6 votes
Accepted

Measuring a pattern size on a flat surface

I had a plastic ruler at one time in my life and it looked something like Figure 1. Figure 1. Overview. Figure 2. Close up of precision grid. Figure 3. In-use. How to use: Align the right edge to ...
  • 8,824
4 votes

M# Screw mm per turn?

Metric bolts use thread pitch in millimeters. Your M3 screw likely uses the standard pitch of 0.5 millimeters. One complete rotation of the screw will advance the screw into the work piece by that ...
  • 6,427
3 votes

Can two microphones placed within centimeter distance together measure a distance of the sound source?

A sound source and listening device can only provide direction. Multiple microphones is how passive submarine sonar works. This will give direction only. Note that microphones in a line can only ...
  • 4,953
3 votes

How to take dimensions of an underground tank

Depth can be measured by dipstick whether partially full or not. A range of ultrasonic "tape measures" in a Google image search. Distance from the manhole to the walls should be measurable ...
  • 8,824
3 votes

M# Screw mm per turn?

A metric thread table is what you want. Table 1. Source: Anzor. So is there a standard rule of thumb, or equation about the distance the end of a screw will travel per rotation? It's not a rule ...
  • 8,824
3 votes

What is best sensor & method to measure human height?

Hair is mostly transparent to ultrasonic, so this is still the reliable&convenient approach - any EM spectrum readouts (3D, video, laser) will be completely falsified by hair. You just need a ...
  • 6,133
2 votes
Accepted

Measuring the distance to an object with RF resonance

I do not believe this will be an effective scheme. The $Q$ of a resonator, a number which describes the strength of the resonant peak, is given by $$ Q=\frac{f_0}{\delta f}\approx f_0\frac{2\pi\ t_{...
2 votes

Measuring the distance to an object with RF resonance

I'd put this in the not possible/very difficult category. Simply because if you are dealing with RF your wavelength is going to be on the order of 10cm - 1m+ which is going to place a limit on the ...
  • 1,025
2 votes

How to measure height of water

How about using a Capacitive Fluid Level Sensor from Molex. The sensing element can be affixed outside of the tank. Here is an image of the sensing element affixed outside of the a container. . ...
2 votes

Measuring a pattern size on a flat surface

I would give a shot at image processing, if there is a good contrast between the surface you want to measure and the background. To do so you need to take a picture of the surface that includes an ...
  • 174
2 votes
Accepted

US customary units below 1 mil/thou?

50μm → 0.002" or 2 thou or 2 mils? I've seen both 0.002" and 2 mils. On a drawing it would always be 0.002". In a specification document it could be either. I've never seen 2 thou written in a ...
  • 2,526
2 votes

Could a medical ultrasound device be used for recording the topography of a small river?

I've had the possibility to test several different diagnostic ultrasound devices in a big bucket of water with gravel at the bottom! The result is interesting: At first, for all devices you have to ...
  • 51
2 votes

Is it possible to estimate location of a source of light using single camera?

Yes, as discussed on SO – Is it possible to measure distance to object with camera?, Finding distance to an LED SE Physics – How the calculate distance of light source it is indeed possible. However,...
  • 334
1 vote

Can two microphones placed within centimeter distance together measure a distance of the sound source?

If the distance you want to measure is small than maybe you can use one of the microphone as a sound source. But using a active sound emitter would be a better option.
1 vote

How do Time of Flight (ToF) cameras work

The short answer is that the receiver (camera) can only determine the signal's source to the limit of the field of view (FOV) of the lens + pixel system. That is, the lens produces an image on the ...
1 vote
Accepted

object following using pid

Forget PID at first. If we assume PID, we're skipping steps. Write down what we know. From your description: process variable : position input : (other robot's position - following distance) loop ...
  • 1,367
1 vote

How to measure height of water

I do work for a company that makes sensors that might be applicable. These sensors are used, among other places, to measure levels in ballast tanks of ocean-going ships. The possible gotcha for your ...
  • 11.3k
1 vote

Measuring intensity of a radio wave reflected from a metal plate

Typical distance sensors depend on time-of-flight. If you're trying to hack the distance from return power level, you will not be happy (to put it mildly). It's next to impossible to calibrate any ...
1 vote
Accepted

Stretching material accurately with a machine

Yup, You could use something as simple as a bar clamp. Most hardware stores will carry some version. The type you'd need is the type that can be reversed to a spreader (95% of them can do this just ...
  • 632
1 vote

Stretching material accurately with a machine

If you are at a university, you can consider using a universal tensile testing machine to stretch the rubber cord at specific stretch rates. Otherwise, you may develop a simple setup using stepper ...
  • 29
1 vote

Precision measurement of liquid level in a tank which is continuously opened and closed

Maybe you could use one of the following: level glass allows you to read the height of the liquid outside the tank. The width of the tube would have to be large enough for capillary action to ...
  • 1,186
1 vote
Accepted

Short range distance estimation systems

I think you have approached your problem from the wrong direction. There are currently no sensors that measure distance between each other regardless of material in the path. It would be possible to ...
  • 7,499

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