- I want is to study the effect of arm angle (at the release point) on the pitch.
- Yes, I am talking about the EMG you mentioned.
- Accelerometers could be used for gesture recognition so I was thinking if the gesture of ball release could be detected with the accelerometer. As for an alternate the EMG could be used to see the particular muscle movements at the point of release and then it could be detected.

So you want to do is like the laboratory doing the sport research, I watched the video that they doing the research as how the angle of human body and arm will affecting the pitch speed, you may try an app for pitch speed, or using two electrode pads to detecting the resistance of skin and using the op amp voltage amplifier to amplifying the voltage, the Rf of amplifier is the resistance of skin, and using the uC as Arduino with ADC to reading the voltage changing during the ball is throws out, the uC will recording the data in memory or SD card.

 

So you want to do is like the laboratory doing the sport research, I watched the video that they doing the research as how the angle of human body and arm will affecting the pitch speed, you may try an app for pitch speed, or using two electrode pads to detecting the resistance of skin and using the op amp voltage amplifier to amplifying the voltage, the Rf of amplifier is the resistance of skin, and using the uC as Arduino with ADC to reading the voltage changing during the ball is throws out, the uC will recording the data in memory or SD card.

Exactly you have got it right, the electrode pad suggestion is good but will there be a significant change in the skin resistance at the point of release to differentiate it from the complete action. Also wouldn't I have to place the electrodes on the palm of the hand? because I can't do that due to the constraint of not placing anything on the ball or hand as I want to use it in matches. Would placing the electrodes somewhere on the wrist do the job?

 

Exactly you have got it right, the electrode pad suggestion is good but will there be a significant change in the skin resistance at the point of release to differentiate it from the complete action. Also wouldn't I have to place the electrodes on the palm of the hand? because I can't do that due to the constraint of not placing anything on the ball or hand as I want to use it in matches. Would placing the electrodes somewhere on the wrist do the job?

If this method just want to do the measuring then it's ok, if you want to do the detection as the ball hold in palm and the ball released from palm, this situation have to do a lots of measuring to get the data, and using the software to identify what data(number) was shown that the ball hold in palm and what data(number) was shown that the ball was released from palm, the electrode pad can be stick on two different places of the arm which the data(number) has big difference, of course, the convenience should be concerned when you stick them.

Here is a product to shown the Electrode Pad Placement Guide.

 

How can I specify an accelerometer when you are not defining the problem? What level of accuracy do you need? What are the other key variables of an accelerometer?
What values do those have to be for such a project?
Which manufacturers and part numbers are available that meet your price target (what is your price target)? That the distributors have in stock, that are big enough to be hand-soldered, that are small enough to fit on a wristband, that...

Do you see how this works?...

The price and the form of accelerometer are not an issue suppose we take the adxl345 which I have only used to detect the change in orientation. But since you suggested that at release the arm speed would change but how come would I get to that from an accelerometer.

 

I have not used OpenCV, but researched it for a project I was working on. I don't see it being used like the project you mentioned, but more like this. This isn't Open CV, but similar software.

 

If this method just want to do the measuring then it's ok, if you want to do the detection as the ball hold in palm and the ball released from palm, this situation have to do a lots of measuring to get the data, and using the software to identify what data(number) was shown that the ball hold in palm and what data(number) was shown that the ball was released from palm, the electrode pad can be stick on two different places of the arm which the data(number) has big difference, of course, the convenience should be concerned when you stick them.

Here is a product to shown the Electrode Pad Placement Guide.

Just one more question what factors make the output of these electrodes to change?

 

Just one more question what factors make the output of these electrodes to change?

I just make example as below, when our palm hold a ball and release the ball, the resistance of the muscle could be difference and how much difference that it should be through the measuring.

 

I just make example as below, when our palm hold a ball and release the ball, the resistance of the muscle could be difference and how much difference that it should be through the measuring.

View attachment 88088

I got it thanks hopefully I'll try it tomorrow and let you know.

 

I got it thanks hopefully I'll try it tomorrow and let you know.

That is the inverting voltage amplifier, if want to get a positive voltage then you need to adding another one the same amplifier to become a non inverting amplifier, or just using a non inverting amplifier.

 

That is the inverting voltage amplifier, if want to get a positive voltage then you need to adding another one the same amplifier to become a non inverting amplifier, or just using a non inverting amplifier.

Just wanted to know whether things like body sweat would significantly effect the resistance value? Because that could make my device to give false readings once the pitcher starts sweating.

 

Just wanted to know whether things like body sweat would significantly effect the resistance value? Because that could make my device to give false readings once the pitcher starts sweating.

Your concerned is right, when the skin has more sweat and then the resistance of skin will be more less, I think the resistance between two electrode pads should be including the skin and the blood(there is water in it), I was modified the inverting amplifier to non inverting amplifier, and the values of resistors just for reference. (The circuit in #27 missed the input resistor and I added in)

 

If you want to try the electrode pads, you may stick one on the back of the palm and another one on the back of the arm or close to the shoulder.