A multiplexer selects one of two (or more) inputs based on a control input. It then outputs the selected input.
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2answers
76 views
How does this circuit multiplex an antenna between a transmitter and receiver?
I've built a Softrock RXTX kit (full schematic: pdf gif, see lower-left corner). It has one connector for one antenna used for both receive and transmit, but I don't fully understand (likely due to my ...
3
votes
1answer
66 views
32 bit, 4 way multiplexer
I'm relatively new to electronics and recently decided to design and build a very simple CPU as a personal project. My instruction size is 32 bits and I want to have 32 bit registers so I am going to ...
1
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1answer
29 views
Sample and Hold
When we have a data source oscillating at a frequency of say 4KHz , this implies that the Nyquist sampling rate would be at least ...
1
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1answer
54 views
Multiplexing with or without transistors
I'm doing something in where I need to multiplex 6 7-segment displays. About doing it, I found things like this:
And things in where the same thing is done without the transistors, just by ...
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1answer
63 views
Concept of Time Division Multiplexing [duplicate]
I have been studying the concept of Time Division Multiplexing, but I have not been able to understand some stuffs, for instance, I have not been able to understand why the sampling rate for audio is ...
2
votes
1answer
96 views
Multiplexing large LED matrix
I have a project which involves building a 64 x 48 (3072) LED matrix driven by a Raspberry PI computer. I am a first-year computer engineering student so I am still inexperienced with shift registers ...
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1answer
122 views
Time Division Multiplexing question [closed]
I am new to the concept of Time Division Multiplexing in school, after reading a few books I came over this question.
With the help of sketches explain Time Division Multiplexing (TDM) in terms of ...
1
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2answers
63 views
Arduino multiplexing help needed.
Is it possible to use an 8 output demux to switch between seven 16 output demux's in the case that I want to control several LED's with an arduino uno? Is there a better way to do this?
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1answer
33 views
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1answer
67 views
Finding the no. of decoders required in cascading
I am trying to solve the following question.
How many 3 to 8 decoders with an enable input are needed to construct
a 6 to 64 line decoder without using any other logic gate.
I have a Digital ...
13
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2answers
22 views
How do I extend the number of analog (input) pins available to me?
I already know how to extend the number of digital pins on an Arduino using a multiplexer.
I want to increase the number of analog input channels that I have. One solution is to add another Arduino ...
0
votes
2answers
70 views
iCMOS analog switches and multiplexers
Does anyone have any experience with Analog Devices iCMOS high voltage analog switches or multiplexers like the ADG1434 or ADG1411?
The specs for iCMOS sound very impressive. But they've been ...
0
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3answers
116 views
Connecting more than one serial device to PIC16f877a
In my project i need to interface a gps receiver and a gsm modem to pic16f877a, But there is only one set of UART lines in this Microcontroller. Is it possible to multiplex these two devices using ...
0
votes
1answer
60 views
Getting Strange Readings From a Multiplexer
I'm trying to build a simple gamepad controller to learn more about multiplexers (in this case a SN74LS251. This is how I'm wiring it:
And this is the code I'm using to get the button states:
...
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1answer
141 views
Learning Multiplexing with LEDs, transistor switching speeds
I am working with some friends trying to multiplex. The issue we run into is we aren't sure if we are hitting a limit on transistor switching speeds.
I am unsure if this is a hardware or software ...
0
votes
1answer
101 views
4 bit mux input/outputs
If i have a 4 input mux with the output being in the form of
S1 AND NOT(s0)
MY truth table therefore looks like the following (remember NOT(S0)).
...
3
votes
2answers
87 views
Is upping the voltage on a multiplexed LED display an appropriate response for dimness?
I have a 10 character x 16 segment display that I'm driving using multiplexing off a PIC. The problem is, however, that with each display only being on 1/10th of the time, the display appears much ...
0
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1answer
68 views
multiplexing 16 sensors
I need to read 16 color sensors(TCS3210) one after another. So I am thinking of connecting all the outputs to a single atmega32 i/o pin and selecting a sensor using a demux showing low on the output ...
