system
August 26, 2011, 2:49pm
1
I have a Piezo Vibration Sensor - Small Horizontal and i have connected/wired it to my UNO as decribed in this tutorial: http://www.arduino.cc/en/Tutorial/Knock .
It works, measures and outputs data. But i would like it to output its data in decimals (ie 1.234) not just a whole number (ie 12). Using "float" adds the decimal in the output, like this 0.00 but all the numeric values after the decimal are a constant zero and never change. It's still outputting the whole number, but just with .00 on the end. How can i make the .00 be a reading aswell?
This is the code its running:
const float knockSensor = A0;
float sensorReading = 0;
void setup() {
Serial.begin(9600);
}
void loop() {
sensorReading = analogRead(knockSensor);
Serial.println(sensorReading);
delay(100);
}
Is there a way to do this.
thank you
something like ?
const float knockSensor = A0;
float sensorReading = 0;
void setup()
{
Serial.begin(9600);
}
void loop()
{
sensorReading = analogRead(knockSensor);
sensorReading = sensorReading / 100.0;
Serial.println(sensorReading, 2); // 2 digits
delay(100);
}
system
August 26, 2011, 4:54pm
3
You are awesome! Just what i was looking for
I added some threshold stuff back into the code, and it has increased the "sensitivity" so much.
const float knockSensor = A0;
const float threshold = 0.01;
float sensorReading = 0;
void setup()
{
Serial.begin(9600);
}
void loop()
{
sensorReading = analogRead(knockSensor);
sensorReading = sensorReading / 100.0;
if (sensorReading >= threshold) {
Serial.println(sensorReading, 2); // 2 digits
}
delay(75);
}
Thank you, thank you, thank you!
And add some duration since last knock ...
unsigned long lastTime = 0;
float threshold = 5.00;
void setup()
{
Serial.begin(9600);
Serial.println("Knocking monitor 0.1");
}
void loop()
{
sensorReading = analogRead(knockSensor) * 0.01; // combined two lines. note: multiply is faster than division
if (sensorReading >= threshold)
{
Serial.print(millis() - lastTime); // duration since last knock (or start)
lastTime = millis();
Serial.print("\t: ");
Serial.println(sensorReading, 2); // 2 digits
}
delay(75);
}
system
August 26, 2011, 5:15pm
5
robtillaart:
unsigned long lastTime = 0;
float threshold = 5.00;
void setup()
void loop()
That just prints "Knocking monitor 0.1" and never changes.
What is it supposed to do?
It should add a duration since last knock, maybe the threshold is too high ...
The title is just for checking the serial is working.
system
August 26, 2011, 6:09pm
7
Oh. I'll play around with it.
One last question... At the moment its just outputting/printing lines after lines of numbers. How could i get it to only output/print the highest value received, and update it when a higher value is made?
Thank you once again
just introduce a var that hold the maximum.
unsigned long lastTime = 0;
float threshold = 5.00;
float maxValue = 0.0;
void setup()
{
Serial.begin(9600);
Serial.println("Knocking monitor 0.1");
}
void loop()
{
sensorReading = analogRead(knockSensor) * 0.01; // combined two lines. note: multiply is faster than division
if (sensorReading >= maxValue)
{
maxValue = sensorReading;
Serial.print(millis() - lastTime); // duration since last knock (or start)
lastTime = millis();
Serial.print("\t: ");
Serial.println(sensorReading, 2); // 2 digits
}
if (millis() - lastTime > 30000UL) // no reading in 30 seconds, reset maxValue.
{
maxValue = 0.0;
}
// if (sensorReading >= threshold)
// {
// Serial.print(millis() - lastTime); // duration since last knock (or start)
// lastTime = millis();
// Serial.print("\t: ");
// Serial.println(sensorReading, 2); // 2 digits
// }
// delay(75);
}
