Turn laser on and off while receiving depth image

Technical Support & Q&A
1

Hi. I am trying to turn the laser on and off while receiving depth images. I checked the examples on how to disable the laser using xnUSBOpenDeviceByPath / xnUSBSendControl and this works. But AFAIK, I cant use those while the device is open and blocked? Is there a way to acces the USB Handle using the astra API or OpennNI?

EDIT
I also found this example: Multi-camera Control using OpenNI and the S/N

I managed to compile the project on linux. But it looks like xnUSBOpenDeviceByPath can’t open the already runnign device and the app crashes.

2

Looks like it works when using libusb directly

                libusb_device_handle *dev;

                libusb_context *ctx;
                libusb_init(&ctx);
                libusb_device **devs; //pointer to pointer of device, used to retrieve a list of devices
                ssize_t cnt = libusb_get_device_list (ctx, &devs); //get the list of devices

                int nr_mot(0);
                for (int i = 0; i < cnt; ++i)
                {
                    struct libusb_device_descriptor desc;
                    const int r = libusb_get_device_descriptor (devs[i], &desc);
                    if (r < 0)
                        continue;

                    printf("Device: %i Vendor: %i Product: %i\n", i, desc.idVendor, desc.idProduct);

                    // Search for the aux
                    if (desc.idVendor == 0x2bc5 && desc.idProduct == 0x0402)
                    {

                        if ((libusb_open (devs[i], &dev) != 0) || (dev == 0))
                        {
                            printf("Cannot open aux");
                        }
                        // Claim the aux
                        printf("Openning device aux %d on 0\n", i);
                        libusb_claim_interface (dev, 0);
                        break;

                    }
                }

                //libusb_free_device_list (devs, 1); // free the list, unref the devices in it

                {
                    uint8_t buf1[10];
                    *(uint16_t*)buf1 = 0;
                    int cmd_len = 2;

                    uint8_t obuf[0x400];
                    uint8_t ibuf[0x200];

                    cam_hdr *chdr = (cam_hdr*)obuf;
                    chdr->magic[0] = 0x47;
                    chdr->magic[1] = 0x4d;
                    chdr->cmd = 85;
                    chdr->tag = 1; //must be ++
                    chdr->len = cmd_len / 2;
                    memcpy(obuf + sizeof(*chdr), buf1, cmd_len);


                    std::cout << libusb_control_transfer(dev,  LIBUSB_REQUEST_TYPE_VENDOR, 0x00, 0x0000,0x0000, obuf, cmd_len + sizeof(*chdr), 5000) << std::endl;
                    unsigned int actual_len;
                    std::cout << libusb_control_transfer(dev,  LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_ENDPOINT_IN, 0x00, 0x0000, 0x0000, ibuf, 0x200, 5000) << std::endl;
                }
3

(I cannot reply on “Multi-camera Control using OpenNI and the S/N”, it is limited to 3 replies for new users…

Yes, they work individually and, when both connected, they have different URI’s.
The one that gives the error is always the second camera. If I connect 3 cameras, again, the second receives the error.

4

Is it possible to turn multiple sensor laser on and off using Orbbec’s SDK? Any document or sample code available?
Thanks in advance!