Questions tagged [multiplexer]

A multiplexer selects one of two (or more) inputs based on a control input. It then outputs the selected input.

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26
votes
15answers
26k views

Controlling 500 LEDs with PWM

I'm considering taking on a project that would involve individually addressing 500 LEDs, optimally with PWM support for each. I'm planning on using an Arduino since I already have one, but I'm open ...
26
votes
3answers
32k 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 ...
17
votes
9answers
3k views

Reading a huge number of analog sensors in real time

I'm trying to build a MIDI-like controller that has a neck like a guitar. On that neck, there is a huge matrix of pressure sensors. The controller will emulate 3 strings. The way this works is: ...
17
votes
2answers
6k views

Is Multiplexing ever superior to Charlieplexing?

I've reviewed the two methods, and multiplexing really only appears to have one advantage, that it would be easier to track down a failed LED than in a Charlieplex array. Can someone more ...
11
votes
1answer
823 views

Why two inverters cascaded in multiplexer control signal terminals?

Why cascaded inverters are used in the multiplexer when it is possible to realize the circuit using a single inverter.
10
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6answers
19k views

How can I control many LEDs with just a few pins on my micro?

I am using an Atmel ATtiny13 which has a 6-pin I/O. I'd like to control about 15 LEDs but am unsure how to connect everything. Without multiplexing of any sort, it seems I'd only be able to control 6 ...
10
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6answers
6k views

Large Multiplexers/Data Selectors

I'm looking for a multiplexer IC with 128:1 or more inputs (256 would be quite nice). I would have thought such a device would be quite common yet I'm having a tough time locating it. It could be that ...
10
votes
7answers
30k 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 ...
10
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2answers
2k 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 ...
9
votes
4answers
5k views

How can 16 buttons be connected with only 8 wires?

Here is the product. I understand the idea: these 16 buttons use a 4x4 matrix. 4 lines for rows, 4 lines for columns, and we have 8 cables. But: How can this work without any multiplexer ? Can this ...
8
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9answers
3k views

Serial control of 25 LEDs from a single pin

I have a microcontroller with one available digital pin. How can I control 25 LEDs?
8
votes
6answers
854 views

Controlling 5000 LED

I'm doing a project where it requires to control 10,000 I/O. 5000 output - For 5000 LED, where only 1 LED will be light up at one time 5000 input - For 5000 sensor, where it'll sense the presence of ...
8
votes
3answers
4k 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 ...
8
votes
3answers
36k views

How do you implement the following function using nothing but 2:1 MUX?

I am having difficulties understanding how to implement boolean functions, particularly given that I may only use 2:1 muxes and the variable D as a residual variable. The function is as follows: $$ ...
8
votes
3answers
3k views

Use of tristates vs multiplexers in a RAM

Why are tristates favored over multiplexers to select the output from RAM? The explanation that I've heard of is that the RAM is too large for using a multiplexer but I need more details. A theory we'...
7
votes
3answers
9k 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 ...
7
votes
2answers
738 views

What is the purpose of diodes in flip-dot displays?

In most flip-dot displays i've seen, the electromagnets have a set of two diodes connected to them. This is also mentioned by David, who asked a question about the displays before. However, in the ...
7
votes
2answers
946 views

Slow PNP turn-off time, how to optimize it

I'm multiplexing a pair of Nixie tubes. The high-side control is done with two pairs of transistors, MPSA92 high-voltage PNP to switch the 160V to the tubes, and a BS108 to control the base of the PNP:...
6
votes
7answers
11k views

Multiplexing Inputs on a microcontroller

I have a 4 way DIL switch that I use to provide input to a microcontroller, and I need to free up a port to use for something else. Is there a way to multiplex 4 inputs into 3 microcontroller ports? ...
6
votes
6answers
1k views

What's the maximum number of outputs you can control from a microcontroller with n outputs?

Been pondering this for a while, and I think it's \$2^{(n-1)}\$ outputs. If I have 5 outputs, I'll use 1 as the signal, and the other 4 as control lines to cascaded decoders, which gets me 16 outputs....
6
votes
4answers
14k views

Difference between Multiplexer/Demultiplexer and Analog Switch

What (if any) difference is there between mux/demux IC's and analog switch IC's? I'm comparing this in the context of chips with the same IO lines (for example a 1:2 or 2:1 mux/demux vs. a SPDT ...
6
votes
2answers
2k views

Multiplexing, Animation, Bitmap coding on MCU. How to do it right?

I have been recently getting into programming and micro controllers. I found myself that i don't really know how to do multiplexing, animation, easily displaying pictures on LED display. I have been ...
6
votes
3answers
865 views

Analog Mux as Cheap I2C Mux?

Just looking to have two devices on a single bus with the same address. There are many I2C multiplexers available, but they seem to cost ~4x what a 2x 2:1 analog multiplexer costs. Any reason I can't ...
6
votes
3answers
8k views

Analog Multiplexer?

