Measuring speed at impact between two objects....

[Dad helping out]

I'm working with my son on a problem that we are looking for some guidance on....have no experience in electronics....but are both really looking to learn.

In a nutshell....assume you have two round objects....around the size of a racquetball...we want to have a way of putting electronics inside the sphere that would measure the impact between the two objects upon collision....gather data like speed, direction, Any other variables you can think of, etc....and then view the data on a smart phone.

Obvious issues....what would we need on the inside....how would we build it so the electronics would survive getting knocked around and then how would we transfer the data they capture to the phone.....tethered and wireless options are very welcome.

As a final request....if anyone could include their anticipated cost of their solution....that would be great.

Thanks in advance,
Dad helping son.

 

[chopnhack]

Great idea, but difficult first project!

A simpler approach would be to photograph or video record the two spheres colliding against a background that you can take measurements against - like the kind you see in crash tests:

http://www.canaralighting.com/automative_crash.html
http://www.canaralighting.com/automative_crash.html
See the yellow 'ruler'

Knowing the initial speed and weight of the spheres you can mathematically solve for the rest using some physics.

To your original question, perhaps others can come by and be of more assistance on small scale telemetry.

 

[Dad helping out]

Great idea, but difficult first project!

A simpler approach would be to photograph or video record the two spheres colliding against a background that you can take measurements against - like the kind you see in crash tests:

http://www.canaralighting.com/automative_crash.html
See the yellow 'ruler'

Knowing the initial speed and weight of the spheres you can mathematically solve for the rest using some physics.

To your original question, perhaps others can come by and be of more assistance on small scale telemetry.

Thanks for the reply and the good suggestion...however the project has to have the measurement come from within the object doing the collision.

 

[chopnhack]

That is an interesting wrinkle ;-)

Well, if you make the sphere bigger, you can use an arduino with some add on shields like this.

 

[Merlin3189]

I'm not sure I have much to contribute beyond agreeing that it sounds a very difficult task, but can I ask why? If your overriding objective is to know this data about the objects, why do you think the best way is to put the sensors inside the balls? It seems like an arbitrary and unnecessary additional difficulty.
If you want to know position and speed, then the sensors have to interact with objects outside of the sphere (the frame of reference) as these properties are not absolutely defined. In which case it might be easier to put the sensors in the reference frame rather than in the object.
Magnitude of acceleration you can measure from inside the sphere, but the forces you measure would need to be referred to the external frame if you required direction and sense.

Early Earth satellites did not have as sophisticated electronics as modern satellites. They did not calculate their own positional parameters, but sent out a reference signal that Earth based stations could detect and use to calculate position and velocity. A similar idea for your spheres would still be a very difficult project, but should be easier with the sensors and computers outside and fixed.

 

[davenn]

Sorry to also sound negative, But I agree with chopnhack and merlin
You need to learn to crawl before you walk and walk before you run

A project like this is just way way too complex for someone already admitting to having no experience
in electronics
your main issues would be with getting circuits miniature enough to fit inside the small balls
even this would provide electronics specialists with access to hi tech labs, a major challenge

honestly .....
step back and consider some more realistic projects to learn about electronics on

Dave

 

[Merlin3189]

I just realised you commented earlier,

..however the project has to have the measurement come from within the object doing the collision.

If the object does not have to be something like a raquett ball, you'd be on to a more practical proposition measuring the impact of a couple of trucks (models!) colliding. Maybe even have them on tracks. More space to put stuff, one dimension to measure, wheels providing contact with a reference surface.

 

[Dad helping out]

Hmmmm....not of to a great start.
While I do appreciate the thoughts on other ways to get at this.....I think it's best to assume that the project as described is the way we have to proceed.....so that being said...all open to suggestions.

 

[Dad helping out]

That is an interesting wrinkle ;-)

Well, if you make the sphere bigger, you can use an arduino with some add on shields like this.

.....go on.

