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
83 views

How to Design a schematic for 8-LED Logic Circuit and Turn them on in pairs? [on hold]

I'm trying to design the schematic of an 8-LED logic circuit and turn them on in pairs according to the following sequence: 1 - 8, 2 - 7, 3 - 6, 4 - 5, 5 - 4, 6 - 3, 7 - 2, 8 - 1 ,i used ...
0
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4answers
165 views

How to implement 8-bit 2:1 multiplexers on a PCB?

I need to implement a 2:1 multiplexer for 8-bit data. That is: as inputs it should take two 8-bit numbers and a Select line; and as output an 8-bit number. I could use two 74HC(T)157s (this is a quad ...
1
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1answer
55 views

Mutually exclusive headphone and speaker

I have a device that has only one set of analog audio out signals that are amplified for headphone usage. I want to be able to use these signals to output to a set of speakers OR a headphone jack, but ...
2
votes
1answer
165 views

A circuit having 2 inputs and 2 outputs

I am going to design a circuit that should have 2 inputs and 2 outputs. when both inputs are low both outputs should be low when input 1 is high and input 2 is low, output 1 should be a square wave ...
1
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3answers
141 views

How to switch between two input lines based on a digital pulse

How can I switch between two inputs based on a digital signal. I would like to have the Input 1 connected to the Output for the duration of the pulse and Input 2 connected to Output when the signal ...
0
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3answers
48 views

SN74HC138 demultiplexer. How do I implement a switch?

I have this demultiplexer and I need to configure it in such a way that I can control 8 transistors using its outputs. They NEED to be NPN transistors, so when I select an output using the addresses, ...
0
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2answers
145 views

Determine the Number of Transistors Needed to Build CMOS circuit

I would like to determine the number of transistors that will be used in the CMOS circuit below. Is there a specific formula for it?
0
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2answers
33 views

Multiplexing buttons using shift register - high impedance output

I have experience with 74HC4094, and I believe the 74HC595 is essentially the same - the datasheet says they have "tristate output", but that is only when OE is low - then all pins are tristate. What ...
0
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1answer
87 views

How do I find the Truth Table for Mealy State Machine?

This is a followup to my previous question: I have this assignment in college: You are to design a Mealy state diagram for a safety device. Assume that two debounced push-buttons, A and B, are ...
0
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1answer
81 views

Mealy Safety Device with 2 inputs

I have an assignment in college and I would like to ask some questions: You are to design a Mealy state diagram for a safety device. Assume that two debounced push-buttons, A and B, are available ...
0
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3answers
79 views

How to adjust red brightness on MAX7219 with RGB LED

I want to use MAX7219 (datasheet) to control bunch of RGB LEDs. With common anode LEDs I should be able to use up to 16 3-color bulbs in following configuration: simulate this circuit – ...
0
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1answer
81 views

Mealy machine to detect sequence of 2 inputs

I have the following assignment for a project at college and I have a few questions regarding it. You are to design a Mealy state diagram for a digital lock. Assume that two debounced push-buttons, A ...
0
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0answers
50 views

pin connection added

I am trying to communicate 24 hall sensor via arduino & 8:1 Mux . I am using CD74HCt4051E 8:1 multiplexer. Instead of hall sensor i have used potentiometer 24 nos and connected to MUX IC devide ...
0
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3answers
181 views

Audio Signal Switching - “DPDT switch vs. 4066”

I've got a signal coming from an electric guitar and I need to switch it. Basically it's a distortion circuit. I need to switch between the distortion and clean (directly connected to the output) My ...
0
votes
1answer
56 views

PIN selecting problem over arduino

My schematic as below. I have connected 8 hall sensor as shown in picture. Problem i am facing here is SO, s1, s2 The Led light are not glowing .Even the forard voltage across is 3.9v. i have tested ...
0
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1answer
59 views

Implementing F using a demultiplexer and an extra AND gate

Use a 1-to-8 Demultiplexer and an extra AND gate to create the function: F(x,y,z) = ∑m(1,3,5) If I were using an OR gate I think this would be trivial, simply put the 1 3 and 5 ...
0
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1answer
69 views

