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21 votes

Calculating pitch, yaw, and roll from mag, acc, and gyro data

Pitch, roll and yaw are defined as the rotation around X, Y and Z axis. Below as a picture to illustrate the definition. In a previous project I used a ADXL345 Accelerometer from Analog Devices to ...
14 votes

How to quantify martial arts strikes?

You could just hit a pendulum and measure the angle to which it swings. I have found that three liter soda bottles filled with water and hanging from a rope are good for hitting. Knowing the weight of ...
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13 votes
Accepted

Can I use a ultrasound sensor to measure water level?

Technology used in depth finder, in marine application is mostly like is the best to measure the water from the top. To measure water level from the bottom of tank one could use a piezo electric ...
12 votes

Calculating pitch, yaw, and roll from mag, acc, and gyro data

So my longer answer below assumes that the board will undergo acceleration and during this time you still need to be able to measure your pitch, roll and yaw within a short amount of time. If the ...
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10 votes

How to quantify martial arts strikes?

I think that an impact force sensor is what you're looking for. I'm not sure how expensive the linked sensors are so you could also use an acceleration sensor and do a little math. The second option ...
10 votes

How to quantify martial arts strikes?

I think what you want is a piezoelectric pressure sensor. You might be able to steal one from an old bathroom scale, but the sensors in a scale may only be good up to ~100 lbs of force. These ...
7 votes
Accepted

Can the structural integrity of bridges be measured in real-time for safety?

There are many different sensors that can be placed on a bridge to help monitor its condition. After the I-35 bridge collapse, this area has seen a lot of publicity. Most of these sensors were ...
  • 10.7k
7 votes
Accepted

What kind of motion information can be extracted from 3-axis accelerometer and 3-axis gyroscope sensor data

This information you have, in theory, allows complete reconstruction of location and orientation of the bike along the entire path. This is basically what is referred to as inertial navigation. ...
  • 11.3k
7 votes

Seeing through walls and noninvasive structural integrity metrics

Depending on the region and structure of building the techniques might vary. Below are few suggestions Termite inspection is another popular method to determine the structure integrity of building. ...
7 votes
Accepted

Alternatives to laser line?

A few points that don't fit into a comment but could help you: Get a better laser source than a 4 \$ laser diode. "Better" means a laser with higher beam quality. When you look at a laser's ...
6 votes

How can I measure the thickness of a sedimentation layer in a closed tank?

Buy a depth finder! As @SF pointed out, you can use an ultrasonic device to measure the depth of the water. These devices work by sending out an acoustic impulse and recording the return signals. ...
6 votes

How to quantify martial arts strikes?

Conductive foam will change it resistance when compressed, so it makes a good, cheap force sensor, as long as you have a system to make many measurements in quick succession and remember the one with ...
6 votes

Can the structural integrity of bridges be measured in real-time for safety?

Real-time monitoring can be done and has already been done. The technology is there and as pointed out by hazzey, is a matter of cost versus the risk involved. As a practising Engineer, I am/was ...
6 votes
Accepted

Distance sensors with accuracy of 1 mm?

Answering the question: What are possible types of low cost sensors I can use? There are several types of sensors that can provide millimeter level accuracy. "Low cost" is a very relative term, ...
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6 votes

Can I use a ultrasound sensor to measure water level?

Yes To answer your specific question, yes, you can use an ultrasonic sensor to measure fluid level. Mahendra's answer describes that. You mentioned that you feel that an ultrasonic sensor is the best ...
  • 10.7k
6 votes

Help with closed loop heat controller (for a non engineer)

Since you seem to not be too familiar with control systems, electronics, and wiring things, I recommend a simple threshold detector that controls a relay. The relay then switches the heating element ...
  • 11.3k
6 votes

Would it be hard to create a camera that could see the whole electro-magnetic spectrum?

Look at it this way: A simple compass will detect from zero to about 0.1 Hz your AM radio detects around a MHz your cellphone around a few GHz or so Radar systems anywhere from 100kHz to 1 THz ...
5 votes

How to quantify martial arts strikes?

I agree 100% with Jeff, the advantage of this is that you could build it for cheap, very, very solid. The height it swings to will give you the energy with the formula $E=mgh$ where E=energy in ...
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5 votes
Accepted

What is Radial and Thickness Mode Vibration in a Piezo Electric Ceramic Disc Transducer?

There is an excellent white paper from piezotechnologies.com which is probably worth a read if you are new to working with piezoelectric devices. Quoting from the section on resonance frequencies: ...
5 votes
Accepted

What is meant by the terms "low pass sensor" and "band pass sensor" in a course syllabus?

You are combining two concepts. A sensor is any device that responds to a desired signal in some manner to produce an output that is used to detect the presence of the desired signal or to allow ...
4 votes

What is Radial and Thickness Mode Vibration in a Piezo Electric Ceramic Disc Transducer?

Radial: Oscillatory waveform is between edge and centre. Thickness: Oscillation is across disc faces so will be higher frequency all else being equal. Axial and thickness are probably equivalent ...
4 votes

How to quantify martial arts strikes?

The problem with quantifying impact force is the short duration of what is usually a 'peaky' pulse. Bathroom scales are usually damped to give a steady reading of a static force and won't capture ...
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4 votes

How to quantify martial arts strikes?

Here is a really cheap and cheerful way of showing the size of an impact. Take 2 boards of plywood, put a large compression spring between one and the other board so the spring is sandwiched but ...
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4 votes

How to quantify martial arts strikes?

A strain guage attached to a target would be helpful. Unlike piezzo, they are very durable against impact type force (piezzo crystals tend to shatter when the pressure is applied rapidly). They can ...
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4 votes

How to quantify martial arts strikes?

These are few suggestions to develop the system I suggest using a polymeric bladder type approach used in Passage Occupancy Detection Systems in automotive industry. This patent describes the ...
4 votes

How to sense displacement without using any camera?

I can say using accelerometers to detect displacement won't work. These devices have so much of inherent noise that discerning very slow acceleration from remaining immobile is about impossible. You ...
  • 6,133
4 votes

What type of sensing element is used in Water Quality Monitoring Meters?

Hand-held sensors measuring multiple properties may require more than one type of sensor element; it's important to know what exactly you need to measure. There is no one property (or fixed set of ...
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4 votes
Accepted

How do ultrasonic proximity sensors detect motorcycles differently from cars and trucks?

It is likely that the noise of the motorcycle is causing the sensor to activate. This listing of the advantages and disadvantages of ultrasonic sensors lists one of the disadvantages as: While ...
  • 10.7k
4 votes

How can I measure the thickness of a sedimentation layer in a closed tank?

If you want this automated, probably Rachet's solution is better; for a more low-tech approach for periodic manual testing, a wide, flat weight on a rope will work; lower it below water surface, let ...
  • 6,133

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