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Assembly and Operating Instructions for Kits


Operation of the Sound Trigger 2 (ST2)


Assembly instructions for other kits


Control side Sensor side




Connecting a flash trigger cable

In order to connect your flash unit to the sound trigger output, you'll need a cable that connects to your flash unit on one end and to the RCA jack on the other. Photo 1 below shows one such cable that connects to the PC jack on the flash unit. Kits for these cables are available in the online store.


Powering the unit and checking operation

Insert a fresh 9-V battery into the battery holder and turn on the switch. The red LED should light. See Photo 2. Set the box on its side so that the piezo disc is exposed on the back. With your flash unit connected to the RCA jack and turned on, a snap of your fingers near the microphone should discharge the flash unit.


The open-shutter technique

High-speed photos taken with the help of the trigger typically use the open-shutter technique. For this method, photos are taken in a dark room with the shutter of the camera held open. When the flash unit discharges in response to the reception of sound by the trigger microphone, the image is recorded in the camera. The shutter is then closed before room lights are turned on.


Adjusting delays by distance

Hold the microphone near the event that you want to photograph, for example, a balloon burst. The distance between the source of sound and the microphone will determine the time delay before the flash discharges. Figure about a foot for each millisecond of delay. Aim the flash unit at the subject. When the sound is produced, the flash will discharge. Note that the trigger is designed to respond to loud, sharp sounds like claps, bursts, and explosions.


Adjusting delays electronically

As described above, synchronizing delays are produced by adjusting the distance between the microphone and the sound-producing event. If you prefer to adjust delays electronically or have an application that requires this, the output of the Sound Trigger 2 can be connected to the input of a Delay Timer as shown in Photo 3.


Caution: The Sound Trigger 2 isn't designed to trigger a camera directly. While connecting your camera shutter to the RCA jack isn't likely to damage your camera and may, in fact, trigger some camera makes, we don't recommend it. The output isn't optically-isolated from the circuitry of the sound trigger. If you want to trigger a camera, connect to a Delay Timer as shown in Photo 3 and then connect the camera to the Shutter jack on the Delay Timer.

Photo 1 Photo 2 Photo 3




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