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Author Topic: radioshack 7-segment red led 0.3" digital display help please...  (Read 3079 times)
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Rhode Island - USA
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i just bought my son a couple of radioshack 7-segment red led 0.3" digital displays.. (since we are awaiting different ones to come in that we bought on ebay.. the pins are different). i haven't found any real tutorials on these, and i have come across other people having the same issue..

the back of the package says:

 
1. anode F
2. anode G
3. no pin
4. common cathode
5. no pin
6. anode E
7. anode D
8. anode C
9. anode RHDP
10. no pin
11. no pin
12. common cathode
13. anode B
14. anode A



have a look here for back of package..

http://images2.powerreviews.com/media_popup.html?type=image&url=http%3A%2F%2Fpowerreviews.s3.amazonaws.com%2Fimages_customers%2F00%2F46%2F19554502_142158_full.jpg

can anybody please tell us exactly how to hook this up... we have an arduino 2560...

thank you..
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Manchester (England England)
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What is wrong with this:-
http://www.hacktronics.com/Tutorials/arduino-and-7-segment-led.html
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How are you planning to use it - multiplex by driving 1 anode High at a time while the common cathodes are connected to each other with a series resistor to Gnd?
Or by driving all anodes at once each with their own series resistor, with the 2 common cathodes connected to Gnd?
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we just want to make it work lol..

seriously tho,we want to click a button and make it count up and then start over i'm not sure about what you are asking, it's our first digit led

based on the exact one, we just would like to wire it up, but have not seen any tuts for this specific 7-segment led

basically we just don't get this thing, no matter how we wire it up...



@grumpymike
we want to know how to hook this one up, pins are lined up differently (we also don't see a pin 14... 13 is the highest)... so that loses us right there.

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Quote
13 is the highest
But you posted pin 14's connection in the original post.

Sure the pin numbers are different but the circuit will be the same, just change it to the pin numbers you have.
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ok, keep in mind we are new to arduino and all this.. so we don't understand as much as you guys..

does each pin require a resistor? if so, which?


i thought this thing was going to be fun, so i bought the arduino for my son and a bunch of misc parts on ebay.. so we don't have everything we need, but slowly getting it and getting the parts we need.

so please be patient... i don't want every post i make to turn into an argument with people on here...

if there is a schematic for the exact one we have, we would like to see it... we never wired up a digit led before. we just don't get it atm
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Tutorial                       Your Display
Segment A pin 7         Segment A pin 14
Segment B pin 6         Segment B pin 13
Segment C pin 4         Segment C pin 8
Segment D pin 2         Segment D pin 7
Segment E pin 1         Segment E pin 6
Segment F pin 9         Segment F pin 1
Segment G pin 10       Segment G pin 2
Cathode  Pins 3 & 8     Cathode Pins 12 & 4

Quote
does each pin require a resistor
Yes. Try 220R but it is not too critical.
« Last Edit: January 03, 2013, 05:09:35 pm by Grumpy_Mike » Logged

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ty, i will try that..
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ok, that didn't work.. also, according to the top part of the coding - there is no mention of pin 10

Quote
void setup() {             
  pinMode(2, OUTPUT);
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(7, OUTPUT);
  pinMode(8, OUTPUT);
  pinMode(9, OUTPUT);
  digitalWrite(9, 0);  // start with the "dot" off
}





tutorial                  my display

Segment A pin 7         Segment A pin 14
Segment B pin 6         Segment B pin 13
Segment C pin 4         Segment C pin 8
Segment D pin 2         Segment D pin 7
Segment E pin 1         Segment E pin 6
Segment F pin 9         Segment F pin 1
Segment G pin 10        Segment G pin 2
Cathode  Pins 3 & 8     Cathode Pins 12 & 4

here is how i have it hooked up...

#14 is connected to pin 7
#13 is connected to pin 6
#8 is connected to pin 4
#7 is connected to pin 2
#6 is connected to pin 1
#1 is connected to pin 9
#2 is connected to pin 10
# 12 & 4 are connected to ground on bread board
#9 is not connected at all

resistors are connected to ground on breadboard to their digit led pin wire.. using 5x 220 and 4x 680 because i don't have anymore 220's

here's what it's doing: http://www.youtube.com/watch?v=AmpHS7wT_bU&feature=youtu.be

ground is connected to arduino mega 2560 from the breadboard

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Quote
according to the top part of the coding - there is no mention of pin 10
That is because the arduino pin 10 is not involved.

I think you are getting mixed up with what is a pin on your display and what is a pin on the arduino board.

Quote
here is how i have it hooked up...

#14 is connected to pin 7
#13 is connected to pin 6
What does the # denote? If it is an arduino pin then

Quote
resistors are connected to ground on breadboard to their digit led pin wire
The resistors should be connected to the arduino pin and the other end of the resistor should be connected to the appropriate segment anode of the display.
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# denotes the number on the back of digit led package as stated in the main post..

http://www.youtube.com/watch?v=NmZxbzDDAmA&feature=youtu.be

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Sorry I can't make anything out from that video.
Quote
#6 is connected to pin 1
So if that is pin 6 on the display connected to pin 1 of the arduino it is not correct.
Arduino Pin    your display
 2        resistor         14
 3        resistor         13
 4        resistor         8
 5        resistor         7
 6        resistor         6
 7        resistor         2
 8        resistor         1
 ground                 12 & 4

Your display is numbered so that pin 1 is the top left hand corner looking at the front of the display.
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ok, that works better.. but some numbers are in complete or have an extra led on.. ex for 3 it shows A,B,G,C,D & E

and for 5... it shows A, F G and C but not showing D

2 doesn't even show, 0 is missing C


for experimental purposes, i put #9 with #7 on the breadboard.. the dot lights up when it's supposed to (i guess)... but that's neither here or there..

complete numbers i do get are: 1, 4, 5, 6,7, 8, 9 (5 had a loose resistor)

http://www.youtube.com/watch?v=mvhG249CrwM&feature=youtu.be
« Last Edit: January 04, 2013, 11:33:32 am by Ruffsta » Logged

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OK it is debug time.

First off check that each segment is controllable independently.

Write a sketch that just puts one segment on and check it is right. Repeat for all 7 segments. Maybe you could write a sketch to to that all in one go but I am assuming you can't.
Code:
int totest = 2;
void setup(){
pinMode(totest, OUTPUT);
digitalWrite(totest, HIGH);
}
void loop() { }
Change the number assigned to totest one at a time until you have covered all the segment pins.
If that works then it is a software error you have made, if it doesn't then you have a wiring error.
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for 1 shows: nothing
for 2 shows: A
for 3 shows: B
for 4 shows: C
for 5 shows: E,D
for 6 shows: E,D
for 7 shows: G
for 8 shows: F
for 9 shows: nothing
for 0 shows: nothing

my connections are:
arduino pin 2 = led 14


the only numbers messing up are: 0, 2, & 3
arduino pin 3 = led 13
arduino pin 4 = led 8
arduino pin 5 = led 7
arduino pin 6 = led 6
arduino pin 7 = led 2
arduino pin 8 = led 1

led 12 & 4 are ground


the only numbers messing up are: 0, 2 and 3
« Last Edit: January 04, 2013, 11:35:39 am by Ruffsta » Logged

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