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Questions tagged [speed]

Speed is a scalar quantity referring to the rate at which an object changes position (but is not position-sensitive).

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Can I calculate how much time it will take for an electrical signal to propagate through a TTL circuit?

Given a particular circuit of TTL, can I calculate how much time it will take for an electrical signal to propagate through some section, or all of, the circuit? If I wanted to know how long it ...
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27 views

DC motor speed calibration

I have seen some treadmills with DC motors that have an option in the console to calibrate the speed sensor by making the motor run from 0 to max speed. Also, some of them have an external ...
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Could we theoretically massively increase number of parallel computations (for some problems) by getting rid of cpu clocking?

CPU clocking involves making sure that each operation or part of an operation takes exactly a certain amount of time (the machine cycle time). One way to increase the efficiency of a cpu is by ...
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How does transistor bandwidth affect stability?

I was watching a video where Dave Jones of EEVBlog interviews Rod Elliot of Elliot Sound Products. Rod was discussing that he tends not to use digital chips in his designs because the chip will become ...
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BLDC motor poles versus Torque and RPM

How to calculate the cost of a BLDC motor? Assume I need 24 stator coils of height 10 mm and width 5 mm. Is there any formula for torque comparison with increasing the number of poles?
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74 views

How does a hall effect wheel speed sensor work?

I have been researching how a wheel or crank speed sensor works in vehicles and am having a hard time finding a hard truth. I think I understand how it works simply. That the sensor detects a change ...
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1answer
34 views

74AS TTL to CMOS pull up resistor and maximum speed (or lowest delay)

Hello I have to pilot a CMOS input 5V chip device with a 7474 flip flop with the lowest possible delay to minimize clock jitter. Signal is about 11.3 Mhz I have two options: 1) 74HC74 (CMOS ...
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2answers
727 views

How is air conditioner room unit fan motor controlled?

I have a custom project where I need to control fan speed with Raspberry Pi according to data it gets from various sensors. At first I need to know what my motor needs. For fans I use old air ...
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71 views

Methods of measuring speed of anemometer

I enjoy DIY, but to keep things simple I purchased an anemometer cupset (3 cups). I feel that a magnetic reed switch would get "bounce" at higher speeds and I was thinking of a disk with a slot, and ...
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74 views

Simple analog circuit to simulate acceleration and braking behaviour in scale models

Background Scale-model road systems such as Faller https://www.faller.de utilise vehicles that follow a ferromagnetic wire embedded in the road surface. The vehicles operate at full speed and continue ...
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1answer
201 views

Measuring speed with Input Capture Mode [STM32 & CubeMx]

I have the L432KC Nucleo. I'm trying to measure low speeds with a 1 PPR (pulse per revolution) sensor. For low PPRs, using the Period Measurement Method is suggested. If I get the period of the signal,...
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59 views

Boosting speed of data on GPIO line between microcontrollers

I made a circuit in which the data bus P0 of an AT89S52 is connected to the P1 of an AT89C4051 and both clocks are each driven by their own 22.1184Mhz crystal. I have used a 10K standard pull-up on ...
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55 views

Sensor range and speed based on resistor

I have 4 of these sensor circuits and can't quite figure out the optimal resistor value to use. Here's what I assume (which somewhere I may be wrong): The datasheet for the IC states leakage current ...
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2answers
62 views

Linearization of motor's thrust

I'm working with a water vehicle that use four motors to move. They are placed at the corner and are fixed. Hence the movements are obtained changing the speed of each one. The vehicle can move along ...
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4answers
570 views

Exotic semiconductors for fast digital ASIC

I am researching exotic semiconductors for a digital ASIC with a few million logic gates which should run as fast as possible within a $30 million budget. (Specifically, I need to do a single fully-...
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165 views

Wheel speed sensor signal amplifier

Need some help with this circuit. A similar question was asked and answered a few years ago here Reading an ABS wheel speed sensor but I need help with clarification. I have an ABS wheel speed sensor ...
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1answer
54 views

how to minimize output resistance

I want to setting up a micro coreless motor (5*20 size) for quadcopter. I use BD139 transistor, PWM from STM32 (31kHz PWM frequency) and 500mA li-polymer battery for this work, but the maximum speed ...
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154 views

Is a 'timeout' of 0.2 ms for UART communication realistic?