Multiplexer CD4067 bug:signal appears in unselected channels

I connected a multiplexer CD4067 with arduino. I will select ch0-ch15 in turn and pass the selected channel to A0 on arduino to do AD Convert. Then I only connected ch0 to 5V on arduino and selected ...
0
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0answers
74 views

High-voltage seven segment LED display driver problem

I've a circuit similar to THIS project, with a 74LS04 as inverters instead of 74HC54 (tested 74HC04 and CD40106 too) and ULN2003 instead of ULN2803. The circuit seems to work perfectly but when I turn ...
1
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2answers
133 views

Multiplexing problem with Arduino, MAX7219 e BJT

I tested the circuit below with an Arduino UNO, a MAX7219 and BC338. The sketch in Arduino is a chaser, so the leds should turn on in sequence. It consist of 7 segment (A-G) and two Digit (0-1). The ...
2
votes
1answer
63 views

A circuit that outputs one input voltage by default, or another if it is present

I'm trying to come up with a simple design that will take two analog inputs voltages (~0.2-1.6 V each). One is an "internal" voltage and should always be present. The second "external" input can be ...
0
votes
1answer
112 views

i2C multiplexer to use multiple sensor of the same type

I would like to hook up multiple sensor of the same type (temperature, pressure and so on). The problem is that each sensor can only have 2 different unique values for the register, so can't put more ...
1
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2answers
92 views

How does one implement the following function with these tools provided?

Suppose I have a function defined as follows, such that it is expressed in POS form, with the product of the following max terms of 4 variables (A,B,C,D): 0,3,4,7,9,10,12,15 and I only have a 4 to 1 ...
1
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1answer
51 views

Can avrdude address individual usbtiny programmers?

I'm envisioning a panel programming jig. In my mind, it consists of a Raspberry Pi, a powered USB hub, and a collection of usbtiny clones each connected to a pogo jig and a target on a panel. The ...
0
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1answer
232 views

Custom built 16x32 (40) LED Matrix controlled by Arduino

I am planning to build a clock / thermometer / info display. I have ordered 10 pieces of 8x8 LED matrixes from ebay (http://www.ebay.co.uk/itm/331064583297). As this is not a pre-built one I have got ...
0
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0answers
30 views

MAR /MBR / MUX Device

How can I modify this circuit to permit loading of the MBR from either the hex keyboard or from memory. As it is, the circuit can only load the MBR from user input.
0
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1answer
69 views

3 State Shift Register with 2-to-1 multiplexers

For a homework assignment I need to Redesign the right-shift register circuit of Figure 12-10 using four D flip-flops with clock enable, four 2-to-1 MUXes, and a single OR gate. The figure ...
0
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1answer
83 views

Strategy for up to 40 ADC inputs using alert feature

I'm working on a project where I want to monitor 40 phototransistors (IR breaker beams), but without having to constantly poll the ADCs. Ideally I'd want a digital pin pulled when one of the beams is ...
2
votes
2answers
161 views

Is it possible to drive a 4x4 RGB common-cathode LED matrix with a MAX7219?

The MAX7219 (datasheet) is a LED matrix driver that's designed to drive an 8X8 single-colour LED array. tronixstuff has an intro on how to use it with an arduino that has some relevant diagrams. I'm ...
0
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1answer
67 views

Transistor Isn't Forming the Connection

I have wired the following diagram. simulate this circuit – Schematic created using CircuitLab My understanding of transistors is relatively poor, and thus I am assuming it has to do ...
-1
votes
1answer
102 views

How to increase current output of a multiplexer for activating a relay

I want to make a multiplexer for my project which needs 24v dc to operate. I am using an OR Gate IC for generating an output. My 4 gate inputs are connected to 6V battery power and I am getting a 6V ...
0
votes
2answers
109 views

Shift registers(?) failing after being left on a while

Resolved: SLCLR on SN74HC595 was not tied to VCC, so behavior was inconsistent. I have a custom built board that is running seven 7-segment displays, multiplexed using SPI from an 5v Arduino Pro ...
0
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2answers
50 views

How are the Intersymbol Interference and Symbol Time (duration) related to each other?