1
vote
1answer
86 views
Maximum LEDs on a matrix
There are several methods to drive LEDs using a microcontroller. The easiest method is just connecting all LEDs to an own pin on the microcontroller. Say you have \$n\$ pins available, you'll be able ...
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1answer
324 views
Design a 4:1 MUX by three 2:1 MUX or by 2:4 decoder? [closed]
A 4:1 MUX can be built by using three 2:1 MUX. But I've not done it this way: I've used a 2:4 decoder to make a 4:1 MUX. Does it matter?
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1answer
265 views
Multiplexing an 8x8 Matrix - Why Transistors?
I'm trying to understand how to properly multiplex an 8x8 matrix (or any large amount of LEDs)
http://arduino.cc/en/Tutorial/RowColumnScanning
However, I'm getting a bit confused, since I've found ...
0
votes
1answer
127 views
Using Open drain to get +5V
I have a legacy board in my product that has 1 temperature input with 2 rtd temperature probes.
Until the new boards are ready the manufacturer has used a relay already mounted on the board to switch ...
8
votes
2answers
412 views
LED Multiplex Anode-Row Driver
I'm helping build this art installation that amounts to a large 16 x 16 pixel display. I settled on using 16 TI TLC5926 constant current driver chips chained together to give me direct drive to each ...
0
votes
2answers
197 views
Designing a good RF Transmission/Reception system for Embedded System
I want to have 4 sensors transmitting information to a microcontroller ie
4-bit Encoder -> Transmitter >>>>>>>>>>>> Receiver - > Decoder -> MCU
The problem I have is that if I use 4 transmitters and ...
2
votes
2answers
321 views
MUX verilog code
Can anyone explain the difference between the two codes below. Both written in Verilog, Xilinx. If someone can explain how the second one works would much appreciate it.
...
2
votes
3answers
161 views
Best way to build a 64-bit output multiplexer
I'm looking to create something to multiplex N 64 bit signals together. The goal of the project is to provide digital switching between a library of old cartridge based video games.
Essentially I ...
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1answer
182 views
Implementing a shifter with only multiplexers
This is my homework question, I would appreciate any hints to help me get started.
A shifter is used to shift a string of 0's and 1's to the left or
right by a fixed number of positions. The ...
6
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3answers
902 views
Miniature Traffic Light with Raspberry Pi: Wiring many LEDs
Background:
I am a Civil Engineer specialized in traffic control devices and I have a small hobby project to build a scale model traffic light system. I can manage and control the traffic light ...
1
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1answer
153 views
Assigning ports of an n bit multiplexer
I have ONE n-to-1 multiplexer and I'm trying to assign its n input ports from another component which has n output ports. How can I do this?
My code is given below, and the errors.
I've ommitted ...
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4answers
123 views
How do I multiplex many signals into my sound card?
I'm looking for a recipe that will allow me to...
Hook 24 piezos to a box that will "multiplex" their output into a single signal that I can connect to the microphone input on a PC soundcard.
The ...
1
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2answers
89 views
LCD Multiplexing: Segment Off Voltages
I am reverse engineering a LCD (this is a raw bit of glass, i.e. no controller) and trying to understand the signals... there are 16 lines of which 4 are backplanes and 12 are segment lines.
The ...
2
votes
2answers
605 views
What is the minimum number of NOR gates needed to implement a 2-input multiplexer?
In the first chapter of The Elements of Computing Systems, the reader is asked to implement basic logic gates like Not, And, Or, Xor, as well as a 2-input multiplexer and de-multiplexer. The authors ...
0
votes
1answer
80 views
Building an 8 to 4 Encoder from a 8 to 4 Multiplexer?
I have a a 8-to-4 Multiplexer ICs (MM74hC4052N) and I want to use it as a 8-to-4 encoder or 8-to-3 encoder.
Is that possible? If it is, can drop me some hints on how to do that?
At one glance, I ...
