Questions tagged [led-matrix]

Anything related to LED matrices. A LED matrix is a rectangular arrangement of LEDs where all LEDs in a row have their cathode (or anode) connected to the same line and all LEDs in a column have their anode (or cathode) connected to the same line. In this way a single LED can be lit supplying power to the lines corresponding to its row and column coordinates.

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132 views

74HC595 8x16led matrix arduino

I'm currently trying to learn how multi shifting is working and have therefore started a project where I wanna drive 2X 8x8 LED matrix with an Arduino. I have found it that I should work with the ...
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103 views

Best practice to switch on 4 power supplies from one single source

First of all, I am a self taught maker with a passion for LED lights. So far I have built a few display signs for indoor applications, where one microcontroller is connected to a number of RGB Led ...
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72 views

Led Matrix multiplexing: sinking/sourcing current + LED brightness

I am trying to make an 8x8 LED matrix (actually a bigger one, but for now it would be easier to discuss this more simplified version) and I have gotten too confused about a few things concerning the ...
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Wiring a 28 segment LED bargraph (to an Arduino)

I need to control a Barmeter 28 led bargraph via an arduino (Mega). I believe I have found the details of the component here: http://www.barmeter.com/download/bl28-3005sk04y.pdf (BL28-3005SK04Y) I ...
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97 views

Why can the IS31FL3731 only handle 32 RGB Leds when it can handle 144 Regular ones?

I am looking at using the IS31FL3731 IC in a project soon, but I am confused as to why the data sheet says that the circuit can only use 32 RGB LEDs when it can use 144 regular LEDs. The data sheet ...
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73 views

LED matrix - MOSFET driver leakage?

I have 4 common-anode RGB LEDs in a 4x3 matrix. I have a BSS138 on each of the red, green and blue cathode lines and a BSS84 on each of the anode pins. The power supply is 3.3v, which is close enough ...
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84 views

How to stop current leakage in LED matrix

I know that this issue has been discussed in this forum, but I am a beginner in electronics and I was unable to come up with a solution to my problem by reading the related threads. I am doing a 3x5 ...
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57 views

LED Matrix creation using resistors & MAX7219

I've been attempting to create my own LED matrix, but now I've plugged it all together I'm getting some unexpected LED's lighting up, it seems some are getting power when they shouldn't (not very ...
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1answer
55 views

LED on and off indicator for solenoid

I have a circuit with a single momentary on switch that causes a solenoid to change position. I need to be able to see which position the solenoid is in. I've looked at the circuits for motor control ...
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29 views

What could be causing an unreliable output for 3 different IS31FL3731 chips

I have a board that uses the Adafruit breakout of the IS31FL3731 to control 81 illuminated switches. I have some code that runs on an Arduino that should turn all the lights on, but only about half ...
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123 views

Multiplexed LED column driver MOSFET doesn't fully turn off without a resistor parallel to the LEDS

I have a board with a 16x10 led matrix. The columns are switched with DMG9933 Dual P mosfets. The rows are driven with a constant current led driver ST STP16CPC26 (similar to TI TLC5956) I noticed ...
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1answer
40 views

How will current divide in a LED matrix in one select line when there are 8 data lines?

simulate this circuit – Schematic created using CircuitLab Let's say I have a select line that is connected to 8 data lines in an LED matrix. The current at the drain of the MOSFET is 800mA. ...
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1answer
131 views

Led panel sending and receiving card working

I understand how a RGB LED panel is driven from sparkfun's explanation (here). From manufacturers like Huidu and Novastar I get that in a setup you often need a sending and receiving card. Like you ...
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118 views

Led driver high current and voltage

For a project I have to design a led beacon that will consist of +400 LEDS. These LEDS will be driven only a short amount of time maximum of 3% duty cycle (frequency: 100Hz, pulse: 300us). The LEDS ...
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213 views

How does a dot matrix led driver know the voltage of an led?

I wanted to make a 7x10 led dot matrix using two 5x7 led dot matrix from lite-on (LTP757KR). I first thought of using shift registers, then I found a 12 x 8 dot matrix led driver with a bunch of ...
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Why does a 74HC595N work in LED matrices?

I have checked a lot of LED matrices, and mostly a 74HC595N shift register is used. In some cases a TPIC595B like below. Example: Driving LED arrays with Arduino Circuit from above example: I ...
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366 views

Do I need to split my GND lines?