 

[Dad helping out]

Sorry to also sound negative, But I agree with chopnhack and merlin
You need to learn to crawl before you walk and walk before you run

A project like this is just way way too complex for someone already admitting to having no experience
in electronics
your main issues would be with getting circuits miniature enough to fit inside the small balls
even this would provide electronics specialists with access to hi tech labs, a major challenge

honestly .....
step back and consider some more realistic projects to learn about electronics on

Dave

Dave,
What's the most limiting factor here.....the size of the container....the measurement of data upon impact....the wireless transmission of data....something else....if you had to figure something out.....where would you start to get a basic prototype....we are excited to solve a problem we have in our head and don't want to give up so soon.

 

[chopnhack]

I agree that you should not give up too soon - much can be done with dedication! But you may spend more than a year on the project.
Do you have the time and resources to do such?
Is this a project with a hard deadline?
Academic or for pleasure?
I think that you should lay all the cards on the table for folks to assist you with something that is fairly complex!

My thoughts on the arduino are that since its essentially a small computer, you have the ability to capture the data and then download it later - that satisfies one component of your requirements. Next, the add on shield I linked you to is an accelerometer and gyroscope - this would give you positional and 'g' force data. Couple that with a time function, which the arduino should be able to natively provide. As for accessing the data on a smartphone, they do make arduino shield bluetooth units, do a search on ebay and you can find them rather inexpensively.

This is a starting point. I think if you are serious about this project you will need to review and specify your requirements more thoroughly and match that against skill sets that you have or can acquire and see what is lacking. From know to unknown!

FYI - I am a novice, I have given you the broadstrokes of how I would approach this problem - others who are more experienced could possibly make this entire project smaller by using a PIC or other μ-processor and program it with your specific needs thus reducing size and weight of board (ridding it of unneeded I/O, etc.) but that is beyond my knowledge base.

Good luck and keep us all posted, we would love to help, where we can!

 

[davenn]

Dave,
What's the most limiting factor here.....the size of the container....the measurement of data upon impact....the wireless transmission of data....something else....if you had to figure something out.....where would you start to get a basic prototype....we are excited to solve a problem we have in our head and don't want to give up so soon.

All of the above
I'm not telling you to "give up" .... I just need you to understand the complexity of what is involved
Every week on this and other forums we see your style of post
people think that can throw a couple of wires and components together and make some amazing
device that would take the Apple company years of research and development

chopnhack has covered much of it in my absence

The most limiting factors in no particular order ....
you lack of knowledge/skills in electronics ( would you expect to become an interpreter at the united nations if you didn't know how to speak a bunch of different languages ?)
its the same here there are different skillsets needed ... eg. design, construction, programming
Size .. definitely .... you will probably need to start with a prototype much larger than you wanted
and as time goes by work on ways to reduce its size
do you know how to write and program microprocessors ? no? then you need how to learn that
do you have any soldering skills in miniature electronics ?
who will design your circuit board layouts and make them for you ?

This comment from chopnhack really is your starting point ....

This is a starting point. I think if you are serious about this project you will need to review and specify your requirements more thoroughly and match that against skill sets that you have or can acquire and see what is lacking. From know to unknown!

define and find out about what sensors you need
learn what is needed to interface them to a microprocessor
determine which communications method you want to use between the remote device and the phone
learn what is needed to achieve that and how it goes together
Do you know how to write apps for the phone to receive the data and convert it into meaningful on screen display ?

these are just some of the challenges ahead for you

Dave

 

[BobK]

It is not just the electronics that make this project difficult. It is the physics as well. In a closed system (no info coming in from outside) you cannot sense velocity or direction. The only thing you can sense is acceleration. Now, if you know your position and velocity at the start, you can sense acceleration on 3 axes, and integrate it twice to determine the new velocity and position. But the trouble is that errors will accumulate and your data will be invalid, probably within seconds. In a rolling ball the acceleration will be changing constantly. Systems that do this need to use gyroscopes as well as accelerometers and the math to combine the data and get accurate results would be quite difficult for me, even though I have a bachelors in Physics and a Masters in Computer Science.

And if this isn't enough, the mechanical design is also daunting. Assuming you want to balls to roll true, like a billiard ball, not like a Mexican jumping bean, the mass must be distributed equally around the sphere. With the embedded electronics, this would seem difficult at best.

In summary, if I were offered $1M to either create the system you want or to design a 32-bit digital computer from scratch in 1 year, I would opt for the latter.

Bob