Plugging the microscope in shows the following:
jon@leon:~$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 005 Device 002: ID 0813:0001 Mattel, Inc. Intel Play QX3 Microscope
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 003: ID 046d:c063 Logitech, Inc. DELL Laser Mouse
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
jon@leon:~$ dmesg
[...]
[101645.604019] usb 5-1: new full-speed USB device number 2 using uhci_hcd
[101645.811040] usb 5-1: New USB device found, idVendor=0813, idProduct=0001
[101645.811045] usb 5-1: New USB device strings: Mfr=2, Product=1, SerialNumber=0
[101645.811048] usb 5-1: Product: Intel Play QX3 Microscope
[101645.811050] usb 5-1: Manufacturer: Mattel Inc.
[101645.830281] Linux video capture interface: v2.00
[101645.833059] gspca_main: v2.14.0 registered
[101645.835930] gspca_main: cpia1-2.14.0 probing 0813:0001
[101646.140126] input: cpia1 as /devices/pci0000:00/0000:00:1d.3/usb5/5-1/input/input11
[101646.140262] usbcore: registered new interface driver cpia1
To talk to the camera driver module use v4l2-ctl to list and change the various settings it has available.
jon@leon:~$ v4l2-ctl -l
User Controls
brightness (int) : min=0 max=100 step=1 default=50 value=50 flags=slider
contrast (int) : min=0 max=96 step=8 default=48 value=48 flags=slider
saturation (int) : min=0 max=100 step=1 default=50 value=50 flags=slider
power_line_frequency (menu) : min=0 max=2 default=1 value=1
illuminator_1 (bool) : default=0 value=0
illuminator_2 (bool) : default=0 value=1
compression_target (menu) : min=0 max=1 default=0 value=0
Flipping the lights on/off involves setting the illuminator_n controls with bool values. illuminator_1 is the lower, transmissive, light source. illuminator_2 is the upper, reflective, light source.
It is easy to turn them on/off at will from a command line.
v4l2-ctl -c illuminator_1=0
v4l2-ctl -c illuminator_2=1
v4l2-ctl -c illuminator_2=0
v4l2-ctl -c illuminator_2=1