum members don't read it because they think it just says "be nice to everyone".

Arduino can drive a display made of 12V led strips, but not directly. You need some transistors or chips to handle the 12V directly because that would damage the Ardunino.

You can choose to multiplex or not to multiplex. If you choose to multiplex, you will loose some brightness, which may not be great if your display is for outdoor daytime use. But you can save some components.

I would recommend a tpic6b595 chip to drive each digit. Only 3 Arduino pins needed, and no multiplexing, for maximum brightness.

Paul

CrossRoads

#5
Jul 08, 2015, 02:49 pm Last Edit: Jul 08, 2015, 02:51 pm by CrossRoads
Yes, 4 TPIC6B595, one per digit, makes for a very easy scoreboard controller.
Can sink 150mA/segment from 12V.  LED strips are 3 LEDs in series with current limit resistor.
TPIC6B595 or TPIC6C595 are great for that. I offer a board with '328P for Arduino functionality and up to 12 chips/digit.
Plug on an FTDI Basic to program/debug your code, connect the LED strips, and away you go.
http://www.crossroadsfencing.com/BobuinoRev17/
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

tangkaro

woah thanks for the info. Im seeing topics like using 74hc595 and uln2003.. What do you think is the best

Paul__B

#7
Sep 14, 2015, 03:35 pm Last Edit: Sep 14, 2015, 03:37 pm by Paul__B
The ULN2003 is somewhat obsolete.  It uses Darlington pairs which have too high a voltage drop when turned on, leading to unnecessary heating and inefficiency.  The TPIC6x595 uses logic level FETs and is a shift register, meaning that you shift the data in serially using only three pins, and you can "chain" a reasonable number so you only ever use 3 pins.

The 74HC595 is not capable of driving any substantial current.

So we always advise the TPIC6B595 or another of that series as it combines the two functions perfectly, far better than the 74HC595 and ULN2008 combined.

You arguably could multiplex the displays, but if you really want maximum brightness, a separate TPIC6B595 for each digit is the best and then you do not need to be concerned about the coding for multiplexing. :smiley-lol:

tangkaro


tangkaro

i saw this diagram. even if i use several digits of display i will only use 3 pins on arduino board or 3 pins for each digit? :-)  so if only 3 pins on arduino for the 4 digit display of scores, then another 3 pins for the display of timer? thanks

PaulRB

You can use the same 3 pins for both displays, with all the tpic chips in a single chain. The clock pins from each tpic chip connect to the same Arduino pin and the latch pins connect to a different Arduino pin. The data-in pin from the first tpic chip goes to an Arduino pin and the data-out pin from the first tpic chip goes to the data-in pin on the second tpic chip and so on.

You could connect the /G pins to a PWM output on the Arduino if you want, so you can dim the displays if needed.

tangkaro

thank you. i hope i could find tpic6c595 in our place. if nothing, what is its counterpart? we need to start our prototype asap. :-)

Paul__B

#12
Sep 20, 2015, 10:45 am Last Edit: Sep 20, 2015, 10:47 am by Paul__B Reason: Always something more to be said.
The TPIC6B595 is a Texas Instruments part, possibly "cloned" by some other manufacturers in China.

It is a defined function, there is no "counterpart".

Whether genuine or "clone" (as always. hard to tell but generally work OK), they are readily available on eBay.

Let me put it another way.  If it is not available in your part of the world, we suggest you go back to using candles!  :smiley-eek:

PaulRB

#13
Sep 20, 2015, 11:17 am Last Edit: Sep 20, 2015, 11:18 am by PaulRB
if nothing, what is its counterpart?
You may be able to use 74xx595 and ULN2003/2803. This is not a great solution, as Paul__B already said, but if your displays are not too large, it would work. The problem is that if your displays are too large, the ULN chips could be overloaded. They would get hot and soon fail.

A second alternative would be 74xx595 and some transistors and resistors. You would need one transistor and resistor for every segment, so 28 in total. You could use bc337, with a resistor to limit the base current.

How large will your displays be? How many leds in each segment?

tangkaro

4x8 inch.. i will use led strips . each segment will have 3leds..

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