Measuring capacitor discharge curve issue

hi there,

i need measure few points on discharge curve of capacitor using arduino.  how looks code:

code: [select]


if(state == 2)
   {
     digitalwrite(rele1, low);
     if(u0 == 0)
     {
       u0 = (5.0/1023.0*(double)analogread(a13))*3.0;
       lcd.setcursor(6,0);
       lcd.print(u0);
     }
     if(akt == 0)
     {
       akt = millis();
     }
  //time 1   
     u1 = (5/1023*analogread(a13))*3;
     lcd.print(u1);
     if(u1 <= 9.0 && t1 == 0)
     {
       t1 = ((double)millis()-(double)akt)/1000.0;
       
       lcd.setcursor(-4,2);
       lcd.print(t1);
     }
//time 2
     u2 = (5/1023*analogread(a13))*3;
     if(u2 <= 6.0 && t2 == 0)
     {
       t2 = (millis()-akt)/1000.0;
       lcd.setcursor(1,2);
       lcd.print(t2);
     }
//     time 3
     u3 = (5/1023*analogread(a13))*3;
     if(u3 <= 3.0 && t3 == 0)
     {
       t3 = (millis()-akt)/1000.0;
       lcd.setcursor(6,2);
       lcd.print(t3);
     
     }


i try measure voltage, , if voltage falls below example 9 volts need record time.

if print these 3 times on lcd show 0.00 v.

quote

i try measure voltage, , if voltage falls below example 9 volts need record time.

if voltage doesn't fall below 5.0v, you'll fry arduino.

quote

if print these 3 times on lcd show 0.00 v.

since values time, it's unusual see time expressed in volts. part of world that?

post of code.

Arduino Forum > Using Arduino > Project Guidance > Measuring capacitor discharge curve issue

arduino