I've built a punch bag that tells you how hard you punch. Feedback needed.

[dejongajongjong]

Hi, For my A Level Design Tech project I've built a punching bag that tells the user (on a scale of 1 to 8, I wanted to use PSI but it would be too complex) how hard their punch is.
It works like this. The user punches the pad, which is filled with water, when they punch it the water gets displaced and travels up a tube. At the top of the tube is a funnel and glued onto the funnel is some rings which has a latex rubber membrane screwed in between the rings.
The rings inflate because of the water displacement and on top of the rings is a ratchet which is connected to the pendulum which gives a reading and tells the user how hard they punch. Simple.
I've attempted to make it look nice by wrapping some red self adhesive vinyl around it. It's attached to the wall using a makeshift wooden stand (I hate the stand btw, but it was necessary)

Anyway what do you think, does it look good, would you use it, what do you like/hate about it, Do you think you'd buy it it it would help your training?. Obviously you can't go in depth because you're not using it but give as critical an evaluation as you possibly can, Thanks.

Here's a photo of it btw:

[-FIGJAM-]

idea is good. deployment isnt tho.

I wouldnt want to hit a bag full of water thats handing off a wall for a couple of reasons.

1st, i see no training benefit
2nd i think id break my hand when i hit the wall.

There some feed back champ. Good idea, just need to rethink it some how.

[dejongajongjong]

The part that the user actually punches has a pad at the back to prevent them from breaking their hand when they hit the wall, But thanks

[-FIGJAM-]

the problem is not enough give.

a inch of wood and a bag of water, for some of the bigger hitters around wouldnt stop them from breaking their hand/wrist.

How much water can the bag hold?

I think it would be better, if you could build a stand for it to sit on, rather then using the wall. Something with a heavy base to stop it from tipping, and a sterdy base.

Just a thought, good luck tho.

[dejongajongjong]

I was actually thinking of building an adjustable metal stand for it however as the deadline drew closer I had neither the money nor materials

[Garland]

It's certainly an interesting protoype...I've seen several other machines that allegedly measure the force behind a hit, and all of them seem to have poor accuracy (that is they're measuring something that isn't actually the power of the hit, such as the rebound of a speed bag http://www.bhmvending.com/Amusements...ch_cabinet.gif)

There are also the things used by the whole "fight science" and "mythbuster" people...
Is there a machine that measures how hard you punch? can I make a simple one that mesures over 1000 pounds? - Yahoo! Answers

I don't know if there's a way to measure the difference between impact and impulse in a hit either...
Mechanic Impulse and Impact - full notes