# Questions tagged [measurements]

Measurements, instrumentation, calibration and metrology.

48 questions with no upvoted or accepted answers
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165 views

### In what cases are the roughness values Rt and Ra used?

Roughness measurement instruments output those two values, where Rt is the distance between the top of the highest peak and the bottom of the lowest valley, and Ra is the average distance of every ...
49 views

### Is sensor measurement uncertainty the same with its calibrator?

I'm trying to calibrate a proximity sensor A with another proximity sensor B. Say sensor B uncertainty is already known from the data sheet. However, for sensor A the uncertainty is nowhere to be ...
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### Measuring an irregular cavity

A friend has a compartment in the center console of his car, he has asked me to help resize, reorder and add padding to the compartment. Basically the kind of things I'd need to know are the ...
135 views

### In Solidworks Hole Toolbox, what is Thread Minor Diameter according to DIN 13-1

Dear StackExchange Community, I recently discovered how to use the Toolbox customization to specify new threads in Solidworks 2021 SP2.0, such as ISO fine metric threads (DIN 13-3- ... -9). However, ...
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### How can I calculate the smallest voltage a given adc can read?

I have a project where I'd need to measure small voltage (0.05 mV) output of a wheatstone bridge with an arduino mini pro. Based on my previous question most probably it can't be done with its ...
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### How to measure the inertia of an object using a motor

first time on this board even if I've been lurking for a while. I'm a tennis racquet technician and, for the sake of saving some money and just for the fun of it, I'm trying to build a machine that ...
66 views

### Maintaining constant speed of a CVT engine during a slope

I am not sure if this question is related to this community. But nevertheless. I work on CVT engines, I had a new idea of modifying my controller during a slope or a gradient on the road so that the ...
40 views

### Finding liquid viscosity

I'd like to calculate the viscosity of a liquid in a container systematically (and feed the results back to a computer). I only have basic knowledge of physics and mechanics. I think that a motor ...
68 views

### Measuring Helix Angle

What is the best way to measure the helix angle of a helical cut gear? I have a sun gear from a planetary set that I would like to have custom made but I'm not sure the best way to get the helix angle,...
32 views

### Measuring moisture in walls remotely

There exist devices (e.g. Bosch PTD 1) which measure the temperature and humidity/moisture of the room and remotely (without contact) of a wall they are pointed at. I understand that you can measure ...
52 views

### Ambient helium level monitoring

I am looking for a solution to monitor and log ambient He levels down to 50-100ppm. The detector is meant to be installed in an experimental hall where a large number of Photo Multiplier Tubes are ...
886 views

### Hydrogen in submarines: "keep below 8%" rule of thumb?

In the book "Against the Tide: Rickover's Leadership Principles and the Rise of the Nuclear Navy", Rear Admiral Dave Oliver (Ret.) narrates some of his experiences in the USS George Washington Carver, ...
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### Decission between several position switches and one continuos position signal for controling rotating conveyor

We plan a conveyor that will dump something into containers. A level gauge on the tip of the container will measure the heap below. The conveyor is placed on a turntable and will e rotated ...
35 views

### Looking for a loadcell in the shape of a truss rod

Today I found myself looking for force measurement device (load cell) that can be easily attached to a educational truss structure (i.e. replace a rod in a truss). I'm sure that there are bound to be ...
37 views

### Help on IR Proximity Sensor Inaccuracy

I want to measure the depth of a burning soil using IR proximity sensor. The sensor will be placed 20cm above the surface of the soil and measures it perpendicularly. Problem #1: I'm quite concerned ...
215 views

### Tolerances in a pin-hole assembly

Hi guys, can someone explain how to do this question? This question is under Geometric Dimensioning and Tolerances and I am clueless on how to tackle problem like this. EDIT This is the explanation ...
26 views

### Finding force distribution using accelerometer data

The team I'm currently working for is trying to compare bushings with different durometer ratings in the front suspension using single axis(z) accelerometer data during curb impacts. The current ...
25 views

### Is there an instrument that can measure thickness of an object through strain?

So basically, I am doing a project to design a measurement tool for measuring the different layers of the quartz crucible used in the semiconductor industry. Since the crucibles undergo some ...
96 views

### BJT Output Characteristics Question

Ok, so I am pretty confused at the moment with a question that I have been given to work out by my lecturer and was wondering if I could get some guidance with it. I will attach images of the question ...
17 views

### how do you calculate viscocity from torque arm load cell measurements?

I have a piece of company developed equipment that uses a pot mounted on a rotating base plate with a 0.15m torque arm and load cell, a mixing paddle is used to stir the mixture while the controller ...
93 views

### off-scale torque measured - what is my torque arm?

I have assembled a benchtop torque measurement stand for evaluating electric motor and controller efficiency. The motor is 49kV , 5kW brushless outrunner. Input power reading is taken from motor ...
161 views

