Hello everyone, and thanks for your time and feedbacks.
I'm attaching a picture of the piezo I'm using. I don't have any electronic specification for it.
Good question I'm not setting a sampling rate, so I assume using the default one. Where can I find / modify such setting ?
Unfortunately, averaging is not an option, as user is requested to hit the surface once.
I'm using 1M Ohm resistor in parallel with the piezo, and later, added a 50v 1uF cap, also in parallel, and appearently it smoothes the signal, and it is somehow easier to detect the peak, at the cost of a longer time to reach zero again.
Thanks again for the replies, and apologies for my late reply.
Apologies, didn't get home sooner to get the code and schematics, here they are:
// Define the analog input pin
const int analogPin = A0;
// Variables to store peak values
int peakValue = 0;
int previousValue = 0;
int descendingCount = 0; // Counter for consecutive descending reads
int maxValue = 50;
int maxValueNormalized = 100;
int sensorValue;
String piezoString;
char incomingCharacter;
bool debugMode = false;
bool descending = false; // Flag to track if the value is descending
unsigned long peakReturnTime = 0; // Time of the last peak value return
void setup() {
// Initialize serial communication
Serial.setTimeout(25);
Serial.begin(9600);
}
void loop() {
// Read the analog value
HandleSerial();
maxValue = constrain(maxValue, 0, 1000);
sensorValue = analogRead(analogPin);
sensorValue = constrain(sensorValue, 0, maxValue);
sensorValue = map(sensorValue, 0, maxValue, 0, maxValueNormalized);
ReturnPiezoValue();
}
void ReturnPiezoValue() {
if (debugMode) {
Serial.print(maxValueNormalized);
Serial.print(",");
Serial.println(sensorValue);
} else {
// Check if the value is a new peak
if (sensorValue > peakValue) {
peakValue = sensorValue;
descending = false; // Reset the descending flag
}
// Check if the value is descending
if (sensorValue < previousValue) {
descendingCount++;
if (descendingCount >= 5) {
descending = true;
}
} else {
descendingCount = 0;
}
// Check if the value is descending and print the peak value
if (descending) {
// Print the peak value if it's not zero and reset it
if (peakValue > 0) {
if (millis() - peakReturnTime >= 1000) {
piezoString = "p" + String(peakValue);
Serial.println(piezoString);
peakReturnTime = millis();
}
}
peakValue = 0;
descending = false; // Reset the descending flag
descendingCount = 0; // Reset the descending counter
}
// Store the current value for comparison in the next loop iteration
previousValue = sensorValue;
}
}
void HandleSerial() {
while (Serial.available() > 0) {
incomingCharacter = Serial.read();
switch (incomingCharacter) {
case 'd':
debugMode = !debugMode;
break;
case 'a':
maxValue += 10;
Serial.print("maxVal = ");
Serial.println(maxValue);
break;
case 'z':
maxValue -= 10;
Serial.print("maxVal = ");
Serial.println(maxValue);
break;
}
}
}
I have made my own version based on that topic but I must say that I have had an defect in my analog input reading after one night/day with unpowered Seeeduino board and connected piezo wiring. I had done a long test of running board and connected piezo continuesly for some days without problems. I had to think about a comment from @Wawa that the input is max Vcc + 0.5V... maybe I add a diode from analog input to Vcc to catch this?
I keep the lowest and the highest reading and use the substraction as 'sensorresponse'.
My code:
<code>
// these constants won't change:
const int piezoSensor = A5; // the piezo is connected to analog pin 5
// these variables will change:
long int sensorReading = 0; // variable to store the value read from the sensor pin
long int sensorReadingLow = 1024; //max value
long int sensorReadingHigh = 0;
int counter = 0;
void setup()
{
Serial.begin(115200); // use the serial port
}
void loop() {
counter++;
// read the sensor and store it in the variable sensorReading:
sensorReading = analogRead(piezoSensor);
if (sensorReading > sensorReadingHigh) {
sensorReadingHigh = sensorReading;
}
if (sensorReading < sensorReadingLow) {
sensorReadingLow = sensorReading;
}
if (counter > 10000 ) {
Serial.print("Sensor Reading = ");
Serial.print(sensorReading);
Serial.print(" Sensor Reading range = ");
Serial.println(sensorReadingHigh - sensorReadingLow);
counter = 0; //reset
sensorReadingHigh = 0;
sensorReadingLow = 1024; //max value
}
}
</code>
I'm not setting a sampling rate, so I assume using the default one. Where can I find / modify such setting ?
