Velostat Pressure Mapping Matrix Troubleshoot
Budget: ₹1,500 – ₹12,500 INR
I have developed a Velostat-based pressure mapping matrix. The setup uses 9 copper columns on the top layer and 9 copper rows on the bottom layer of the Velostat sheet. The column lines are connected to a CD74HC4067 multiplexer (C0–C8) with 10 kΩ pull-down resistors.
The controller used is an Arduino Mega.
MUX signal → A0
MUX select lines (S0–S3) → digital pins 2, 3, 4, 5
Enable → GND
VCC → 5 V
Copper rows → digital pins 22–30
This setup worked perfectly. I was able to read the data and plot a proper pressure map using Python.
However, the problem started when I rebuilt the exact same circuit with a different Velostat sheet. This time, the Arduino serial monitor shows only zeros, with no pressure response. When I removed the pull-down resistors, I started getting random values even without applying pressure.
To debug this, I tried:
Changing resistor values
Using pull-up instead of pull-down
Verifying all circuit connections
Replacing Velostat sheets
Testing with ESP32 instead of Arduino Mega
Using shift registers
Changing copper electrodes
Mounting and remounting the Velostat sheets
After all this, I suspect that each Velostat sheet has different electrical properties (base resistance, sensitivity, hysteresis), though I am not fully certain.
I am looking for a problem solver who has real experience with Velostat / FSR / pressure-mapping matrices and understands why this happens and how to design a stable, repeatable solution.
The controller used is an Arduino Mega.
MUX signal → A0
MUX select lines (S0–S3) → digital pins 2, 3, 4, 5
Enable → GND
VCC → 5 V
Copper rows → digital pins 22–30
This setup worked perfectly. I was able to read the data and plot a proper pressure map using Python.
However, the problem started when I rebuilt the exact same circuit with a different Velostat sheet. This time, the Arduino serial monitor shows only zeros, with no pressure response. When I removed the pull-down resistors, I started getting random values even without applying pressure.
To debug this, I tried:
Changing resistor values
Using pull-up instead of pull-down
Verifying all circuit connections
Replacing Velostat sheets
Testing with ESP32 instead of Arduino Mega
Using shift registers
Changing copper electrodes
Mounting and remounting the Velostat sheets
After all this, I suspect that each Velostat sheet has different electrical properties (base resistance, sensitivity, hysteresis), though I am not fully certain.
I am looking for a problem solver who has real experience with Velostat / FSR / pressure-mapping matrices and understands why this happens and how to design a stable, repeatable solution.