In most examples (from Arduino/STM32/whatever) I see timeouts of 10 to 100 ms for different kind of communication. However, I am wondering how much 'overhead' there is. Assuming I want to send 8 ...
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31 views

Speed Controller Terminal/Connector?

I'm kind of confused on what connector (labelled B+, M and B-) this is below: (http://kellycontroller.com/kdz4840024v-48v400aseriespm-p-955.html) This is a 48V speed controller designed for up to ...
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160 views

Induction Motor Torque Slip Characteristics

This question was asked in a interview for Scientist position. For a given T-slip characteristics of an induction motor, I want the same maximum torque but at a lower slip value? Is it even possible?...
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34 views

Stepper calculations and motor speed

I did some basic stepper motor calculations and could anyone please let me know if this is right? For the belt driven systems the max motor speed seems very high (lower bottom corner of the image). ...
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1answer
123 views

stepper motor constant speed under load?

Before posting this question I've been looking up google but can't find an answer to this question other than "speed control and torque control". I've done a lot of research on steppers but still don'...
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1answer
54 views

Speed of a mosfet triggered directly from the logic pin of an Attiny85?

I have a an N-Channel Mosfet soldered to an adapter board and connected to PB4 of an ATtiny85 via a solderless breadboard. The mosfet currently switches the ground leg of some other low power ...
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241 views

Speed calculation using Accelerometer

I am using ST manufacture Accelerometer(LIS2DE12) and i making a small hobbyist project for me. For this I am using ST-Microcontroller and developing the C code i am using KEIL V5 IDE. Configured the ...
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1answer
82 views

efficiency and speed in image processing with FPGA

Hi I have been writing a code in VHDL for some image processing. However, due to some reasons I have not yet determined the sythesis does not stop. I suspect that efficiency of the code is not as much ...
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1answer
58 views

speeding up vivado 2017.2

Hi I am using vivado 2017.2 and it takes infinite amount of time for sythesis and even I suspect that vivado is stuck because I get nowhere. How can I speed the process up? What settings can I change ...
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1answer
74 views

How to get data sent to a LED strip each 400 ns?

I want to send data to a LED strip. This has to be done roughly every 400 (or 800 ns), depending on the data (a 0 or 1 to be sent). unsigned long counter = 0; ...
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1answer
35 views

Mechanisim or Circuit to detect angular position of rotating knob of Motor

I am trying to customize the normal AC motor in such a way that when it will be connected to computer by using some micro controller (e.g Arduino) its rotation will be calculated. i can measure the ...
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57 views

AC voltage through a capacitor

I've built a band pass filter to detect speed using a radar motion detector (IPM-165 http://nic.ath.cx/PDF/sensors/radar/CDM324-doppler/InnoSenT/InnoSenT_application_note_III_11_06.pdf). Using PSpice ...
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2answers
390 views

What is the main reason for using speed feedback in a motor positioning control system?

This question is not to solve a particular problem but rather one of principle to understand the main reason a designer would want to include speed feedback in a motor controlled positioning system. ...
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1answer
536 views

Calculate speed from encoder counts

I'm using the Arduino Encoder library to keep track of my motor's encoder counts. I need to calculate the motor's speed so it can be compared to a target speed and subjected to PID. I've thought of ...
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2answers
69 views

Optimal sensor for measuring object velocity in an open area?

I am trying to measure vertical and horizontal speed of an object attached to a parachute. It will be launched from a low altitude and in an open area, allowing satellite GPS lock. Data treatment ...
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1answer
44 views

Increasing flash rate of xenon flasher

I've come into possession of a bunch of xenon flasher units of the type commonly mounted to burglar alarms and electric gates. I'm aiming to turn them into tiny strobes as part of a project I'm ...
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1answer
772 views

Why does speed of DC motor increase when flux is reduced?

