gentWIRE-USB allows camera control via the USB port  via a Radio Control (RC) system. From one (or two) channel on the RC receiver you have complete control over shutter and in the case of gentWIRE-USB2 many other camera features. 9grams (1/3oz) including ~250mm (~10")  3-pin standard servo cable and USB camera connector.

Ricoh & Nikon

gentWIRE-USB allows shutter release by simply plugging into the camera USB port. Operation can be triggered via a RC system or by shorting the blue wire to black. The unit will also waken the camera from "sleep"- useful for power saving in remote applications. Find compatible cameras from the table at the bottom of this page.

More Information: Operating Manual (Ricoh), Operating Manual (Nikon).

Canon

To operate with Canon cameras the camera must have a minor enhancement called SDM or CHDK added to the camera via the SD card, which enables operation of this device as well as many other creative possibilities for remote photographers. There are more details on this here.

gentWIRE-USB is the basic model allowing control of one camera function  - normally the shutter - from one RC receiver channel. This can normally be done without running a script in the camera.

gentWIRE-USB2 is an advanced solution using 2 RC receiver channels, and allowing 6 different commands to be sent to the camera which can be programmed via the CHDK Scripts to control many functions (e,g, Shutter, zoom, EV, focus etc). 

More Information: Operating Manual (USB), Operating Manual (USB2), Guide to SDM.

wired USB camera shutter control via RC:

Please note that gentWIRE-USB is designed to be used with a 
Radio Control system (such as those used with remote controlled planes),
For time-lapse or intervalometer use please consider
SDM Scripting or genTIMER.