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Showing posts from May, 2009

Logitech Pan/Tilt Python C Extension

I just started learning C++ in earnest about a month ago. This weekend I felt like I knew enough to start looking at Python C extensions, so I wrote one to control the pan and tilt functions of my Logitech Orbit. I used this camera previously for my OLPC telepresence project.

There's already a similar module out there, called lpantilt, that does this using Cython. But, I wanted to take a crack at it myself and do it with straight C.#include <Python.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <fcntl.h>

#include "linux/videodev2.h"
#include "uvcvideo.h"

static int pantilt(int pan, int tilt, int reset) {
struct v4l2_ext_control xctrls[2];
struct v4l2_ext_controls ctrls;

if (reset) {
xctrls[0].id = V4L2_CID_PAN_RESET;
xctrls[0].value = 1;
xctrls[1].id = V4L2_CID_TILT_RESET;
xctrls[1].value = 1;
} else {
xctrls[0].id = V4L2_CID_PAN_RELATIVE;
xctrls[0].value = pan;
xctrls[1].id = V4L2_CID_TILT_RELATIVE;
xctrls[1].value = til…
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