Lego wire guided robot in PBP

Hi

I build the following wire guidance sensor succesfully

http://www.philohome.com/sensors/fil...uide-schem.gif

I removed the D4,D5,D6 part and put a pullup to +5V on the collector of Q1

This is giving me a fine DC voltage according to the position of the wire to the 2 coils

So far so good

Can anyone help me to convert the following LEGO NQC code to PBP ?

I use HPWM 1 for the left motor, HPWM 2 for the right motor on a 16F877
ADCin 0 has the wire guidance sensor as input (which is the wire sensor)
Portd.0 is the fwd/rev Hbridge control for motor 1 (Left)
Portd.1 is the fwd/rev Hbridge control for motor 2 (Right)
Here is the NQC code


#define Wireguide SENSOR_1
#define Left OUT_A
#define Right OUT_C
#define Threshold1 10
#define Threshold2 25
#define HysterVal 8

task main ()
{
int Offset;
int Hyster=0;
int Diff;

// The wire guidance sensor is used
// the same way as a Light sensor
SetSensor (Wireguide, SENSOR_LIGHT);

// Reads the "no-signal" response. The sensor must
// be centered on the wire, or generator be off
Offset = Wireguide;
Wait(200);

// Starts driving

OnFwd (Left+Right);
while (true)
{
// Reads error signal
Diff = Wireguide - Offset - Hyster;
if (Diff >= -Threshold1 && Diff <= Threshold1)
// We are centered - drive straight
{
OnFwd (Left+Right);
Hyster = 0;
}
else
{
if (Diff > 0)
{
if(Diff > Threshold2)
// Very off center: turn in place
{
OnRev (Left);
OnFwd (Right);
}
else
{
// Slightly off center: shallow turn
Off (Left);
OnFwd (Right);
}
// sets hysteresis to avoid over-turning
Hyster = HysterVal;
}
else
{
if(Diff < -Threshold2)
{
OnRev (Right);
OnFwd (Left);
}
else
{
Off (Right);
OnFwd (Left);
}
Hyster = -HysterVal;
}
}
}
}

This page might be of help to someone:

http://www.philohome.com/sensors/filoguide.htm

Robert

Hi Robert, yess this is the side where the sensor and lego code is comming from

Quote:

---

ADCin 0 has the wire guidance sensor as input (which is the wire sensor)

---

There are 2 sensor signals on the schematic, but the code only checks one ADC signal?

Does defining it as a sensor light do something special?

Why not just ignore that code, use a PBP ADC sample program and use 2 channels (left and right sensor). Check the level of the signals and react accordingly?

Robert