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Signal Conditioning
#What's Signal Conditioning
Signal Conditioning is one process before and after signal processing. Before processed in MCU(Arduino), signals acquired from sensors must be conditioned to meet the demand of the MCU . Before used to control the devices, signals processed by MCU also must be conditioned to meet the demand of power system.
#Example 1
Generally, the output of sensors is resistance. To become an available input for Arduino, it's important to build a circuit to convert the change of resistance to the change of voltage(lower than 5V). It's better to add a resistor whose resistance is close to that of the sensor.
#Example 2
As the only function of MCU is processing the signal, buffer, as a signal conditioner, is necessary to drive objects/devices(like LEDs) with power system, especially high power loads.
#Combined Examples
Through combining Ex1 and Ex2, we get a complete project about using photoresistance to control LEDs.
Codes in Arduino:
//Using photoresistance to control 2 LEDs.
const int VccPin = A9;
const int analogInPin = A5; // Analog input pin that the potentiometer is attached to
int sensorValue = 0; // value read from the pot
int outputValue = 0; // value output to the PWM (analog out)
int ledPin = 9;
void setup() {
}
void loop() {
analogWrite(VccPin,255);
// read the analog in value:
sensorValue = analogRead(analogInPin);
// map it to the range of the analog out:
outputValue = map(sensorValue, 0, 1023, 0, 255);
if(outputValue>=100)
analogWrite(ledPin, 255);
else
analogWrite(ledPin, 0);
// wait 2 milliseconds before the next loop
delay(2);
}