Insole Pressure Sensor Matrix

Community Projects
1

Hello Everyone,

I would like to create a shoe insole with several pressure sensors embedded in it to measure the foot pressure distribution as we walk and run and I need some serious help.

a) What type of pressure sensors would I need? What are the smallest pressure sensor I can find so I can place enough of them inside the insole?

b) If, say, 20 pressure sensors were used, how would we connect them to some small Arduino microcontroller to capture and record the pressure data from each sensor? I would need 20 channels which seems a lot. Would the Arduino need a SD card as well?

Thanks,

Antennaboy

2

Consider a force sensitive resistor: https://www.sparkfun.com/products/9375

You will need one ADC pin per sensor, for a maximum of eight with some Arduinos.

3

Thank you.

That force sensor is 0.5" in diameter. I wish it was smaller so I can have more sensors embedded inside the insole.

What if I want to use more than 8 sensors? Do I need to look for a microcontroller with more than 8 pins?

4

I would not be surprised at all if smaller ones are to be found!

One ADC channel per sensor.

5

Thanks jremington!

Beginner question: a ADC is an analog to digital converter. Why does the signal need to be converted to digital if we are trying to record the analog pressure signals from each point on the insole?

6

Computers are digital devices. Hence the “converter” in the ADC.

7

Analog can be perceived as something like 0-10 VDC or 0-1000 ohm resistance or several other things.

The Analog to digital convertor changes that to a numeric value (digital) like 0-1023 or 0-4095.

From that point, you can scale the values to whatever units you like.

Now you can record the signal values from your analog input or do anything else you would like.