Questions tagged [7segmentdisplay]

A numeric display consisting of seven segments per digit, allowing characters 0 to 9 to be displayed by selecting which segment is on or off. Can have each digit independently controlled, or can be multiplexed to reduce pin count. An 8th segment can be included for a decimal point.

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42
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5answers
6k views

Why do 7 segment LED displays break apart when I brush my teeth?

This question might sound silly, but it is very serious (although geeky, I must admit). When I use my electric toothbrush in front of my alarm clock (one of those with a big red LED display), the ...
22
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4answers
4k views

Why does the seven segment display have decimal point at the right? [closed]

All the seven segment displays I’ve seen so far have their decimal point to the right of the main digit. Why is this so? A decimal point to the left will be able to represent more possible ...
18
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4answers
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Why did my LED resistor burn while lighting four LEDs in series?

I have tried to create a circuit to switch a large 7-segment LED display (LDS-CD16RI) using a pair of MOSFETs, as follows: simulate this circuit – Schematic created using CircuitLab Here I am ...
17
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2answers
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Seven-segment display seems to draw little current

I bought a 1.8-inch seven-segment common cathode LED display from AliExpress. So no datasheet available. I used a 1 kΩ resistor and a 5 V source, as to put a max 5 mA in the LED. I measured 1.6&...
12
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3answers
5k views

Low power, seven segment display

I want to display a 4 digit number on a small device that fits in a hand. I have a CR2032 3V battery at around 230mA, my microprocessor is a 8051 (in a BLE112) usually uses about 0.9µA and I want the ...
9
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1answer
20k views

Using 4 digit 7 segment LED

I have a 7 segment display that has 4 digits. What will I need to make use of this? Can a single microcontroller handle the operation? I mean PIC16F690...I saw also a MAXIM chip that drives these kind ...
7
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4answers
5k views

4026 + 7-segment display: do I need transistors?

I'm a beginner and, as an exercise, I'm building a digital clock using without a microcontroller. The main IC that I'm using is a 4026, which counts and converts do 7-segment led format. The leds in ...
7
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3answers
10k views

Improving brightness of multiplexed 7-segment led display

I have a two digit 7-segment LED display which is driven multiplexed by a microcontroller. PORTA is for the anodes. In my code I shift a 1 through ...
6
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10answers
16k views

7 segment binary to hex

I'm trying to display a 4-bit binary number on a 7 segment LED as a hexadecimal number (0-F). I have an assortment of 7400 series ICs including the 7447. But that one only works for BCD (0-9). The ...
6
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3answers
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Why can't resistors be used to connect cathode pins to GND instead of segment pins to VDD with a 7-segment display?

When using a common cathode 7-segment display, is there a reason that two resistors can't be used to connect the two cathode pins to GND instead of using seven resistors to connect the seven anode ...
6
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1answer
931 views

Multiplexed Display

Need to develop a user display for a home appliance with: Two digit temperature display (Seven Segment). Four LEDs for 'Power ON' and three 'Modes of Operation' of the appliance. I came across a ...
6
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2answers
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7-segment LED display with multiple digits

I was looking at the datasheet for the LTC-4627JR, and it looks like each digit shares a common anode, and each segment shares a common cathode. My question is given this configuration, I don't ...
6
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2answers
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Multiplexing 2 digit 7Segment with one Bit

I want to control a 2 digit 7-segment LED with a MSP430 micro controller. The display has 8 input pins per digit (8th pin is the dot, which I do not need) and two ground pins (common cathode). The ...
6
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1answer
2k views

LCD modules with I2C or SPI interface [closed]

I would like to add an LCD to my current design (a project that is to be produced in low volume, around 50 to 100 units). A small display size (around 8 or 16 characters) should be plenty since it is ...
6
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2answers
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Reverse engineering a 12 pin LCD?

I just found a broken "laser projecting alarm clock". I took it apart, and am interested in only the laser projection arm. This consists of a laser diode (although I suspect that this is actually just ...
5
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7answers
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Binary coded decimal ICs

Is there any IC that can be use to convert 9 bit binary code to seven segment display? EX: 100101100->300 I want to display 300 in seven segment display when 100101100 binary code applied to input.I ...
5
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5answers
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Displaying a 2-digit integer on two 7-segment display

I'm having trouble displaying a binary number into a display. I'm not sure of how to split a number in binary into its individual numbers. For example, if I want to display 25, I want to split this ...
5
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3answers
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Is the there an intended PCB layout for the MAX7219/MAX7221 I'm missing?

