Why is analogRead() returning zero all the time?

hi all,

i'm doing stupid here i've been @ hour , brain hurts. if can, please shed little sanity! problem is, analogread() returning 0 on both pins i'm using, if *deliberately* remove sensor attached pin , supply voltage.

the code designed work maxbotix ez1 sonars (in case you're wondering!).

thanks!

code: [select]


int sonarwarmupdelay = 250;             // ms delay after powerup before first reading available
int sonardelaybetweenpings = 25;       // ms wait between readings
int sonarreadings = 5;              // number of readings obtain (and average) pad results

// configure power output
#define totalsonars 2                  // total number of sonar sensors being polled
int pwr[] = { 6, 7 };                  // power pins
int son[] = { 1, 0 };                  // corresponding data pins pwr[] array (eg. "sonar operated on pwr pin 7 read on analog pin 0)

// store current sensor readings
int vals[totalsonars];

void setup() {
 
 // configure serial
 serial.begin(9600);
 
 // turn off sonars start
 for (int i; < totalsonars; i++) {
  pinmode(pwr[i], output);
  pinmode(son[i], input);
  digitalwrite(pwr[i], low);  
 }
 
}

void loop() {      
     for (int i; < totalsonars; i++) {                
       vals[i] = getsonarreading(pwr[i], son[i]);            
     }      
}      

int getsonarreading(int pwr, int sensor) {
     // powerup sonar
     int val = 0;
     digitalwrite(pwr, high);
       delay(sonarwarmupdelay);            // wait specified time before obtaining reading
     for (int i; i<=sonarreadings; i++) {
           val += analogread(sensor);
           delay(sonardelaybetweenpings);
     }
       digitalwrite(pwr, low);
     val = val / sonarreadings;
     return val;
}



asking obvious - using analogue input pin?
the analogue pins separate digital ones, , don't need

pinmode(son, input);

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