I understand that from KVL e = v -IaRa e=k(flux)speed speed=(constant)*(V-IaRa)/flux But physically what causes the speed to increase? What force causes the rotor to accelerate? In fact, ...
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161 views

Relay Specification regarding switching speed

Newbie here, just wanted to ask some clarification regarding reading datasheet since i don't quite find a standard way to determine switching speed. I already had surf and the closest one was the ...
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1answer
102 views

Convert 0-5 V input signal to 0-100% PWM

I am attempting to speed control two aftermarket DC brushed fuel pumps in an automobile. The OEM pump control works in the following manner: When driving conditions demand a decrease in fuel supply, ...
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Making a ceiling fan speed controller [duplicate]

I was wondering if these can be controlled using a triac, just like light dimmers by chopping the AC wave ?, I read online and some sites say voltage control does not apply to induction motors and ...
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machines 3 phase induction motor

The full load torque of a 3 phase 400 V, 50 Hz,4 pole induction motor is 48 Nm. The motor draws a phase current of 6.61 A. The rotor resistance per phase is referred to stator is 5 ohm. Neglecting ...
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1answer
189 views

DDR3 memory transfer rate

I am trying to understand memory transfer rate while working with DDR3. I am getting different numbers. For example, in Wikipedia https://en.wikipedia.org/wiki/DDR3_SDRAM DRAM has peak transfer rate ...
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2answers
67 views

Detect black/white at 150 mm

I'm facing a weird request. I have to build a sort of "encoder", to detect the direction and the rotation speed of a black/white wheel at 150 mm from my PCB. In the past I did a lot of this things ...
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1answer
89 views

Is this machine code insufficient to chip timing?

I'm having trouble performing basic communication between two IC's. and AT89S52 and an AT89C4051. Both are connected using 6 GPIO pins of which 4 of them on each microcontroller are high nibbles of ...
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178 views

Half-duplex Bit-Banged Port for 8051 microcontrollers too slow?

I was looking at: https://www.maximintegrated.com/en/app-notes/index.mvp/id/3524 and it claims that one can achieve over 2mbps on a 32Mhz clock when bit-banging with an 8051. That means 1mbps on 16Mhz....
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1answer
251 views

3 phase BLDC sinusoidal drive using PWM controller and/or DSP?

My background is mechanical engineering (robotics). I apologize in advance. I have a sensitive torque ripple (Vibrations) application and would like to use sinusoidal drive to run a 3 phase BLDC ...
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1answer
825 views

2 DC motors connected in parallel to H-bridge move with different speed

First of, since I come from web programming world, I'm pretty new into electronics and maybe some of the things I'm doing are wrong or could be done better, so any hint is highly appreciated. I'm ...
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1answer
105 views

How exactly do clock speeds of computers relate to operation speeds?

I was wondering about this the other day when I was explaining binary and hexadecimal to a friend of mine and this came up. The question goes something like this: How exactly do instruction ...
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4answers
1k views

How to reduce the speed of a single-phase induction motor

I have a 1 h.p. single phase induction motor driving a dust extraction blower. The air flow is about 600 cubic feet per minute. The device that the dust collection duct is attached to requires only ...
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1answer
548 views

What is the speed of hard disk actuator arm?

There is a lot of material discussing the rotational speed of the magnetic disk in HDD but not about the rotational speed of actuator arm. What are the typical actuation speeds of the actuator in ...
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93 views

Health index / performance curve of a motor

I am collecting daily data of motors that consists of vibration in three direction x,y,z , RPM, Temperature, kVAh, kWh, kVArh, average voltage (LL), average voltage (LN), average PF, average current ...
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157 views

How to output a voltage proportional to the speed of a DC motor?

Take a DC motor, as the one in the picture below: I need some kind of analogic signal (preferably proportional to the speed of the motor) that can be used in a control loop. What are two simple ways ...
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160 views

using inductor in series with a psc motor

I'm trying to reduce a PSC electro-motor rpm to about 80% to 90% of it's nominal speed. It is attached directly to a centrifugal fan and a mechanical approach is not possible. The ratings are: 450 W, ...