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Topic: 4 DIGIT 12V 7 SEGMENT DISPLAY (Read 12585 times) previous topic - next topic

PaulRB

#15
Sep 20, 2015, 12:25 pm Last Edit: Sep 20, 2015, 12:29 pm by PaulRB
4x8 inch.. i will use led strips . each segment will have 3leds..
In that case, 74xx595 and ULN2003/2803 will be ok.

Another option would be a saa1064 chip. This single chip can control all 4 digits with only a couple of extra transistors (e.g. bc337) and a couple of capacitors. Can you get saa1064?

tangkaro

i can now get tpic6c595N /tpic6b595n / tpic6a595ne .. program code is now the problem  :)

PaulRB

i can now get tpic6c595N /tpic6b595n / tpic6a595ne .. program code is now the problem  :)
Great. Choose the least expensive. Any of those will have enough current capacity for your displays.

Code should be easy. Have a look at shiftOut().

tangkaro

thanks. hope i can find example codes for selective countdown timer

PaulRB

hope i can find example codes for selective countdown timer
All newbies think there are "some codes" out there that do exactly what they need, written, presumably, by the code fairies. Write your own code! We will be pleased to help if you are making the effort.

AWOL

All newbies think there are "some codes" out there that do exactly what they need, written, presumably, by the code fairies.
They really exist!
Don't stop believing, children.

CrossRoads

Code to display a digit, for example:
Code: [Select]


#include <SPI.h>
byte fontArray[] = {
0b00111111, // 0   DP-g-f-e-d-c-b-a
0b00000110, // 1             a
0b01011011, // 2         f       b
:                                        g
:                                    e       c
0b01101111, // 9              d       DP
}

// MSCLR to +5
// OE/ to GND or to a PWM pin
// SCK to SRCLK
// MOSI to Ser Data In
// SS to RCLK

// to send out a digit
digitalWrite (ssPin, LOW);
// from an array of digits for example
for (x=0; x<numberOfDigits; x=x+1){
SPI.transfer(fontArray[digitsArray[0]]);

digitalWrite (ssPin, HIGH); // outputs update on this rising edge
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

i will write the code. though it will not be that precise. haha. no experience writing such code 'complex' for me. ahm i have a diagram .its for our thesis. im thinking if i should separate e 3 digits for my timer and use extra arduino pins for the 3 tpics. coz the timer will only be use for my time trial training mode unlike the score display. hm what do you think? and what is still lacking in my diagram. :) thanks

Paul__B

and what is still lacking in my diagram.
You show variable resistors connected to Vcc and pull-down resistors to ground.

In general, it is more practical and somewhat more robust in terms of interference and the risk of faults, to have the resistors connected to ground and the pull-up resistors (which will be on your circuit board) connecting to Vcc.

PaulRB

and what is still lacking in my diagram.
The clock and latch lines should go to each tpic chip in parallel, not just the first. Also add some caps. Each chip needs a 0.1uF bypass cap near its power pins. Also a larger cap (e.g. 470uF), or several meduim size caps (e.g. 100uF) to smooth the power when segments get switched on/off, on the 12V supply.

tangkaro


tangkaro

updated diagram. for my force sensor as variable resistor in the diagram. is this the better way to connect it to the arduino? and there still missing in the diagram? haha not good looking diagram

Paul__B


tangkaro


PaulRB

Still a few 0.1uF caps missing.

I don't understand why you do not want to chain all the tpic chips.

Not sure why you have those fixed resistors on the analog inputs. Its usual to connect the pots between 5V and GND and connect their wipers to the analog inputs.

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