The ordering of the segment pins (14-17, 20-23) on the MAX7219/MAX7221 common-cathode LED display driver is unusual, to say the least: The order of these pins is similar, but not identical, to the ...
5
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1answer
267 views

7-Segment Decoder outputs/LED display

What would be the difference in using a 7-segment decoder with active-high outputs vs active-low outputs, to driver an LED display?
5
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4answers
2k views

What's the best way to connect a 4-digit 7-Segment LED to Atmega168

I'm working on a device with a 4-digit 7-segment counter and wondering what is the best way to drive all the LEDs. Right now I have a custom PCB that's driving them all from an Atmega168, using most ...
5
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1answer
8k views

Alarm Clock 7 Segment LED display

I recently got an alarm clock from goodwill and took it apart and am probably going to use the display for some tests. Here is a picture of the front of the display: The text on the left is YC-60525S ...
4
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3answers
10k views

Cheap 4 digit 7 segment display driver

Can anyone recommend a cheap ( less than $4 ) driver chip capable of driving a 4 digit, 7 segment display with the center colon? I'm very familiar with the likes of the MAX7219 and similar but they ...
4
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3answers
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Why does this 7-Segment Display not function properly?

I've provided details in image. Although, I'll once again provide in text: IC : 74LS47N (Binary to 7-Seg Display) 7 Segment : Common Anode M.S.B : D L.S.B : A This ...
4
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6answers
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How to power 24 7-segment displays with Arduino?

I'm working on an Arduino project where I need to power 24 7-segment displays (model Kingbright SC56-11YWA). I decided to control them using 8 bit shift registers (model 74LS164N). This is ...
4
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5answers
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Why is there a delay in a common anode 7-segment display?

I have a common anode 4-digit 7-segment display. I have each segment cathode connected to a 330-ohm resistor, and the resistor is connected to a shift register. Each segment cathode is connected to ...
4
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3answers
2k views

Can a laser display numbers like an LCD 7 segment display? [closed]

Possible Duplicate: Is there a way to convert a 7 segment display to be displayed by a laser beam? I am a 12 year old child with a growing interest in electronics. I want to have a laser project ...
4
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2answers
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Driving 7 segment displays through Raspberry Pi's GPIO

So I was thinking of wiring up four 7-Segment displays through the Raspberry PI. I'd do that by multiplexing each of them, and came across this: http://hackyourmind.org/public/images/display7seg_anim....
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2answers
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Shift Registers Controlling Seven-Segment Display without a Latch?

I'm restoring a Model H Skee-Ball machine, and these old models have a bunch of hardcoded settings and unreliable switch detection, so I want to replace the main control circuitry with something ...
4
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2answers
1k views

Need help finding smallest possible 8 digit 7 Segment LCD TN Display

I can find a number of LCD TN 8 digit 7 segment displays but they are far to big. The kind of size I'm looking for is the ones you usually find in mini calculators. The size im looking for is around ...
4
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1answer
7k views

MAX7219 Arduino Issue with 7 Segment display

I have followed the tutorial here MAX7219 Now when i wire it up to a 4 Digit 7 Segment display, and run any code changing the display I get all the segments on all digits lit up ...
4
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1answer
713 views

7-segment output: 4-6V, LCD input: 3-5V. How to convert?

Problem: I am thinking of using a chip that gives out 4-6V on 7-segment output pins but the LCD only wants 3-5V input, so I need to convert somehow. The display is a TN type, drawing virtually no ...
3
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4answers
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Using a 7 segment display to show numbers 1, 2, 3 and 4 with four inputs

I have in my car 4 LEDs which illuminate in the instrument cluster depending on the gear the vehicle is in. This is a factory standard setup which I have already run feeds from ready for the next part....
3
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3answers
241 views

I am designing a 7 segment display but I am finding it a little bit hard to associate them

I am new in this domain and I want to design a 7-segment display from 0 to 9 and then from A to F. I made the truth table composed of 4 inputs and 8 outputs each output for the corresponding pin of ...
3
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3answers
57k views

How to connect 7447 decoder to 7-segment display?

