Guys thanks for the input I understand that this would work but I am actually constrained by the design of the device which has to be an arm band and placing a potentiometer on the shoulder blade would become exposed. That is the reason why I am looking for a solution (tilt sensors etc) that might work by placement on the upper or forearm. So, if you guys have had any experience working with these things.

 

Yes, I have worked with digital compasses, inclinometers and tilt sensors. They work well if there are no movement or accelerations other than the axis being measured.

Imagine this:
Hang a weight from a string from your hand. As long as you hold your arm still the weight will point to the ground (gravity). The second you start to swing your arm, the centrifugal force will overwhelm the power of gravity and the weight will no longer point to the ground (especially when you want it to). This will also happen to an inclinometer or an accelerometer.

 

Is calibration allowed before each use? If so, maybe a unit that measures the distance to the floor would work. An ultrasonic range finder comes to mind.

 

@RichardO
Calibration could be done but then again the placement of the ultrasonic sensor would be a challenge because the arm rotation would cause the sensor to may be not face the ground at the point of concern.

 

I'm assuming that since the device must be portable that the location where the measurements are taken may be variable as well. Otherwise if you cannot video the skipping, you cannot control (to some extent) the location.

I am thinking of a set where the measurements are taken, perhaps built in a warehouse. The walls are painted in a grid. Thence, the person wears the camera on his forearm.

I write this not as a practical solution, but to stimulate the mind.

 

@djsfantasi
That would be really interesting but then again the location is not under control.