What would be the cost/difficulty of setting up an accelerometer into a target

[Dirty Dog]

Racers have been using smart phones to measure reaction time, acceleration, wheel horsepower, ET, trap speed, braking performance, and corning ability for years. I've used them myself, and the numbers match up very well to the numbers I get at the track. All done via an app and the onboad accelerometers.
So why wouldn't they work perfectly well for this as well?

 

[pdg]

Racers have been using smart phones to measure reaction time, acceleration, wheel horsepower, ET, trap speed, braking performance, and corning ability for years. I've used them myself, and the numbers match up very well to the numbers I get at the track. All done via an app and the onboad accelerometers.
So why wouldn't they work perfectly well for this as well?

Range of response maybe...

If I stick my phone to my dashboard it'll easily measure stuff like 0-60-0, or cornering forces. I can even use an interface plug to connect to the OBD port, and use the camera and mapping software to record all the forces and overlay that data on a map of the course.

If I kick my phone it'll likely be outside the range of what the sensors are capable of reading.

And it'll probably break.

If I pad it, then I have to somehow account for the discrepancy in reading caused by the absorption of the padding material - which is something that's easy enough to calculate, but is it something I can tell the phone to account for (without developing my own app)?

 

[Dirty Dog]

Range of response maybe...

If I stick my phone to my dashboard it'll easily measure stuff like 0-60-0, or cornering forces. I can even use an interface plug to connect to the OBD port, and use the camera and mapping software to record all the forces and overlay that data on a map of the course.

If I kick my phone it'll likely be outside the range of what the sensors are capable of reading.

And it'll probably break.

If I pad it, then I have to somehow account for the discrepancy in reading caused by the absorption of the padding material - which is something that's easy enough to calculate, but is it something I can tell the phone to account for (without developing my own app)?

On what info are you basing your opinion of what range the sensors are capable of handling? Frankly, if you think your kicks move things more abruptly than a hard launch at the drag strip, you've just never been in a car that launches hard.
As for calculating, that IS what the app is for. Calculating stuff.
In any case, all you really need for this to be useful is numbers. Get some. Train. Did your numbers improve? Then it worked.

 

[pdg]

On what info are you basing your opinion of what range the sensors are capable of handling? Frankly, if you think your kicks move things more abruptly than a hard launch at the drag strip, you've just never been in a car that launches hard.

Yeah, I was expecting that...

It's a different type of force in a different concentration that requires a different system of measurement.

In any case, all you really need for this to be useful is numbers. Get some. Train. Did your numbers improve? Then it worked

That much I completely agree with.

Kick a ball - how far did it go? Train, kick it again - did it go further?

 

[Dirty Dog]

Yeah, I was expecting that...

It's a different type of force in a different concentration that requires a different system of measurement.

How is it different? Acceleration is acceleration. I don't see that it really makes any difference if the acceleration is from a rocket, a car engine, or a kick.

 

[pdg]

How is it different? Acceleration is acceleration. I don't see that it really makes any difference if the acceleration is from a rocket, a car engine, or a kick.

If the rate of acceleration or deceleration is beyond what the sensor is capable of handling, then it won't work.

To go back to the car vs. kick, in the video the people had the sensor strapped to their foot - so, for direct comparison that's like recording the force from driving said car into a wall.

 

[pdg]

So, a phone accelerometer.

Is it useful?

I got an accelerometer app, switched it on, tucked my phone in my sock (like on the kick comparison video, kinda) and kicked a wall with nowhere near my full capacity.

I exceeded the range of the sensors.

In other words, off the fricken scale.

In other other words, my kick is more powerful than a drag car without me even putting any serious effort in



Edit: the figures at the top are live, that's how much movement was occurring to take the screenshot.

 

[pdg]

Actually, let's look at that picture a bit more.

There are positive and negative values shown.

One will be the acceleration of my foot from chamber to impact, the other will be the deceleration of my foot when it hit the wall.

Both figures are off the scale.

With not much effort at all, I exceeded the range of the sensors to measure both acceleration and deceleration.

I am a kicking god!!!!

Alternatively, a phone just isn't made to record impact forces...

(I choose the former option)

 

[jobo]

I am build a BOM for a project and was looking up sensors. I found an accelerometer that measures 7Mv/g to 11Mv/g. A pretty small range to scale and interpret. Knowing 1 Mv would mean one G of force is easy enough but that is very raw and only give you a 5 point range. Sure you can set down and create a worksheet to plot the points in between but trying to make these very small measurements with a handheld unit is tough and not very reliable. Just the sensor is about $50 bucks and it looks robust enough to attach to an end effector (pad, board, etc...). I can understand the prices of the commercially available accelerometers. The use the frequency of vibration so you can also look up vibration sensors and do the same thing.

