IR Sensor-tracker.zip

[alexrobotics]

We have a question regarding the IR Sensing system using tracker.zip. We are experiencing no servo motion to find the IR Beacon. Our current set-up is as follows:

Left joystick is in port 1, right joystick in port 2.

Our left servo is in PWM 1, right servo in PWM 2.

Left motor is in PWM 3 through a Victor 884 Speed Controller, right motor is in PWM 4 through a Victor 884 Speed Controller.

Our IR Sensors for left to right go as follows: Left most sensor is in Digital I/O 3, the other left sensor is in Digital In/Out 4, the right sensor is in Digital In/Out 5, and the right most sensor is in Digital In/Out 6.

We have read about the robot doing a spin to find the beacon, and our robot seems to move but the servos show no motion. We’ve also read about a beacon type selector switch. Is this something we make???? Little to nothing is known about this switch. We saw it referred to in the tracker.c file.

[Dave Flowerday]

Do you have the 7.2v backup battery connected to the robot controller? The servos won't operate without it.

[Mark McLeod]

Originally Posted by alexrobotics

We have a question regarding the IR Sensing system using tracker.zip. We are experiencing no servo motion to find the IR Beacon. Our current set-up is as follows:

Our left servo is in PWM 1, right servo in PWM 2.

Our IR Sensors for left to right go as follows: Left most sensor is in Digital I/O 3, the other left sensor is in Digital In/Out 4, the right sensor is in Digital In/Out 5, and the right most sensor is in Digital In/Out 6.

We have read about the robot doing a spin to find the beacon, and our robot seems to move but the servos show no motion. We’ve also read about a beacon type selector switch. Is this something we make???? Little to nothing is known about this switch. We saw it referred to in the tracker.c file.

If you are using tracker.zip "as is" then your robot will not move at all. It has no driving commands incorporated. It only moves the servos to search for the beacon. The "navigate" code demonstrates how you can move your robot.

Dave's note on the 7.2v battery sounds like the most likely explanation of your problem. The servos (on PWM01 & 02) should "search" even if the IR sensors aren't connected at all.

The beacon switch is something you'll need to have eventually, like the left/right field switch. It might be easier to think of it and implement it as a Blue/Red alliance switch. (There is a way to automate this, but I wouldn't suggest you try it.) For now you can hardcode it to the type-0 beacon on the EDU controller PWM1 output. In tracker.h you'll find the line:

#define DESIRED_BEACON_TYPE rc_dig_in07 // this assumes that rc_dig_in07 is a digital input

For testing just change it to:

#define DESIRED_BEACON_TYPE 0 // hardcode beacon to type-0 (PWM1 on EDU)

[alexrobotics]

Originally Posted by Dave Flowerday

Do you have the 7.2v backup battery connected to the robot controller? The servos won't operate without it.

Well no we didn't we were using that battery to power the edubot to make the wavelengths for our big robot. We will try it. Thank you.

[dmellich]

We were able to get the system working great - IR sensors tracking the beacon.

Now the question is, how do we get the tracker code integrated with the default code so that all systems (drive, pneumatics, other motors) can operate simultaneously with IR? Are there certain files from tracker code (*.c, *.h) that need to be placed into the FRCcode to allow them to be compiled and linked?

Thanks for everyones help, couldn't have done it without you.

[Mark McLeod]

Originally Posted by dmellich

Now the question is, how do we get the tracker code integrated with the default code so that all systems (drive, pneumatics, other motors) can operate simultaneously with IR? Are there certain files from tracker code (*.c, *.h) that need to be placed into the FRCcode to allow them to be compiled and linked?

Add these to your MPLAB project.
tracker.c
tracker.h

Use the routines in the tracker s/w as a guide to changes in the rest of the code.
Add in user_routines.c:

#include "receiver.h"
#include "tracker.h"

in User_Initialization()

Initialize_Receiver(); /* not required as it's also called by Initialize_Tracker() */
Initialize_Tracker();

In user_routines_fast.c add the whole "// external interrupts 3 through 6" interrupt section for the IR sensor interrupts.

	else if (INTCONbits.RBIF) // external interrupts 3 through 6
	{
		Port_B = PORTB; // remove the "mismatch condition" by reading port b            
		INTCONbits.RBIF = 0; // clear the interrupt flag
		Port_B_Delta = Port_B ^ Old_Port_B; // determine which bits have changed
		Old_Port_B = Port_B; // save a copy of port b for next time around
	 
		if(Port_B_Delta & 0x10) // did external interrupt 3 change state? - IR sensor 1
		{
			Int_3_Handler(Port_B & 0x10 ? 1 : 0); // call the interrupt 3 handler (in receiver.c)
		}

		if(Port_B_Delta & 0x20) // did external interrupt 4 change state? - IR sensor 2
		{
			Int_4_Handler(Port_B & 0x20 ? 1 : 0); // call the interrupt 4 handler (in receiver.c)
		}

		if(Port_B_Delta & 0x40) // did external interrupt 5 change state? - IR sensor 3
		{
			Int_5_Handler(Port_B & 0x40 ? 1 : 0); // call the interrupt 5 handler (in receiver.c)
		}
		
		if(Port_B_Delta & 0x80) // did external interrupt 6 change state? - IR sensor 4
		{
			Int_6_Handler(Port_B & 0x80 ? 1 : 0); // call the interrupt 6 handler (in receiver.c)

		}
	}

And add the tracker servo processing in Process_Data_From_Local_IO()

	static unsigned int Old_Clock = 0;

	if (Clock > Old_Clock) // stay synchronized to beacon data updates (this is important)
	{
		Track_Beacon(LEFT); // allow the left beacon tracker state machine to run
		Track_Beacon(RIGHT); // allow the right beacon tracker state machine to run
		
		if ((Tracker_Data[left].Status == BOTH_IN_VIEW) &&
			(Tracker_Data[right].Status == BOTH_IN_VIEW))
		{
			// both trackers have an angular solution; calculate beacon vector
			// here using the known baseline distance between the trackers and
			// angles derived from the two Tracker_Data[].Position variables

			// calculate new drive motor PWM values here

		}
	// finally, update the servo motor positions
	LEFT_TRACKER_SERVO = Tracker_Data[left].Position;
	RIGHT_TRACKER_SERVO = Tracker_Data[right].Position;
	
	Old_Clock = Clock; // take a snapshot of the clock
	}

[Kevin Watson]

Originally Posted by Mark McLeod

Add these to your MPLAB project.
tracker.c
tracker.h

Don't forget receiver.c & receiver.h. BTW, if you're going through the trouble of adding the tracking functionality to your existing code, you might as well use the newer code found in tracker.zip.

-Kevin

[Mark McLeod]

Originally Posted by Kevin Watson

Don't forget receiver.c & receiver.h.
-Kevin

There's always somethin' I forget.
I guess it's hard to #include files you forgot to add in.

Thanks Kevin!