2
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2answers
121 views
Is it bad design to use logic gates for multiplexing?
I have a PIC18F4550 which uses the same pin for UART RX and SPI data out.
Would it be bad design if I used a GP I/O pin and a logic gate to control the multiplexing of that pin?
When the IO1 pin ...
4
votes
2answers
581 views
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
votes
3answers
569 views
Best way to control 130 - 140 LEDS with Arduino Uno 32/64 bit led drivers?
I am new to electronic prototyping and had a few questions.
I need to control 132 LEDs individually. I want to make 3 rows ( 2 rows of 60 and 1 row of 12) I think i can matrix them but i would still ...
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votes
2answers
225 views
How to implement a 2-to-4 mux
Our logical circuit teacher asked us to draw the diagram of inside a 2-to-4 multiplexer and said it's going to be in our final exam. How is this circuit possible? I thought a mux always goes from a ...
0
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2answers
237 views
Multiplexer + flipflop all in one?
As you know if you have a 4 bits multiplexer, if you input 0101 the output 5 goes high, but right when you input another thing like 0001, output 5 goes low and output 1 goes high.
I need the ...
0
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0answers
401 views
How to Fix Multiplication Circuit using Logisim
I am designing a circuit that multiplies 2 bit 2's complement numbers.
The circuit uses Full Adder to add and Multiplexer to multiply and ALU for arithmetic.
I need feedback on whether the ...
4
votes
1answer
97 views
Can you pass resistance through analog mux?
I have a digital potentiometer that I want to calibrate by sending in my commands and then measuring what the actual resistance is. However, the resistance from the digital pot is (obviously) ...
3
votes
2answers
162 views
Differences between a FET multiplexer and regular digital multiplexer?
I need a MUX 8-1 with a very fast propagation delay; <10ns. I was searching Digikey and found a category of digital muxes called FET multiplexers, and their propagation delay is insanely fast < ...
1
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2answers
130 views
Mux for ultra low noise pre-amplifier
I am searching for a method for multiplexing 3 DC voltage sources (each ±10V p-p) to my ADC pre-amplifier circuit.
My requirement is that the multiplexer should not inject excessive noise into ...
1
vote
1answer
66 views
Multiplex two displays or use a higher pin count uC?
I am currently learning to program a NXP LPC1347 for a project which will utilize two SSD1963 controller-based displays. The issue is that the uC only has 51 IO pins whereas the total pins of the ...
2
votes
4answers
442 views
Multiplex dip switch input to microcontroller
I have 3 DIP switch packages with 8 switches each, and not enough inputs on my microcontroller. This article (you have to download the pdf to see the schematic) gives an example of what I want to do.
...
2
votes
1answer
861 views
Multiplex Seven Segment Display Fast enough to make Solid
I have been trying to multiplex a 4 digit seven segment display on my FPGA board but have been running into not being to get it fast enough so it looks solid to the human eye.
You can see an example ...
2
votes
5answers
980 views
How do I control several hundred individual leds with Arduino(s)?
I am working on an electronics project which involves hundreds of LEDs. (Talking upwards of six to seven hundred LEDs...a lot, I know.) Is there any way to control this many LEDs with one or a couple ...
0
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1answer
134 views
Optical switch for visible light from multiple endoscopes
This may not be a total fit for the electrical engineering exchange, but its a pretty specific hardware related technical question.
I am interested in multiplexing visible light optical fiber ...
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1answer
206 views
Looking for a 24vac switch from 3v inputs
I'm really new to building electronics, so please forgive my ignorance.
I'm looking to be able to supply 24vac (~.5A) to one of 16 outputs using 4 3.3v, 50mA inputs.
(Edited) The 4 3.3v inputs are ...
3
votes
5answers
2k views
Multiplexing two 7-Segment displays (Ghosting issues)
I am currently working on a simple scoreboard using two 7 segment displays, a shift register (74HC595N), two PNP transistors (2N3906) and an arduino uno.
Each 7 segment display is common anode, ...
5
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2answers
712 views
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 ...