### Which imperial units of measurement use vulgar (simple) fraction numbers?

All values of metric units are expressed in decimal or scientific notation. Some imperial units, use fraction numbers as primary notation (3/4" for 0.75 inch). As far as i know, only inch and foot ...
56 views

I am looking into using this TAL230B miniature type load cell to measure forces in x and y direction. The normal sensor loading is displayed in image 1. What is the effect of loading them as in image ...
47 views

### Strange offset on oscilloscope channel

I've a Rigol DS2072A. It works great except for an offset problem that I noticed the past few days. Channel 2 always shows a DC offset. This is independent of any settings such as channel coupling, ...
432 views

### Detergency and dispersancy

Abstract:The detergency property in oil comes from a chemical additive called detergent which has a property of preventing the deposition of carbon deposits and wash it away. There is also this ...
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### What conditions to properly measure surface resistivity using surface resistance meter?

I have some JEDEC trays that I need to measure it's surface resistivity. I have a surface resistivity meter to measure it, but I do not know what environmental conditions it is supposed to be measured ...
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### Doubt related to venturimeter and manometric fluid

I am unable to understand why the manometric fluid do not flush off due to high pressure fluid flowing through pipe? Because as discharge increases pressure drop will increase so manometer should show ...
42 views

### Direct way to measure perpendicular movement?

I'm planning a CNC machine build which will use many linear slides with bearing blocks moving on them. Some of these need to be in parallel with each other and others perpendicular to each other. It ...
38 views

### How do you calibrate an inverted U-tube?

Say you make a U-shaped glass tube. If you fill it with water you are able to measure gas pressure by looking at the height difference of the meniscuses. In an inverted one, by turning it upside down ...
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### Why would a magnetic sight glass indicate a wrong water level in a surge tank?

In a pumping station that i work, there is a magnetic sight glass attached to a surge tank which I guess there is something wrong about it because when I isolate the tube, drain it and reopen the air ...
520 views

### How to use Spectroid app to measure low frequency vibrations?

I need to measure how low frequency (vibration) changes when going through different materials. The only possible way I found is by using Spectroid app. However, I have no idea of what settings to set ...
29 views

### Vibration measurement of rotating blade

In a vibration measurement of a rotating blade, I have the following information. The vibration signal is measured using an ICP accelerometer which has the following specification Measurement range: ...
29 views

### How does the number of cycles for averaging in a lock-in amplifier relate to low-pass filtering and where do I set it?

Please forgive me if I ask too many questions at once or I am too much of a rookie. I want to understand the working-principle of lock-in amplifiers (LIAs). I understood the calculation that yields ...
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### Estimating trunk rotation using frontal and sagittal views

I am doing an experiment regarding elbow flexion's effect on peak sprinting velocity and we want to measure trunk rotation and shoulder rotation during our trials. We don't have an overhead camera so ...
32 views

### How to measure and create PVT diagram

We have all seen PVT diagrams. From my understanding one should measure pressure, volume and temperature on or near the outside of the system. Volume: maybe by displacing water initially and then ...
30 views

### How to design a method to estimate vx=speed in direction of swimming

We have a body that goes underwater (let's say a whale) with magnetometer and accelerometer data. I also have GPS, date, depth, pressure and temperature data. I want to know if there is any simple way ...
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I was reading about characteristic of a comparator. It states Comparator indicator device should be such that the readings are obtained in least possible time and for this magnification system should ...
31 views

### Why is there no widely-used standardized unit for indentation hardness?

The last hundred years have seen a great degree of standardization of units, and the expression of units of measurement in standardized, instrument-agnostic, objective terms, often in the SI units. ...
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### Typical range of a small hole gauge.

I want to get this out there. What is a typical and common range of a small hole gauge?
61 views

### Can foil strain gauges measure strain normal to the plane of the sensor?

I'm wondering if anyone in the community has experience with foil strain gauges used to measure strain components that are normal to the plane of the sensor? If the strain gauge were pressed between ...
105 views

### Automated valve for testing module

I work frequently with materials sensitive to oxygen and moisture, within a glove box. However, there are frequently times I want to move these samples from the glove box to a scanning electron ...
71 views

### Safety factor for pressurized container at 10 ATM

There is no secondary containment to hold any potential shrapnel. How would this change the safety factor that is standard at 2.5? The consequences of this container exploding would be quite extreme ...
46 views

### What type of acturator with motor to choice for measurement with step = 0,25 μm?

I need to select some linear acturator or build it. I see it as: On green platform there is pink device. This device must be measured. For this purpose we need to choose linear acturator with ...
375 views

### How can I measure the coefficients of friction of pulleys?

I have to study several industrial pulleys made for lifting heavy weights. It is important to select one which has a low coefficient of friction because the system is based in a hoist and several ...