Connect to camera
Select the Up Looking Camera tab. Note, that the camera used does not automatically change, at this point the image comes from the down looking camera. Select one of the generic USB cameras, until image from the up looking camera appears. Align it roughly. The correct orientation is such that when you cover front part of the hole, the bottom part of the image gets covered (left side in the image is left side in real world).
Although the USB cameras have the same name, the program does recognize and remember which one is which. Go back to down looking camera tab, and press Select without changing the selected camera in the selection box. The image should change correctly to the down looking camera.
Align the Camera, Set the Image Size
Place a ruler at the camera so, that its edge aligns to the middle of the image. Go back to down looking camera tab and align the ruler with machine X axis just like you did when aligning the up looking camera. Re-check, that the ruler edge aligns with the cross on the up looking camera image, and adjust the alignment of the up-looking camera.
Once satisfied, measure the box size just like with up looking camera, and put the values to the boxes. For maximum accuracy, have an empty PCB under your ruler, so that the measurement is done at PCB surface height.
How to switch between cameras, troubleshooting
There are three methods for selecting between the cameras, in the preferred order. Select the Keep Active box and try a few times switching between the tabs and clicking select. If there are any issues, keep reading:
Keep Active: Tries to start two camera streams and keeps both active. Switching the active video stream is handled inside LitePlacer software. This consumes more USB bandwidth, but is the fastest method, if your system supports it.
Fast: Does activate/deactivate cameras, doing it efficiently (but see below). Activate this method by unselecting “Robust” checkbox.
Robust: Does activate/deactivate cameras, using a slower but supposedly, more robust method.
Some machines have had issues on selecting between the cameras. Things that have helped:
- Connecting cameras directly to a computer (not through a hub)
- Connecting cameras to different USB ports, so that they are using different USB controller chip inside the machine
- A tip from a customer: “Solved it; went into device manager, selected one of the cameras and clicked “Update driver” then selected to browse manually for a driver and continued to select from a list of devices, selected “Imaging devices” -> Microsoft -> USB Video camera.”
- Make sure the selected cameras point to different physical devices. This is a bit awkward as the cameras are identical (except for a cryptic individual string), so they have the same USB device name. The easy way to tell the camera devices is the order where they are on the list; makes sure you select the upper in the list for one camera and the lower for another. If you doubt this might be the issue, pay attention to the cryptic strings shown in the log window.
- The OpenPnP folks have encountered similar issues with USB and cameras than some LitePlacer users. Jason von Nieda, the guy behind OpenPnP, has written a good page about the issue: https://github.com/openpnp/openpnp/wiki/USB-Camera-Troubleshooting-FAQ.
- Also, this thread has good hints and a link to a tool that might help in diagnostics: