force gauge or accelerometer?

[intense]

punch force gauge

Hi, im trying to make a digital measuring device that displays the force of a punch.

what would best fit my needs? A force gauge or an accelerometer?

links would be great, im a noob.

oh and first post, glad to be here.

 

[pakitos]

punch accelerometer

the accelerometer will be effected not only with the punch but also with displacement or tilting.
So the force gauge will be more suitable.
Also piezoelectric sensors can be used. These sensors output a voltage upon impact but output only a very small voltage when in motion.
are you using an MCU?

 

[mzypt]

I'm also interested to build something similar. The idea is to attach a force gauge directly to surface of punch bag. MCU (Atmega) will function as a standalone data recorder or interface to laptop data acquisition system. Maybe latter is easier.

What is needed
--- The sensor itself. Piezoelectric sensor maybe suits best
--- MCU. I was thinking just simple Atmega MCU to interface sensor to laptop
--- Software to laptop. A graph to see force over time.

Any better ideas to build a simple system?

 

[haker_fox]

Re: punch force gauge

A force gauge or an accelerometer?

Hi! If you will be using the accelerometer a reduced mass of your fist is needed. In accordance with the 3rd Newton's law: F = m * a.

 

[hameeds01]

force guage is a better option & simple

 

[mzypt]

Hi,

Please explain a bit more about force qauge? I thought that piezoelectric sensor IS a simple force gauge. It outputs a small voltage proportional to impact on it's surface.

What obout resistive sensors...like flexisensor I found from website

The FlexiForce single element force sensor acts as a force sensing resistor in an electrical circuit. When the force sensor is unloaded, its resistance is very high. When a force is applied to the sensor, this resistance decreases. The resistance can be read by connecting a multimeter to the outer two pins, then applying a force to the sensing area. In the image below, the plot shows both the Force vs. resistance and Force vs. conductance (1/R). Note that the conductance curve is linear, and therefore useful in calibration.

Added after 8 minutes:

I'm thinking of using Arduino card as an interface to PC.

Sensor--->Atmega --->Laptop

Any idea of software I can use to show sensor output as a graph on laptop display?

 

[pakitos]

flex sensor is a resistor which reacts to bending (resistance changes) so i think force gauges are still better

 

[javier53]

I think that the force gauges are not specific to measure a punch because these devices are perfects to measure incremental forces and a punch, is unit measure of 0,5 or 1 second.

I think that are better the accelerometers. In particular, this PCE-VDL accelerometer with Data logger would be ideal for this purpose because his measurement quota is 64 values per second up to one value every 5 minutes in the impact mode.

The three-axis impact data logger PCE-VDL used to measure both impact and vibrations is a compact data logger for G force with a high resolution and powered by batteries. This three-axis impact data logger PCE-VDL can be easily programmed through the software to the automatic registration of three-axis impact signals up to 500 g. The data logger PCE-VDL is able to measure and record G force as the peak acceleration during a period of time predefined by the user. Measurement values are stored in a non-volatile memory (349.525 measurement values in each axis).