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41 Threads found on edaboard.com: Led Multiplexing
It all starts with an ambulance and a need for really bright emergency lights. This is in Mexico so a three thousand dollar Federal Signal or Code 3 light bar is out of the question. I have to use the existing incandescent light bar and convert it. I've resolved the 30 watt,36 volt led chip heatsink issue. But I need to strobe 36 volt chips w
I doubt the led/transistor current is only 20mA because they are multiplexed. multiplexing causes PWM dimming so the peak current must be pretty high to make enough average current. As you can see from the specification for saturation, beta is not used when a transistor is used as a switch. Beta is used when a transistor is a linear amplifier with
Hello All, I am working on displaying day, date & time information on 7 segment led using 74HC595 shift registers and COMMON ANODE configuration. Please see my attached diagram. I am explaining the acrchitecture as follows: 1) The top row displays time in HH:MM:SS format. 2) The middle row displays date in DD:MM:YY format. 3) The lowest row
Hello friends i want to create 3 seven segment led drive using At89c51 micro controller ? how can i start ? and also i want to create using switch or variable POT to increment or decrement the digit . and is that possible to save last digit at device power off and after some time power on last value stored using external eepr
Hi, on first sight it seems ok. But the display seems to be an 4 x 7- segment led display. It is in multiplexing technique. Mind that the current on the digit wires (1, 2 , 3, 4) must handle max. 8 x led current. Now it depends on the led current if the AVR can source current. Also mind that with (...)
charliplexing. Switching ON one segment at one time. NOT ALL SEGMENTS. I'm working on hardware. I dont have proteus file right now. charlieplexing is not the same as (just) multiplexing segments, its purpose is to use as few pins as possible Looks like complicated way of doing things! 'Ch
I need hellp am trying digital clock using pic 16f877a interfaceing with rtc 1305 and seven segment leds please give source commend and how to flash pic using in circuit serial programing,......................
There are several things which may be wrong with your circuit: 1. You're trying to push around 40mA through each led segment. The power supply is 12V, the led segment drops about 1.2V, and the resistance is 270 plus 14 for the MOSFET...that's (12-1.2)/(270+14)=38mA. That is way too much. You should only need about 10mA. And with only 10mA yo
Are you sure of your power needs? 7-segment displays usually draw far less current than 3A at 30V, that's 90W ! Most led displays use multiplexing so only one digit at a time is actually powered up and they sequence fast enough that they all appear to be lit at the same time. Can you give more information on exactly what you are trying to achive,
Hi I wan't to control around 100 RGB led (not an led matrix) and need to obtain different colours. Now I am trying the multiplexing by switching the common anode of led using a ring counter and applying the 3 channel PWM from MCU. But for me, I cannot sacrifice the led brightness, I want maximum brightness. (...)
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One possible option is the use of a Port Expander or Shift Register. 6 Digits 7-Segment led multiplexing using a Shift Register The port pins of a PIC can only be configured as input or output, not bidirectional, however the direction of a port pin can be ch
You can see Dot Matrix 8x8 or led 16X8. This is for PIC, you can see the logic to multiplexing and shifting character.
The only drawback in your setup, if any is less brightness from led display which can be managed by using more current drive and using high brightness displays. Two 8 bit ports will be needed leaving enough i/o pin for doing rest of the job.
hi can anyone help me out to solve the issue in multiplexing 7 seg led using pic 16f83.... its a 10min timer counts from 0 00 to 9 59 i got output but the numbers are fluctuating... i attached code and proteus design file....
take a look at microchip application note AN529 it explains multiplexing the led displays, to use less i/o ports than you do ... it is for an older pic 16c54, but the principles are the same with a 16f877 just read the app note and you will learn how to implement your
hey! guys i wanted to use the timer 2 of 8051 to use it as the multiplexing delay for seven segment led display. So guys if anyone of u know how can i use timer 2 of 8051 please give the pseudocode or C code or assembly code will work too. thanks
hi , any one know how to write 4 digit 7 segment led display with multiplexing approach for pic18f2480 plz guide me regrads R.Anandaraj
There is no need to control both sides of led. Just use only one IC. +++
Hi, I'm building an led display from a group of 5x7 matrices. I'm building it in stages as I have got to grips with PIC programming, shift registers, multiplexing etc. My next challenge is understanding how to power it though, and I'm having no luck finding anything to help me on the web. I will be running about 10 5x7 matrices, lighting them a