In a lecture slide I noticed that OFDM(Orthogonal frequency-division multiplexing) mitigates the problem of Intersymbol Intereference over wireless systems because the symbol time is increased, in ...
0
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1answer
82 views

Circuit design for short-circuting outputs when needed

I am working with two sensors with 4 pin as output. My question is simple: I want to make circuit that allows me to short circuit the output of either one of the sensors individually when needed. ...
1
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3answers
161 views

Driving 60 signals one at a time, in constant sequence

I have an application where I need to turn on/off one of 60 signals one after another in a constant order, ever repeating. (1, 2, 3, ... 59, 60, 1, 2, ...) Only one signal is on at any given time. The ...
6
votes
6answers
853 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 ...
2
votes
2answers
252 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 ...
2
votes
0answers
194 views

What's up with my 74HC4052?

I am using a TI 74HC4052E to multiplex a TTL UART on a Microchip PIC32MX695F512 microcontroller. The expected behavior is for the TX and RX signals to pass through the switches unaffected; sadly ...
0
votes
0answers
99 views

8 IR sensors and 74HC4051 multiplexer where to place low pass RC filter?

So I've got 8 IR sensors like these Then I connect them to multiplexer. And arduino will run mux's selectors through the loop.. Something about 5-10 times per second(read every sensor 5-10 times ...
0
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1answer
105 views

Multiplexer CD74HC4051, always giving a true out

I'm testing a multiplexer from Texas Instruments (CD74HC4051). Both +5V and Ground rails are connected to the Arduino Duemilanove board. I've got a +5V signal in the channel A7 (pin4) and A0 (pin ...
0
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2answers
73 views

Multiplexer CD74HC4051, connections and parameters

I'm testing a multiplexer from Texas Instruments, below is shown the cabling I've done. But varying the select pins(9,10,11) has no effect, nothing happens. The LED always stays on. Vcc is 5v ...
0
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1answer
229 views

Arduino HC-SR04 sensor through CD74HC4051E multiplexer using single wire

I'm trying to get distance using HC-SR04 sensor and arduino. I've connected together Trig and Echo pins on the sensor, then it goes to port A7(pin 4) of multiplexer(selectors configured as follows: S0 ...
0
votes
0answers
42 views

Multiplex error

I am trying to do basic multiplexing to see if I can get the basics down. When I apply my pins 7,6,5,4 the LED's go on, but if I remove the pins wires the LED's go off. I make sure to apply no power ...
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2answers
74 views

Need an extra pin to control my driver board

I've been searching for a way to add an extra pin to a driver board. The MCU board that i'm using only has 8 pins on the left side and i'm already using all of them. 2 are for powering the driver and ...
1
vote
3answers
99 views

Dimension RGB LED for peak current

I would like to drive a 3x3 RGB LED matrix multiplexed. This means each RGB LED has 1/9 duty cycle and that means it consumes 1/9 of total current. The RGB LED I am using is designed for max 35 mA ...
1
vote
2answers
74 views

Mulitplexer to read analog values

simulate this circuit – Schematic created using CircuitLab I have a hall sensor that can measure current up to 25 A with analog output 0~5V. I am using Arduino mega board for programming. ...
0
votes
3answers
67 views

Understanding Digital Multiplexing

As I understand it, digital multiplexers contain multiple inputs (2^N), one output, and N selector lines. The selector lines are used to select which input is mapped to the output line. I then ...
0
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2answers
185 views

Multiplexing signals of two wires of a BNC cable and transmitting over a single wire

Background: I have a normal CCTV camera (650 TVL) . It requires a BNC cable in order to feed video signal from camera to DVR. Problem The problem is I have only a single copper wire from CCTV to DVR. ...
0
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1answer
262 views

XY table using motorized potentiometers

I'm trying to implement a XY table using 4 units of these motorized potentiometer, controlled by an Arduino. Since I have other uses in mind, I'd like to use as few pins as possible, wich would imply ...
0
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1answer
170 views

Multiplexing 4 DC motors with arduino

I'm aiming to control 4 motorized faders with an Arduino. However, I'm still trying to figure out how to best multiplex all the inputs/outputs. Each fader has two potentionmeters and one touch ...
0
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3answers
227 views

Can I get away with multiplexing an array mechanical Relays via Mosfets?

I want to use an Ardiuno to drive a Matrix of TO-220 Mosfets triggering mechanical relays instead of LEDS. I am making an array of glow-tubes (read: flickery, purple lightbulbs) as a dramatic screen ...