Servo code

I am hoping to finish up my dust collector project today. I am having trouble tweaking the servos. My question is, what do the numbers represent that is telling the servos how far to open and close? I copied a project that I saw on youtube and used the code that he had used.

 * This code is for the project at 
 * All of the components are list on the url above.
This script was created by Bob Clagett for I Like To Make Stuff
For more projects, check out and modified by Terry Neal

Includes Modified version of "Measuring AC Current Using ACS712"

Parts of this sketch were taken from the keypad and servo sample sketches that comes with the keypad and servo libraries.

#include <Wire.h>
#include <Adafruit_PWMServoDriver.h>
// called this way, it uses the default address 0x40
//Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver();
// you can also call it with a different address you want
Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver(0x41);

// Depending on your servo make, the pulse width min and max may vary, you 
// want these to be as small/large as possible without hitting the hard stop
// for max range. You'll have to tweak them as necessary to match the servos you
// have!
//servos used DS3218mg
// our servo # counter
uint8_t servoCount = 6;
uint8_t servonum = 0;

const int OPEN_ALL = 100;
const int CLOSE_ALL = 99;

boolean buttonTriggered = 0;
boolean powerDetected = 0;
boolean collectorIsOn = 0;
int DC_spindown = 3000;
//allow vacuum system to run after tool is turned off
const int NUMBER_OF_TOOLS = 4;
const int NUMBER_OF_GATES = 4;

String tools[NUMBER_OF_TOOLS] = {"Spindle sander","Belt sander","Miter saw","Router"};
int voltSensor[NUMBER_OF_TOOLS] = {A0,A1,A2,A3};
long int voltBaseline[NUMBER_OF_TOOLS] = {0,0,0,0};

//Set the throw of each gate separately, if needed
int gateMinMax[NUMBER_OF_GATES][2] = {
  /*close, open*/
  {230,375},//Spindle sander
  {195,410},//Belt Sander
  {250,400},//Miter saw

//keep track of gates to be toggled ON/OFF for each tool


const int dustCollectionRelayPin = 11;
const int manualSwitchPin = 12; //for button activated gate, currently NOT implemented

int mVperAmp = 100; // use 100 for 20A Module and 66 for 30A Module
double ampThreshold = .20;

double Voltage = 0;
double VRMS = 0;
double AmpsRMS = 0;

//button debouncing
int state = HIGH;      // the current state of the output pin
int reading;           // the current reading from the input pin
int previous = LOW;    // the previous reading from the input pin

// the follow variables are long's because the time, measured in miliseconds,
// will quickly become a bigger number than can be stored in an int.
long time = 0;         // the last time the output pin was toggled
long debounce = 200;   // the debounce time, increase if the output flickers

void setup(){ 
  pwm.setPWMFreq(60);  // Default is 1000mS
 //record baseline sensor settings
 //currently unused, but could be used for voltage comparison if need be.
  for(int i=0;i<NUMBER_OF_TOOLS;i++){
    voltBaseline[i] = analogRead(voltSensor[i]); 

void loop(){
  // use later for button debouncing
  reading = digitalRead(manualSwitchPin);

  if (reading == HIGH && previous == LOW && millis() - time > debounce) {
    if (state == HIGH){
      state = LOW;
     buttonTriggered = false;
    } else{
      state = HIGH;
     buttonTriggered = true;
    time = millis();    
  previous = reading;
   //loop through tools and check
   int activeTool = 50;// a number that will never happen
   for(int i=0;i<NUMBER_OF_TOOLS;i++){
      if( checkForAmperageChange(i)){
        activeTool = i;
      if( i!=0){
          activeTool = 0;
  if(activeTool != 50){
    // use activeTool for gate processing
    if(collectorIsOn == false){
      //manage all gate positions
      for(int s=0;s<NUMBER_OF_GATES;s++){
        int pos = gates[activeTool][s];
        if(pos == 1){
        } else {
 //delay added to allow gates to open before vacuum system comes on
  } else{
    if(collectorIsOn == true){
boolean checkForAmperageChange(int which){
   Voltage = getVPP(voltSensor[which]);
   VRMS = (Voltage/2.0) *0.707; 
   AmpsRMS = (VRMS * 1000)/mVperAmp;
   Serial.print(tools[which]+": ");
   Serial.println(" Amps RMS");
    return true;
    return false; 
void turnOnDustCollection(){
  collectorIsOn = true;
void turnOffDustCollection(){
  collectorIsOn = false;
float getVPP(int sensor)
  float result;
  int readValue;             //value read from the sensor
  int maxValue = 0;          // store max value here
  int minValue = 1024;          // store min value here
   uint32_t start_time = millis();
   while((millis()-start_time) < 500) //sample for 1 Sec
       readValue = analogRead(sensor);
       // see if you have a new maxValue
       if (readValue > maxValue) 
           /*record the maximum sensor value*/
           maxValue = readValue;
       if (readValue < minValue) 
           /*record the maximum sensor value*/
           minValue = readValue;
   // Subtract min from max
   result = ((maxValue - minValue) * 5.0)/1024.0;
   return result;

void closeGate(uint8_t num){
  Serial.print("closeGate ");
  pwm.setPWM(num, 0, gateMinMax[num][1]);
void openGate(uint8_t num){
  Serial.print("openGate ");
    pwm.setPWM(num, 0, gateMinMax[num][0]);
    pwm.setPWM(num, 0, gateMinMax[num][0]-5);

The numbers in the gateMinMax array are just numbers (between 0 and 4096) that represent where the servo moves to. If you want to change the way a servo works just fiddle with its numbers until it does what you want it to.

It would be possible to write a program to calibrate the range of numbers against the positions they give with your particular servos but it's hardly worth the effort. Just tweak them and see what the effects are.