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Questions tagged [tachometer]

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Arduino RPM Calculator Weird behavior

Long time user, first time poster. I've started to fiddle around with Arduinos and electronics and I still have a hard time grasping some of the basic concepts sadly. Here is my issue. I have this ...
sous's user avatar
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0 votes
1 answer
40 views

Connecting a digital tachometer (RPM-meter) to an EC-fan

I have an EC-ventilator with 4 output contacts: +10 V 0-10 V GND TACH (2 pulses per revolution) The first three contacts are for speed control with a 10 kΩ potentiometer. I have succesfully ...
user675169's user avatar
1 vote
1 answer
281 views

Did a PWM fan tach signal fry my ESP8266?

I spliced two PWM fan tach wires and connected them to a single ESP8266 GPIO pin. Since I tried powering this on I couldn't get the ESP8266 back up and running, even after disconnecting the splice ...
Daniel Baulig's user avatar
0 votes
1 answer
64 views

Tachometer for BLDC motors [closed]

Is there any DIY or electronic display kit available that can sense the electrical pulses on the phase wires of a sensorless BLDC motor to calculate the RPM?
Dipendra Gurung's user avatar
0 votes
1 answer
142 views

Electrical tachometer

Could anyone explain to me how electrical tachometers work? I know how mechanical ones do, with cable and drag cup. But i can't find any info or illustration what components drive the electrical ...
wtknow's user avatar
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3 votes
1 answer
246 views

What is the effect of tachometer feedback (derivative feedback) on the time constant of a control system? Does it increase or decrease?

I was going through some practice problems on Control System Modelling and came across this problem. It seems like the answer to this question is that the time constant is "reduced" but the ...
erstan's user avatar
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0 votes
1 answer
564 views

How does my fan have active tacho (RPM) output even though the blades aren't turning?

Whilst working on a project to control and monitor an EC fan from a Raspberry Pi, I have encountered an anomaly that has me completely confused; the fan is still outputting pulses on the tacho line ...
RegEd's user avatar
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0 votes
1 answer
151 views

Current consumption of a tachometer circuit

I am trying to determine how much current this circuit will draw under rest conditions when the Ign- is at roughly 12.5V. Would current run through the blue path? Sourcing from Ign- passing through ...
Feynman137's user avatar
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0 votes
1 answer
764 views

Cleaning up tacho generator signal triggering false interrupts

I'm currently having trouble with detecting the RPM frequency from a tacho generator signal. I have tried everything I know. My tacho generator is attached to a universal washing machine motor, and it ...
nipil's user avatar
  • 35
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0 answers
321 views

Tachometer pulses breaking down at lower speeds

I have a Noctua 4-pin PWM fan (PWM datasheet) from which I'm attempting to calculate RPM using the open collector tachometer output. I'm producing the PWM waveform using a Raspberry Pi Pico. Here's ...
steveh7's user avatar
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1 vote
1 answer
3k views

3-wire fan: Minimum supply voltage for Tach signal?

I want to use a 3-wire fan (e.g. this one), which will be operated closed-loop, powered by a variable DC voltage 0-12 V with tachometer feedback. When requesting a rather low RPM of the fan, the DC ...
tobalt's user avatar
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1 answer
102 views

Tachometer frequency problem

I have an NPN tachometer sensor. I want to measure the rotation speed of a three phase motor, but the output frequency of the tachometer changes. For example, if the actual value of the motor ...
macrobert's user avatar
2 votes
1 answer
211 views

Tacho signal for LED fan monitoring

I am struggling with this problem: I have a fan whose output tacho signal is a square wave when it is running properly. If the fan stops the signal remains at its last value (either high or low). I ...
amsi's user avatar
  • 41
0 votes
1 answer
157 views

Does this motor have a gearbox inside?

I have a DC motor and the sticker says its rated for 24Vdc and 3700rpm. There is an AC tacho inside it which I am using to measure the speed of the motor. So when I run the motor with a 24Vdc supply ...
David777's user avatar
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1 vote
1 answer
286 views

AC Tacho used for speed measurement

I have a task where I want to measure a 24Vdc motor's rotational speed using an AC tacho attached to the same shaft of the motor. When running the motor at full speed, the tacho generates around 9Vac ...
David777's user avatar
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0 votes
2 answers
204 views

Circuit to convert negative voltages to MCU / FPGA

I am trying to connect a tacho that is fitted on a DC motor to an MCU / FPGA. It is being used to provide speed feedback of the DC motor. At full speed the tacho generates around 5.5Vdc which is ...
David777's user avatar
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4 votes
4 answers
2k views

Tachometer IC that does not require zero-crossings?