I can see why that might cause you problems, force is measured in Newtons not " g", g is mea unless unless you know the weight of what ever object it's attached to, if were you, I would take that back to Tandy

 

[jobo]

So, a phone accelerometer.

Is it useful?

I got an accelerometer app, switched it on, tucked my phone in my sock (like on the kick comparison video, kinda) and kicked a wall with nowhere near my full capacity.

View attachment 21658

I exceeded the range of the sensors.

In other words, off the fricken scale.

In other other words, my kick is more powerful than a drag car without me even putting any serious effort in



Edit: the figures at the top are live, that's how much movement was occurring to take the screenshot.

Hang on that measure acceleration if your foot not energy, and not force,,, to make a useful measure you would need to fix it to the wall and we how fast the wall accelerated after you kicked it then times that by the weight of the wall,, Or stick on the back of a heavy bag,,,I'm quite sure most people can accelerate their foot faster than a drag car, T least for the first meter

 

[pdg]

Hang on that measure acceleration if your foot not energy, and not force,,, to make a useful measure you would need to fix it to the wall and we how fast the wall accelerated after you kicked it then times that by the weight of the wall,, I'm quite sure most people can accelerate their foot faster than a drag car

So wait, are you saying that what we'd actually get anything meaningful from measuring is a different type of force that requires a different system of measurement?

Yeah, I was expecting that...

It's a different type of force in a different concentration that requires a different system of measurement.

 

[jobo]

So wait, are you saying that what we'd actually get anything meaningful from measuring is a different type of force that requires a different system of measurement?

No not a different type of force, just force which is based the acceleration of the target after contact, not the acceleration of your foot which would be energy measure in kj not force measured in Newtons

 

[pdg]

No not a different type of force, just force which is based the acceleration of the target after contact, not the acceleration of your foot which would be energy measure in kj not force measured in Newtons

Joules and Newtons are measurements of different types of 'force'. One can be extrapolated from the other (if certain other variables are known), but they are not comparable.

Let's see your effort then?

 

[jobo]

Joules and Newtons are measurements of different types of 'force'. One can be extrapolated from the other (if certain other variables are known), but they are not comparable.

Let's see your effort then?

there is ONLY one force in physics, they are perhaps meAsures of different types of energy

Putting it in Quotation marks doesn't make it true, unless of course your actually quoting some one, an eminent physicist perhaps ?

 

[pdg]

Just for the purposes of discussion, and to show that I can google stuff too

Types of Forces

 

[WaterGal]

Have you looked at a system like this, that's designed to measure the speed, force, etc of your kick? The official distributor of adidas ZEMITA Martial Arts Supplies - Taekwondo, Karate, Judo, Jiu-jitsu, MMA

 

[jks9199]

What, really, are you trying to determine?

How "hard" a kick is? Do you need to measure the impact forces, the forces over time, penetration forces, or what? That'll shape how you can measure things. You might have something with a very high impact force measurement that produces very little movement of the target -- or something that drives through, moving the target but hardly feeling the intitial contact...

That's one of the problems I have with lots of the gadgets and "experiments" that measure the force of a punch or kick... They're like bullet "stopping power" -- really, meaningless without knowing a lot more. I can push you gently with the force needed to move a train, or dump that same force into a fractional second impact. Which one means more? All depends on what I'm trying to do, no? If I'm trying to push a car down the road, I want the force distributed over time, rather than instantly shaking or even crumpling the car. If I'm trying to knock you out -- yeah, I want that to happen in a fraction of a second. Even then -- placement matters, too...

 

[jobo]

Just for the purposes of discussion, and to show that I can google stuff too

Types of Forces

Well not very well it seems, they are different types of The same thing, like ballet and walking are different types of shoe, you can tell there all the same thing, as they are all measured in newtons, if it's not measured in Newtown it's not a force, if they are it is,

 

[pdg]

They're different types of force. Just like I said, which you said was wrong, then said I was wrong to say they're different because you say they're different.

You'd probably wear ballet shoes to go hiking if someone said they were unsuitable (well, you'd say you did, but change the subject if asked for evidence).

Then you'd proclaim how wrong that person was because you'd decided ballet shoes aren't suitable for hiking.

Bored now.

 

[dvcochran]

I can see why that might cause you problems, force is measured in Newtons not " g", g is mea unless unless you know the weight of what ever object it's attached to, if were you, I would take that back to Tandy

I don't think I have ever bought anything from Tandy. Not sure the still exist in the U.S. I did not need the accelerometer sensor for my BOM, just saw it on the webpage. The material cost alone is over 120K so I would go broke if I used a retail source.