Piezoelectric Insole: How to Convert Voltage Output to Digital Signal for MATLAB?

Hi Guys
I hope you can help me.
First of all, I´m not an electrical engineer. So, I probably don’t understand short terms and very complicated words etc
I´m doing my master’s degree in biomedical engineering and therefore just have a bit of knowledge in electronics since my bachelor were in physiotherapy and not engineering.
For my project, I need to build an insole which can detect maximal pressure and duration of the pressure applie, when walking on it.
I´m thinking of using piezo electrical elements to detect the pressure by producing a voltage. I would like to convert the voltage to a signal, and then import it to Matlab.
I´m wondering how I get the voltage converted to a signal and record it. Do you have any ideas on how the circuit should look like and which components I should use?
Best regards
Kasper - Denmark

You'll want to research analog to digital converters, which will convert a voltage to a digital representation (1s and 0s) that can be read by a microprocessor.

Another alternative is using pulse-width modulation, which will convert your voltage into a string of pulses whose width is proportional to the voltage, and can be reliably transmitted over a distance to a computer using wired or wireless technology.

You may want to hook up with an engineering student to get this done quickly.

you can try feeding the piezo element voltage output to a VCO (voltage controlled oscillator) and then mapping the frequency output to the corresponding force.

I am not sure but may it help you
Pl. see the below link
http://www.ece.uvic.ca/~elec499/2004b/group17/MDA.htm
In the above link, there is an circuit which is for sensing the pressure. It will convert the sensor output into voltage output.
Option 1 (develop hardare)
For maximum voltage you can put a small capacitor and diode after the instrumentation amplifier(in the circuit in link). which will store your maximum voltage i.e. maximum pressure.
Now use a ADC 0804 or other to convert it into a 8 bit digital signal. see link below.
http://www.circuitstoday.com/digital-temperature-sensor

Now for time duration, make a astable circuit using a 555 IC whose reset is connected with your output voltage. Now count the pulses of 555 using 4017B counter.


Option 2 (write program in MATLAB)
Simply use a ADC 0804 at the o/p of instrument amplifier as in the link
(http://www.ece.uvic.ca/~elec499/2004b/group17/MDA.htm)
(http://www.circuitstoday.com/digital-temperature-sensor)
and send it to PC where record it after each 10ms. And write a software programme to find out the maximum pressure and its duration.