I've connected a 7447 decoder to 7-segment display as shown in figure. When I connect an input, the LEDs doesn't form numbers but they light up randomly. I just want to know the right way to connect ...
3
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5answers
4k views

Need a LED Display

PROJECT: I'm building a Digital Clock controlled by a Arduino micro-controller. I want it to display the hours, minutes and seconds on a LED Digit Display. Therefore, I need to have several digits, ...
3
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2answers
585 views

Using NPN Darlington to switch on PNP

I'm trying to separately switch on the digits of a 2 digit common anode 7 segment display (specifically the Lumex LDD-E2802RD because it's small and cheap). I think that the easiest way of getting my ...
3
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2answers
549 views

How to “deserialize” a digital output to 4 digital outputs

I am working on a small test project for my Arduino and as part of it, I want to display a number on a 7-segment LED system. My first setup involved just direct links to the 7-segment display and ...
3
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2answers
13k views

How to drive a 12V common cathode 7-segment display with 5V signals and BJT transistors?

I'm having trouble designing a driver for a large (5") 12V common cathode 7 segments display using a 74HC595 shift register and BJT transistors. Below are the schematics for the component (display) I ...
3
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1answer
2k views

Seven segment display becomes dimmer as more segments are lit

I've got a common cathode, two digit seven segment display (LDD-N512RI-RA) hooked up to the GPIO pins of a microcontroller (Coldfire MCF52233 DEMO). The problem is that the brightness of the display ...
3
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1answer
2k views

Driving 3 digit seven segment using Arduino Uno R3 and a Demux

I have to light up 3 digit 7 segment displays using Arduino Uno R3. I have got myself 3 BCD-to-7 segment display decoders. I figured I need a 4-to-16 Decoder, so I bought one and it turned out that it ...
3
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1answer
419 views

How to “unground” a low state of a not gate

I have a seven segment display(LTS4680AE) and the anode of each segment keeps getting grounded. So I basically have a 4 bit adder which adds two 4 bit numbers and produces a 4 bit output. This output ...
3
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1answer
300 views

Why is my LCD stop to work correctly when my pump is running? [duplicate]

I have a 8x8x8 lcd/led/button module (tm1638 chip) connected to my Arduino r3. When I attach a pump (GPH350, 1.5A, 12V to the same power supply (12V, 5A) - my display stops working correctly (only ...
3
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2answers
4k views

Arduino + Max7221 + Common anode 4-digit 7-seg LED array?

I'm trying to hookup a common anode 4-digit 7-segment LED array to my Arduino via a Max7221 IC. Here's a hard-to-see (sorry!) pinout for my LED array (my LED array is the bottom common anode one, ...
3
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1answer
887 views

Reverse engineering 7 segment display

I ran into a problem with one of my hobby projects and at this point I need some help. I'm attempting to sniff the signals going into a 7 segment display and use them for a purpose. The display is a ...
3
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1answer
1k views

How to use Darlington arrays to source current in a 7-segment display driver

I'm building a driver for a large common-cathode 7-segment display using a shift register and BJT transistors (more details in this question). I wanted to make it more compact by replacing the ...
3
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1answer
2k views

LED Driver IC STLED316S

I am struggling with reading the datasheet for the STLED316S 7-segment/Discrete LED driver IC. I'm writing code for an STM32 chip, but also using Arduinos as well. I'm having no problems writing the ...
3
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1answer
790 views

How to read SAA1064 7-segment values

I have a central heating system that displays it's info and error codes on 4 7-segment displays. These displays are driven by a SAA1064, like so: This SAA1064 (datasheet here) receives it's ...
3
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2answers
11k views

Weird ULN2003 to 7-segment behaviour in Proteus

I'm trying to drive a 7-segment common anode, in the following connection, however there is no output the comes from the ULN2003 at all, its like when it gets a 0 in the input, it gives a tri state ...
3
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1answer
548 views

Strange Results With a 3x7 Segment LEDs

I'm trying to get a CPS03631BR 3 digit 7 segments LEDs to work. I've wired it to my Arduino UNO like this: And I'm using this code, which should light all the LEDs digit-by-digit, then light ...
3
votes
1answer
153 views

Timer activated by Reed on AC solenoid

Let me start by saying thank you for taking the time to read this - I really appreciate it! To the point: I am trying to create a 2-digit timer that resets and then starts at the activation of an ...

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