I am intending to make a multiplexed LED matrix, possibly with 16 rows, 8 columns. This means maximum 16 LEDs (one full row) will be lit at the same time, thus 16 LEDs * 20 mA/LED = 320 mA. According ...
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1answer
797 views

Library for driving P10 LED Display with ESP32

I am trying to make a 10 digit cricket scoreboard for which, I want to use P10 LED modules as digits. My objective is to change the score from Mobile Phone via BLE. ESP32 microcontroller suits best ...
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49 views

What is sitting inside LED array so that I can create my own drivers?

I have a LED array and an app to drive it: https://itunes.apple.com/US/app/id1431362600?mt=8 https://play.google.com/store/apps/details?id=com.yskj.led&hl=en_US I connect to WiFi and I'm able to ...
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1answer
317 views

LED Christmas lights without limiting resistor

My LED Christmas light strings do not have a series limiting resistor, how is this achieved? They are 70 LED strings with two 35 bulb sections. I have carefully checked and there are no provisions in ...
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240 views

Multiplexing LEDs

I’m doing a 16X32 LED matrix system. Controls via a PIC micro controller. The whole circuit is operating from a 5V source. For easy understand I have drawn a single Row/column how my hardware is ...
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70 views

Can I use an LDO to control several diodes at a speed in the order of kHz?

I wish to control the switching on and off of several LEDs as indicated in the following figure: simulate this circuit – Schematic created using CircuitLab The bases of transistors and the ON/...
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556 views

LED Fault in PCB - Some strings of LEDs intermittently dim

I have a university project that involves working with surface mount LEDs. For some reason, some of the rows of LEDs, when lit up, are dimmer than they should be. This problem is only intermittent ...
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2k views

How do I get 5V 10A output from a 3.7V li-ion battery for 64x16 led matrix display module?

Please I am new to electronics and new here. I'm doing a project which involves the use of a 18650 li-ion battery (or two as may be the case) to power a 64x16 led matrix display module which (...
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4answers
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Can I replace these many capacitors with just one?

I'm designing a schematic for an addressable RGB LEDs array and I've chosen the WS2812B because of how common and cheap they are. Looking at the typical application circuit, I noticed there is a ...
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1answer
95 views

How to protect LEDs from high voltage during NPN transitor transitions?

I am using a 555 timer and an NPN transistor to drive an array of 12 LEDs from a 9v battery, and a potentiometer to control the duty cycle. I am concerned about the voltages the LEDs will be subjected ...
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1answer
132 views

Gounding for EMI and signal integrity - LED Matrix multiboard design

I would like to implement a LED Matrix circuit like this one, where the LED matrix enclosed within the blue dots will be on a seperate PCB than the rest of the circuit. Since this will be a ...
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1answer
148 views

Dim a LED array through PWM on power supply or output enable?

I have an 8-LED array driven by an 8-channel source driver (TD62783AP) controlled from an 8-bit shift register (74HC4094). When it comes to dimming the LEDs using PWM, I came up with two solutions, ...
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2answers
316 views

Is it a good idea to refresh a display (8x8 LED matrix in this case) inside an interrupt handler?

Let's say I have an Arduino connected to a 8x8 LED matrix. In my case, the LED matrix is driven using two 74HC595 shift ...
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2answers
35 views

What is the correct current in the datasheet for the LED-Matrix?

If I understood correctly the maximum DC Forward Current for one LED is 30mA (Page 2). So if I wanted to drive an entire column (5 LEDs) I would need 5 times the forward current. If I don't take the ...
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1answer
71 views

controlling some RGB LED modules with HD74HC254P and 74HC595N ICs

I got some LED modules dismantled from old festival screen. It would be nice to get them working, but I can't find any info about them, neither I have any idea how to controll them. AFAIK they are ...
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1answer
77 views

Method for Sending Multiple (16) Channels of Duty Cycle Modulated Signal over Medium-Long Distance

Problem What is the best method or industry standard solution for transmitting multiple channels (13 signal, 3 ground) of duty cycled modulated signals up to 25 feet. The data will be transmitted by ...
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1answer
242 views

Power consumption of APA102c LED 10mm grid

I have two of these 16x16 grids (https://www.pololu.com/product/2533) with leds programmed to have white color (255, 255, 255) and brightness level = 16. I have a power supply with maximum of 16A ...
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1answer
94 views