I recently built the basic tachometer circuit in this LM2917/LM2907 Datasheet shown below using the 8-Pin version of the device. I realize this circuit requires a VR pickup sensor, and so the LM2907/...
user avatar
2 votes
4 answers
196 views

How to distinguish a DC generator from an AC generator

I have an electrical generator (a tachometer really) and I want to know how can one detect if it is AC or DC? (what if it is dead and can not be tested for its output?) I add the image if some of you ...
kavehmb2000's user avatar
2 votes
0 answers
124 views

Puzzle: diode polarity in a vintage tachometer circuit

Once again, I'm trying to reverse engineer an old tachometer circuit--1970s vintage this time. There are three diodes on the circuit board, and two have absolutely no markings whatsoever. Can anyone ...
Bill Catlin's user avatar
1 vote
2 answers
86 views

ID a green ceramic component from a tachometer?

This component is from a 1960-70 vintage boat tachometer. It's about 1.25" long. It generates not a single reading on my 11-function multimeter (including capacitance). I may have fried it ...
Bill Catlin's user avatar
3 votes
1 answer
604 views

Old tachometer rectifier(?) components

I'm trying to reverse engineer the intermediate circuitry of a 1960s vintage marine tachometer made by a now defunct firm called Airguide. Airguide referred to the black box as a "transmitter.&...
Bill Catlin's user avatar
0 votes
1 answer
102 views

Voltage Regulation for a high frequency signal - Arduino Input

I'm trying to build a digital tachometer for my motorcycle using an Arduino nano. I have researched a lot on how to reduce the 12 volts from tach signal to 5 volts to be read by the arduino. One post ...
HaiderZia's user avatar
0 votes
1 answer
2k views

3 wire PWM fan tach signal [duplicate]

I am using the 3 wire PWM fan. By measuring the signal on the 3rd wire (yellow color) on the oscilloscope, the signal is square wave output. Can anyone tell me how this tach signal indicate the speed ...
Dush's user avatar
  • 21
1 vote
2 answers
421 views

Automotive tachometer signal interpretation

I'm trying to build a custom dashboard for a car (Daewoo Lanos 1998 with Delco ECU). Tachometer signal, that comes to dashboard with a separate wire looks a bit strange to me. It seems that the signal ...
Ruslan's user avatar
  • 21
1 vote
2 answers
769 views

Op-amp (LM358N) half-wave rectifier and 3.3V clamp

I was wondering if I could have some feedback on this circuit. The goal is to: Input up to 18VAC sine waves (possibly noisy) up to 20khz. Output 3.3V digital pulses. Minimize discrete part count. I ...
hype's user avatar
  • 41
1 vote
2 answers
556 views

Converting DC motor's tachometer output to DC using bridge rectifier

I have a DC motor, its specification states: "Electric DC motor manufactured by Buehler. Sinusoidal Encoder Output: 11.5 VAC - 870 Hz @ 12 VDC input. No load speed: 6800 RPM. Runs in either ...
Steve Chung's user avatar
0 votes
2 answers
2k views

Tachometer Signal Voltage Reduction

I am working on a formula style car and creating a digital dash based on an Arduino. I currently have a signal from the ECU running at 12v DC and a varied frequency depending on the RPM of the engine. ...
Connor Davey's user avatar
0 votes
1 answer
40 views

How to get the forward voltage of a tachometer?

I am currently in the process of building a circuit board for components that I am going to use on a lathe. I want to use this tachometer. I have checked out the manufacturer website but it’s not in ...
David Allen Hagins's user avatar
1 vote
3 answers
794 views

Dimming LED based on 12 V signal

I've got an LM358 comparator turning on an LED. What I'd like to add is a way to dim the LED by a fixed amound when a 12 V signal is sensed. It's in a tach circuit in a car, and when the headlights ...
mojozoom's user avatar
3 votes
1 answer
828 views

Spark plug pick up

This is a reformulated question to make it shorter. I would like to build a tachometer for an old moped. Since my moped has a magneto and points for ignition I must obtain the signal directly from ...
Blaž Umek's user avatar
1 vote
0 answers
1k views

Component identification from vintage tachometer

For the purpose of understanding how it works, I'm attempting to reverse-engineer the schematic of an analog gauge. For some context, it's an analog tachometer from the 70s, with a scale from 400 to ...
John M's user avatar
  • 329
0 votes
2 answers
5k views

Tachometer vs. Tachogenerator

Could you explain to me the differences between a tachometer and a tachogenerator? For example, is a tachometer just a tachogenerator attached to a dial to display RPM rather than voltage or are they ...
Steven's user avatar
  • 189
2 votes
1 answer
3k views

12v PWM Fan Seems to Be Running Inversely of What It Should Be

I have a 120mm 12v Fan that is used on an Antminer S7. There are two fans on the antminer, and they both are controlled by the software built in. I had one fan break, so I replaced the fan with a ...
B-Dawg's user avatar
  • 191
-1 votes
2 answers
814 views

