Measure Voltage, output through p0-p7

adi

I have problem with measuring voltage and showing the result per pin 0-7. the Voltage that i measured range from 0V until 2,5V.

pin 3 is always 5V, even when i give no input voltage.( ADCValue is about 125)
and when the ADCvalue is about 79, pin 1 is 5 V and also pin 3.

Anyone knows why?confused:

here is my program:

import stamp.core.*;

public class Distanz {

static int PORTA;

final static char CLS = '\u0010';
static int ADCValue;
static ADC voltMeasurer = new ADC(CPU.pin14, CPU.pin15);


public static void main() {

CPU.setOutput (CPU.pins[noparse][[/noparse]0] + CPU.pins+CPU.pins+CPU.pins+CPU.pins+CPU.pins+CPU.pins[noparse][[/noparse]6]+CPU.pins[noparse][[/noparse]7]);

while(true){
CPU.delay(5000);
ADCValue = voltMeasurer.value();
System.out.print(CLS);
System.out.println("ADC value is: ");
System.out.println(ADCValue);
if(ADCValue<=64)
{
CPU.writePin(CPU.pins,true);
CPU.writePin(CPU.pins,false);
}
else if((ADCValue>64) && (ADCValue<=128))
{
CPU.writePin(CPU.pins,true);
CPU.writePin(CPU.pins,false);
}
else
{
CPU.writePin(CPU.pins,false);
CPU.writePin(CPU.pins,false);
}

} // end while
} // end main
}

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Adi Prasojo
Student of Mechatronics
Koblenz-Germany

Peter Verkaik

First, you must use the bitwise OR in setOutput

CPU.setOutput (CPU.pin0 | CPU.pin1 | CPU.pin2 | CPU.pin3 | CPU.pin4 | CPU.pin5 | CPU.pin6 | CPU.pin7);

Secondly, you must specify which pins in the if/else construct

CPU.writePin(CPU.pin0,true);
CPU.writePin(CPU.pin1,false);



You can use pins[noparse][[/noparse]x] but then you must specify x. If the pin number is constant, using pinX
requires less code.

regards peter

adi

thanks peter, and sorry for the writing.

actually all i want to do is to measure a voltage from a sharp distance sensor GP2D120(output vary fom 0V until 2,5 V). and i would like to show the result in PORTA. do you or anyone know about this?

because I've tried to change the code just like you suggested. still I have the same problem(the output in Pin2 and 3 won't react according to the code).

to measure the voltage i use pin16 and pin15.

regards Adi

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Adi Prasojo
Student of Mechatronics
Koblenz-Germany

Peter Verkaik

Post your complete program as an attachement,
maybe something else is wrong with your code.

regards peter

adi

here is the code:

import stamp.core.*;

public class Distanz2 {

static int PORTA;

final static char CLS = '\u0010';
static int ADCValue;
static ADC voltMeasurer = new ADC(CPU.pin14, CPU.pin15);


public static void main() {

CPU.setOutput (CPU.pin0 | CPU.pin1 | CPU.pin2 | CPU.pin3 | CPU.pin4 | CPU.pin5 | CPU.pin6 | CPU.pin7);

while(true)
{
CPU.delay(5000);
ADCValue = voltMeasurer.value();
System.out.print(CLS);
System.out.println("ADC value is: ");
System.out.println(ADCValue);
CPU.writePort(PORTA,(byte)ADCValue);


} // end while
} // end main
}

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Adi Prasojo
Student of Mechatronics
Koblenz-Germany

adi

i've changed the code, already.

i've tried to make it a bit simple. but it doesn't work too. the output (from System.out.println(ADCValue)) vary from 70 to 125. I had never been able to get output 0 when the sensor output voltage 0V.

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Adi Prasojo
Student of Mechatronics
Koblenz-Germany

Post Edited (adi) : 1/24/2008 5:59:34 AM GMT

adi

inpVoltage(sensor)
v
|
|
res(22K)
|
+

---

<p15
|
+---res(22K)---->p14
|
__+
---1uF
|
|
|
GND

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Adi Prasojo
Student of Mechatronics
Koblenz-Germany

Peter Verkaik

The ADC definition:

· /**
·· * Create a sigma-delta analog to digital converter virtual peripheral and
·· * start it running.
·· *
·· * @param inPin the pin to be used as an input by the converter.
·· * @param outPin the pin to be used as an output by the converter.
·· */
· public ADC(int inPin, int outPin) {
··· this.inPin = inPin;
··· this.outPin = outPin;
··· start();
· }

You use in your code:
static ADC voltMeasurer = new ADC(CPU.pin14, CPU.pin15);
so pin14 is the input pin, pin15 is the output pin.
Your schematic shows them swapped.
So try this in your code:
static ADC voltMeasurer = new ADC(CPU.pin15, CPU.pin14);

regards peter

adi

I've found the problem measuring the voltage from this GP2D120 sensor.
it looks like his output must be pulled down. I've used 10 kohm resistor to pull it down.
maybe if I use bigger pulled down resistor, would be better.

The schematic is attached.

regards Adi

this is the code:

// Program Listing 4.3 - ADC Test

import stamp.core.*;

public class Distanz2 {

//static int PORTA;

final static char CLS = '\u0010';
static int ADCValue;
static ADC voltMeasurer = new ADC(CPU.pin9, CPU.pin8);


public static void main() {

CPU.setOutput (CPU.pin0 + CPU.pin1 + CPU.pin2 + CPU.pin3 + CPU.pin4 + CPU.pin5 + CPU.pin6 + CPU.pin7);

while(true)
{
CPU.delay(5000);
ADCValue = voltMeasurer.value();
System.out.print(CLS);
System.out.println("ADC value is: ");
System.out.println(ADCValue);
CPU.writePort(CPU.PORTA,(byte)ADCValue);


} // end while
} // end main
} // end class declaration

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Adi Prasojo
Student of Mechatronics
Koblenz-Germany