用ArduinoNano，做个简易金属探测器

金属探测器，大家估计会喜欢吧？

如下是电路图和源码，大家可以按此制作DIY~

BOM清单：

• R1=330Ω，resistor

• R2=1kΩ，resistor

• C1=10nF，ceramic capacitor

• D1=1N4148，diode

• BUZ1=Buzzer

• LED1=5mm，any color LED

• Arduino UNO Board or equivalent

成品图：

实现代码如下：

#define vinPin A5#define buz 9#define pulsePin A4
#define led 10
long sumExpect=0; //running sum of 64 sums long ignor=0; //number of ignored sumslong diff=0; //difference between sum and avgsumlong pTime=0;long buzPeriod=0; 
void setup() { Serial.begin(9600); pinMode(pulsePin, OUTPUT); digitalWrite(pulsePin, LOW); pinMode(vinPin, INPUT); pinMode(buz, OUTPUT); digitalWrite(buz, LOW); pinMode(led, OUTPUT);}
void loop() { int minval=1023; int maxval=0; long unsigned int sum=0; for (int i=0; i<256; i++) { //reset the capacitor pinMode(vinPin,OUTPUT); digitalWrite(vinPin,LOW); delayMicroseconds(20); pinMode(vinPin,INPUT);    applyPulses(); //read the charge of capacitor int val = analogRead(vinPin); //takes 13x8=104 microseconds minval = min(val,minval); maxval = max(val,maxval);    sum+=val; long unsigned int cTime=millis(); char buzState=0; if (cTime<pTime+10) { if (diff>0) buzState=1; else if(diff<0) buzState=2; } if (cTime>pTime+buzPeriod) { if (diff>0) buzState=1; else if (diff<0) buzState=2; pTime=cTime; } if (buzPeriod>300)    buzState=0; if (buzState==0) { digitalWrite(led, LOW); noTone(buz); } else if (buzState==1) { tone(buz,2000); digitalWrite(led, HIGH);    } else if (buzState==2) { tone(buz,500); digitalWrite(led, HIGH); } } //subtract minimum and maximum value to remove spikes sum-=minval;   sum-=maxval; if (sumExpect==0) sumExpect=sum<<6; //set sumExpect to expected value long int avgsum=(sumExpect+32)>>6; diff=sum-avgsum; if (abs(diff)<avgsum>>10) { sumExpect=sumExpect+sum-avgsum; ignor=0; } else ignor++; if (ignor>64) { sumExpect=sum<<6; ignor=0; } if (diff==0) buzPeriod=1000000; else buzPeriod=avgsum/(2*abs(diff)); }
void applyPulses(){ for (int i=0;i<3;i++) { digitalWrite(pulsePin,HIGH); //take 3.5 uS delayMicroseconds(3); digitalWrite(pulsePin,LOW); //take 3.5 uS delayMicroseconds(3); }}