Understanding an Ignition Circuit

I found the below schematic here to while trying to build a tachometer for my motorcycle. What does the circuit element labeled "BOARD" mean (directly left of the 22pF capacitor) - is it just a wire ...
Andrei Grigore's user avatar
0 votes
1 answer
244 views

Electronic tachometer over reads

The electronic analog tachometer on my small boat diesel has recently started to overread on startup of the engine (e.g. it reads 2000 rpm on idle). After about 5 - 10 minutes it drops back quite ...
Andrew's user avatar
  • 1
1 vote
1 answer
2k views

How to read signal from Crankshaft Postition Sensor in motorcycle

I am trying to build digital tachometer for my motorcycle Yamaha FZS600 Fazer 2002. I have a problem with reading signal from CPS sensor. It is hall effect sensor, I suppose. I found the plug of it. ...
BartholomeusR's user avatar
2 votes
2 answers
780 views

12 Vdc Intel fan tachometer output to 24 Vdc PLC input

I'm working on a cooling fan rotation supervision system, and I'm planning to use my old 4-wire Intel E18764 12 Vdc cooling fan to test it (as I don't have access to the 24 Vdc actual fan I'm going to ...
stmas's user avatar
  • 21
1 vote
2 answers
4k views

Motorcycle RPM counter

My plan is to make RPM counter to my motorcycle. I'm planing to read ignition box signal with arduino. I think that ignition box gives 0-12V (or 14.5V max) square wave signal to coil. I was wondering ...
kah's user avatar
  • 13
1 vote
4 answers
7k views

Finding RPM of DC motor

How can we find the RPM of DC motor using the given voltage?. To be clear, I need to find out rpm of a motor using the pwm signal sent from Arduino Uno. In my case i'm using a BO motor, the link is ...
Assazzin's user avatar
0 votes
1 answer
950 views

Reading ECU tacho signal with PIC MCU - noise issues

Am trying to read the frequency of a 0-12V square signal generated by a motorbike ECU with a PIC. Range 20Hz-300Hz I'm getting strange intermittent noise on the output of my optoisolator, and wondered ...
J Warner's user avatar
0 votes
3 answers
1k views

How do I convert voltage square wave signal to 4-20mA signal

At school we are looking for a sensor that is able to count/sense the rpm that the shaft is turning at. I have found a sensor which does this but it sends out a voltage square wave: Datasheet I need ...
Arjo's user avatar
  • 3
1 vote
1 answer
1k views

Photodiode -- photoconductive (reverse bias) vs photovoltaic (zero-bias) for tachometer

I'm building a tachometer for speeds 0 to 3600 rpm (various speed motors turning things down to whirligigs blown by the kids.). I've got a photo diode running in photovoltaic mode generating about 50 ...
HiTechHiTouch's user avatar
-5 votes
3 answers
3k views

How do contact type tachometers work? [closed]

In case of contact type tachometers we put the tip into a small hole in the rotating body. Sometimes there is a disc in the tachometer shaft that we touch with the surface of the rotating body. What ...
Dwiparna Datta's user avatar
1 vote
2 answers
1k views

Diodes in Tachometer Circuit

How are the diodes helping in the attached ckt :-
Oshi's user avatar
  • 591
5 votes
1 answer
2k views

Converting a tachometer signal into something a microprocessor can understand

I am attempting to build a digital dashboard for my car (a 1998 honda civic), I have run into a bit of trouble, wherein the tachometer signal is quite hairy. I was wondering if someone would lend me a ...
Patrick's user avatar
  • 206
3 votes
1 answer
3k views

Read out tachometer from PC fan when manually turning the blades ( driven shaft )

I have a problem. I can read out the tachometer of a PC fan and convert it to frequency with just using a simple microcontroller and labview. Does anybody here have an idea how to read out the ...
jemas's user avatar
  • 31
2 votes
2 answers
884 views

LED tachometer with PIC MCU (requires more current)

I've been working on an LED tachometer that will be installed on an open wheel race car. After putting the order through for the PCB I re-calculated the current draw and turns out the PIC's (16F877A) ...
user18987's user avatar
2 votes
2 answers
2k views

Inductor ground, where to put it

So I'm building a tachometer for my car. It's pretty simple, basically I have a wire wrapped around the spark plug wire about 10 times, and the 30-50k volts travelling through the spark plug wire ...
rozap's user avatar
  • 131
1 vote
1 answer
745 views

How do i build a laser based tachometer?

I want to build a tachometer that has to be somewhere around 1 meter from the rotating shaft. I'm still to build a prototybe based on IR diode and phototransistor, but I'm afraid, I would get too ...
miceuz's user avatar
  • 5,571