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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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767 views

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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3answers
347 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
29 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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1answer
38 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
164 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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2answers
161 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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2answers
58 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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3answers
155 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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3answers
187 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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0answers
30 views

How to swap row/column index in switch matrix ? HC595/HC165 shift registers

I'm having some issue with an Arduino code to interface a 12x12 switch matrix and 12x12 LED matrix. The 12x12 LED matrix is an array of WS28xx and the switch matrix is a combination of HC595 / HC165 ...
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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
68 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
75 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
87 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
178 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
30 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
64 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
65 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
88 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
66 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
56 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
50 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
76 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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0answers
131 views

7x6 Bicolor (3-legs) LED matrix design with Arduino - Multiplexing with 4017?

I am currently trying to make a 7x6 LED array with bicolor (3-legged) LEDs. I am just planning to make it programmable (no scrolling, etc.) for making a Connect 4 game. Here is the current circuit ...
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2answers
738 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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2answers
159 views

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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0answers
178 views

How can I control a 64x32 LED matrix with a BeagleBone Black?

I'm a mechanical engineer looking to include a 64 x 32 RGB LED matrix into a mock up door trim (automotive). I purchased a BeagleBone-Black-Rev-A5A-1Ghz-512MB-Embedded-Computer-Onboard-2Gb-eMMC-Flash,...
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3answers
285 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
375 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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0answers
54 views

Run two power supply 5v 10A to control 6 RGB 32x32 Led Matrix

I am controlling 6 32x32 RGB Led Matrices with a Raspberry Pi. Each Matrix is rated for 5V and up to 4A. However, for the images I am displaying, the 6 panels rarely go above 5A in total. And as such ...
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2answers
219 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
77 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
127 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
341 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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0answers
192 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
106 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
84 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
279 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
63 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 ...
0
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1answer
546 views

Led matrix 64x64 1/32s HUB75 with only A, B and NC lines

I am trying to drive a led matrix, a RGB 64x64 with a HUB75 connector, 1/32 scan, with 2 RGB lines (R1G1B1, R2G2B2), a latch pin, a clock pin, an output enabled pin, and 3 pins I don't know how to use ...
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1answer
69 views

controlling many LEDs on an individual basis

Similar to this question here: Hooking up multiple RGB LEDs while using a minimal number of PWM pins on an Arduino? I want to control about 800 rgb LEDs (800x red signals, 800x green, 800x blue), ...
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1answer
60 views

Commond anode led driver

I need to drive a bunch of 7-segments and 14-segments led display (in total, 105 LEDs with common anode). I bought an HT16K33 to drive them, but did not take into account the common cathode ...
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2answers
417 views

8x8 LED Matrix re-build

the company i work for has tasked me in rebuilding an old LED sign we had replaced. (newer led rgb version) The driver board that was in the sign has gone out. So i am trying to rebuild the driver ...
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0answers
75 views

Reading multiplexed or charlieplexed display, is it possible and how?

What I try to do is reading a 7 pin display with 35/36 segments/LEDS. I want to do this to know what the device is doing. Why? Because I want to know I can do it (it is possible anyway) and to be able ...
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1answer
128 views

Is it OK to drive a LED matrix with constant current?

I bought one of these LED matrix modules as described in this Adafruit PDF: https://cdn-learn.adafruit.com/downloads/pdf/32x16-32x32-rgb-led-matrix.pdf The PDF says "they do not have built in PWM ...
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1answer
257 views

8x8 RGB LED PWM matrix with TLC5947 which IC to use on the cathode end?

I made a simple LED matrix with shift registers in both row and col(anode and cathode). Now I want to build a 8x8 RGB PWM matrix so that I can control the color of each LED in the matrix. One thing ...
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3answers
106 views

Loading a shift register without displaying its contents/output?

I'm making an LED matrix using two DM7495N 4-bit shift registers and one 8-bit shift register. The 4-bit registers are for the anode columns and the 8-bit connects to transitstors controlling the ...
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1answer
127 views

Battery powered RGB matrix board

I'm not sure if this is the best place to ask this but I'm not sure where else too For my graduation I'm trying to embed a Led RGB matrix display connected to a raspberry pi on my cap. Iv seen this ...
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2answers
83 views

Convert logic signals to be able to supply/sink higher currents [closed]

I am making a LED matrix and have the required logic in place to drive the unit. My problem lies in the fact that my matrix is 80x56 diodes large and requires a fair amount of current. Each diode is ...
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1answer
356 views

How to interface matrix LED with beaglebone black

I'm a newbie to electronics and for my project I need to control a matrix LED with beaglebone black. I bought a LED click board (https://download.mikroe.com/documents/add-on-boards/click/4x4-rgb/4x4-...