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Two new articles posted: Using a 10-turn pot with a delay unit

and Selecting a flash unit for high-speed photography


Crossed-Beam Photogate PCB Kit, unassembled



The crossed-beam photogate uses a pair of infrared photogates oriented at right angles to each other. This type of photogate can be used to automatically actuate a camera shutter when an object passes through the beam intersection. This makes it useful for photographing birds and insects. If a camera is centered and focused at the beam crossing, the shutter will be actuated only when the object moves through the point of focus. Click here for more information.


Crossed-beam Photogate

Completed assembly

While triggering a camera is the most common application for the crossed-beam photogate, the circuit can also trigger flash units and wireless transmitters and can be connected to the external input of a Multi-Trigger in order to use the delay timer.

The control box has the following features:

  • On-off switch
  • Internal 9V battery power (battery not provided)
  • Jack for optional AC/DC adapter
  • Smoothly-variable coarse and fine sensitivity controls
  • Jacks for the photogate and output cables
  • LED to indicate when unit is triggered
  • Focus switch for the camera

The CBP2-E kit includes the parts for all control box, wires, and cables. See the parts list here and assembly instructions here.


CBP2-E Crossed-beam photogate PCB kit, unassembled- $38.50


The CBP2-F kit includes the parts for a 10-inch square frame for the sensors. See the parts list here and assembly instructions here. (We sell the frame kit separate from the PCB kit in case you want to build a frame of a different size. We have successfully tested frames up to 12" square.)


CBP2-F Frame kit, unassembled- $14.95 each


A shutter cable is required in order to use the Crossed-beam Photogate to actuate a camera shutter. In order to trigger a wireless transmitter, see the 3.5mm male-to-male cable.

Camera shutter cables

Select the shutter cable for your camera below. See the list of compatible cameras here.

Canon 80N3 cable with adapter Nikon MC30 cable with adapter Nikon MCDC2 cable with adapter
Canon 80N3 Nikon MC30 Nikon MCDC2
Canon 60E3 cable 3.5mm male-female extension cable 3.5mm connectors
Canon 60E3 3.5mm male-female extension Cable connectors (DIY)
  • The Canon 80N3 and the Nikon cables are about 1-foot long and may be coiled or straight, depending on what we can get from our suppliers. The stereo plug is 2.5mm, and a 2.5mm to 3.5mm stereo adapter is included for connection to a trigger box. A 6-foot extension cable may be purchased for just $1.95 more.
  • The Canon 60E3 cable is 6 feet long with 2.5mm and 3.5mm plugs.
  • DIY option: If you want to use a shutter release cable that you already own rather than buying one of ours, you can just get the 3.5mm male and female stereo connectors and follow these instructions.

Shutter cable option



AC/DC adapter

9-V AC/DC adapter100-240 VAC to 9VDC Adapter

This AC/DC wall adapter provides a substitute for a 9V battery to power many of your circuits. The adapter accepts 100-240V input voltage at 50-60 Hz; output is a regulated 9 VDC. The power rating is 10 W. The AC plug is a standard 2-pin non-polarized US plug. An adapter may be needed for some countries.


$14.95 - 100-240 VAC to 9 VDC adapter - A9V

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