Tilt/Pan servo position with Arduino

md3530 · November 19, 2019, 9:44pm

I’m running the Pixy2 on an Arduino Uno using your ccc_pantilt.ino example. Seems to be working fine right out of the box which is great. I need to print the position of the pane & tilt servos.

Looks like this function is where the magic happens:
pixy.setServos(panLoop.m_command, tiltLoop.m_command);

I’ve been rooting around in the Pixy2.h and PIDLoop.h files to try and find if there is a variable that holds these values with no luck.

Any help would be greatly appreciated

edge · November 20, 2019, 3:36am

Hello,
The PID loop code is in this file:

github.com

charmedlabs/pixy2/blob/master/src/host/arduino/libraries/Pixy2/PIDLoop.h

//
// begin license header
//
// This file is part of Pixy CMUcam5 or "Pixy" for short
//
// All Pixy source code is provided under the terms of the
// GNU General Public License v2 (http://www.gnu.org/licenses/gpl-2.0.html).
// Those wishing to use Pixy source code, software and/or
// technologies under different licensing terms should contact us at
// [email protected]. Such licensing terms are available for
// all portions of the Pixy codebase presented here.
//
// end license header
//

#include <TPixy2.h>

#define PID_MAX_INTEGRAL         2000
#define ZUMO_BASE_DEADBAND       20

This file has been truncated. show original

The variable is stored in m_command, which is (in the case of the servos), the servo position.

Hope this helps!

Edward

md3530 · November 24, 2019, 7:17am

Thanks! I’ll try to summarize what I did.

I ended up creating a global integer variable “xyz” in the ccc_pantilt.ino example.

I then declared it as an “extern int” variable in the PIDLoop.h file. (I had to edit the .h file in notepad)
I then set xyz = m_command; at the right spot inside the PIDLoop.h file.

I then did a Serial.print(xyz); twice inside the ccc_pantilt.ino example. Once after panLoop.update(panOffset); and once after liltLoop.update(tiltOffset);

At the locations of these new print commands, I could redefine other variables such as PanPosition=xyz;, and TiltPosition=xyz; to store for other purposes to complicated to get into now.

If I didn’t need to store the values, I could have just done a Serial.println(m_command); inside the PIDLoop.h file at the right spot.