I am almost completely new to electronics. Recently I was reading about an 'analog multiplexer' I know what a multiplexer does, and how it works, but is there such a thing as a 'digital multiplexer' ...
6
votes
1answer
766 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
votes
1answer
2k views

Controlling a MOSFET with a microcontroller

I'm trying to use a p-channel MOSFET (FQP27P06) to multiplex four large common-anode seven-segment displays. I'm using a TPIC6B595 high voltage high current shift register to sink the segments for ...
6
votes
2answers
3k 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
10k 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 ...
6
votes
2answers
2k 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 ...
6
votes
1answer
5k views

What is the difference between an analogue multiplexer and digital multiplexer?

As far as I know, analogue multiplexing is used to take voltage samples from many channels in a short time. It passes the voltages from an input to the ADC without amplifying them. I guess buffer them?...
6
votes
2answers
2k views

How can I use one microcontroller to increment/decrement 4 sets of LEDs using 8 push button inputs?

I want to design a very small project for a portable score keeper. It consists of using one microcontroller to control 4 sets/groups of LEDs on a small PCB. It is a very small scale project (3.5in X 1....
6
votes
3answers
9k views

Multiplexing LEDS and Multiple Output Pins

Ok.....i've been trying to understand something (and trust me, to most people it's a VERY newbish question) So I see people all the time "multiplexing" LEDS. using just a few Pins. Lets say for an ...
6
votes
4answers
2k views

Multiplexing a Circuit

Frankly, I'm overwhelmed with this circuit that I have to start building in lab tomorrow. Last week we built an octal decoder that takes a 3-bit binary input from 000 to 111 and displays a unique ...
6
votes
2answers
2k views

Multiplexed Thermocouple Considerations

I have a side-project to read temperatures from 4 thermocouples (K type, around 500F for coffee roaster data logger), and no previous analog experience at these levels. I've identified two possible ...
6
votes
2answers
500 views

Minimizing(optimizing) digital logic circuit with multiplexer(s)

(this by the way was an exam question) For \$F = \sum m(2, 3, 5, 7, 11, 13)\$, I am trying to implement a digital logic circuit using only the following: 2:1 MUX (cost: 12, and must use at least one ...
5
votes
5answers
7k views

Is an ALU a multiplexer?

I'm studying digital electronics where the components ALU and multiplexer appear. To me the ALU seems like a multiplexer but it's not specifically mentioned that this is the case. Is it so, or why not?...
5
votes
7answers
5k views

How can I control 128 (or more) solenoids?

I need to switch 128 solenoids either on or off individually, several times a second. I'd like to drive this from either a PC, or an embedded device. How would you recommend I do this? Perhaps ...
5
votes
4answers
544 views

Making an ID of a board type

I want to make hardware ID of a board without using microcontroller or any kind of pre programmed eeprom. All boards of same type will have the same ID. One ID per board type. I was thinking of using ...
5
votes
5answers
9k 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
votes
3answers
2k views

What shift register ICs am I looking for?

I'm designing a project that requires far more I/O than a typical microcontroller offers. No problem, right, just use shift registers and stuff. Wait nope, why am I having problems? I'm planning on ...
5
votes
1answer
775 views

How do “beyond the rails” analog switches work?

I'm familiar with using CMOS switches ("transmission gates") for switching analog signals, but you can't use them for switching voltages beyond their supply rails. (So if you have a single supply ...
5
votes
1answer
402 views

What does a 'full 18×16 barrel shifter' mean?

My practical textbook asks me to design a full 18×16 barrel shifter on paper. I have tried looking around but cannot seem to figure out what the A×B convention means when describing a barrel shifter. ...
5
votes
2answers
2k 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 ...
5
votes
2answers
2k views

Using the raspberry pi to measure multiple electrical circuits

I am looking to use the raspberry pi to measure the power consumption of multiple household electronics and record the information to analyze later on. However, I'm not sure if it's possible to ...
5
votes
1answer
422 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) ...
5
votes
1answer
623 views

Over voltage and reverse voltage protection of multiplexed ADC with voltage follower

I am designing a protection circuit for the ADC section of a design I am working on. There will be 8 analog signals being read by a single pin of the MCU via an 8 channel multiplexer. The analog ...
5
votes
2answers
1k views

In search of a component or device that switches multiple lines based on input selection

Okay so the foundation for my curiosity is that in dealing with Arduinos, I found they can be used to program the similar but smaller ATtiny chips. This is the main hookup configuration that some of ...
5
votes
2answers
2k views

Methods to drive a multiplexed LCD with logic-level signals?

I've used such a technique in a couple of the products I've designed, but I've never seen anyone else do so. It's possible to drive a 3-way multiplexed LCD using a bunch of 74HC595's to generate an 8-...
5
votes
2answers
3k 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 < ...
5
votes
1answer
278 views

Multiplexer for low-voltage measurements

How does voltage leakage (or cross-talk) from a mux affect low-voltage (voltages on the range of 10s of microVs to mVs) measurements? I am building a measurement set-up consisting of a Keithley 2400 ...