What is a Data-to-Segment Delay (MAX7219)

My guess is how long the data takes to be shown as a segment/digit. Is that true? In the datasheet is says 2.35ms but I would need 1ms or below. Is there a faster alternative? Datasheet (Page 3 at the ...
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2answers
71 views

Transformer getting hot

I have build an LED array consisting of 75leds, 5 connected in series with a 39ohm-1/4watt resistor and 15 such series connected in parallel to the rectifier circuit having 2-IN5408 diodes and 1- ...
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2answers
67 views

Powering an LED matrix

I am building an led matrix having 75 SMD 2835 60mA leds. I am connecting 3 in series with a resistance and then connecting the 25 series parallely to a 12V power source supplying 3A@12V. This means ...
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1answer
118 views

Level translator for led matrix

What is the best way to make a level translator for a led matrix? I have an mcu port 3,3V 5mA and I want to replace the leds with higher voltage and current, 24V 50mA for example This is my led array ...
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2answers
2k views

Running MAX7219 at 3.3v with ESP8266?

I just got a 4 chained 8x8 LED max7219 displays with a 5 pinout, these are very popular https://www.amazon.com/Wangdd22-MAX7219-Arduino-Microcontroller-Display/dp/B01EJ1AFW8/ref=sr_1_5?s=books&ie=...
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8x8 LED Matrix has 26 pins

Recently I issued a 8x8 matrix from electronics club in my college (if thats what you want) without noticing the number of pins present on it. Everywhere on the internet, working of 8x8 is explained ...
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3answers
449 views

darlington transistor led matrix

I want to run an 8x8 led matrix by using a darlington transistor arduino and decoder. for some reference I was looking at this previous question(Darlington Transistor Array). Each of my Leds draws ...
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2answers
922 views

MAX7219 resistor value

I'm planning to build a few 8x8 LED matrix using 1,7/2,3V and 20mA LEDs, and for controlling them, I have purchased a PCB mounting a MAX7219 with an included LED matrix that you can easily detach. ...
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2answers
510 views

Calculating current for a parallel array of in-series LEDs

I am getting an odd reading from an array of LEDs, which I could do with a little help understanding. I have a very specific project, but to abstract this question from that, let’s assume the ...
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1answer
95 views

Can two MAX7219 chips drive a 10x11 LED matrix? [closed]

I want to drive a 11x10 LED matrix. Can two MAX7219 do this? Is there a way to have on MAX7219 handle a core of 8x8 LEDs and the other would drive the remaining 3 cols and 2 rows?
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1answer
199 views

AVR C 74hc595 rgb matrix multiplexing and brightness

I have built a test matrix 2*2 rgb LED's, common Anode. Connected the anodes into columns, and the Cathodes trough 220R resistors into R,G,B rows. Both go to two different 74hc595 shift registers. I ...
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2answers
809 views

Combine 2 outputs from a single powerbank to increase current for driving leds and controller

I want to power a led matrix of 256 leds and my controller on the road. I calculated an approximation of the required current for the leds at 5.1A and the controller at 0.1A making 5.2A @5v together, ...
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313 views

RJ11 pinout (serial) for Amplus AM03128-H11 LED display

I've got an Amplus AM03128-H11 LED display, without the documentation and serial cable. I found the programming manual online, but I have no idea what the pinout on the serial RJ11 connector is ...
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1answer
124 views

Arc welding near LEDs. is this a terrible idea?

I have a 16m x 0.8m grid of neopixel-based leds, ziptied to a metal grid of the same size (matrix of 8x120 LEDs). The LEDs have been waterproofed by inserting them into clear heatshrink, and a glue ...
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1answer
109 views

Led Matrix Driving Method

I am currently working on a led matrix display project. It is not prebuilt and it will be built it using individual leds. The size is 16x16. I have been searching about on how to drive the display ...
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4answers
532 views

How does LED matrix circuit work in the following example?

The circuit below shows how to build an LED matrix with shift register multiplexing. From what I understand, R1-R8 is the column vector setting the LEDs high or low and the shift register will pick ...
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1answer
105 views

WS2812B - Response time

I'm working on a project that needs some decor lighting, the lighting need to be able to render objects, so I was thinking of building a 32x16 LED matrix with WS2812B chips, and control it with a ...