Author Topic: Inexpensive Acoustic Trigger  (Read 1852 times)

Jeff_Dawson

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Inexpensive Acoustic Trigger
« on: March 16, 2021, 12:44:37 PM »
I’ve found a way to acoustically trigger my Chronos 1.4 camera that is very inexpensive, accurate and easy to build.

The ‘sound detector’ board from SparkFun (SEN-14262 -- https://www.sparkfun.com/products/14262) is an analog audio sensing board that is able to output a TTL compatible pulse when it detects a sound.  This board is inexpensive ($12.50 CAD) and easy to hook up.  The board is easily powered by batteries (I use three AA batteries = 4.5 V).  If you connect the ‘gate’ output to your camera IO1 input then you can trigger your camera on a variety of acoustic events – claps, bangs, bird-tweets, stubbing your toe and cursing, etc.

The board also outputs an analog signal that is equivalent to the acoustic oscillogram and outputs an analog voltage that follows the envelope of the sound detected – so it’s quite a versatile board.  You can also change the microphone gain to make it more or less sensitive (it’s default is quite sensitive and worked well for me as delivered).

My plan is to incorporate this into a nice project case with BNC output so I can easily cable it to my camera in future.

I’ve attached a picture from my oscilloscope showing the output from the board.  You can find additional documentation about this board easily on-line.

I consider this a small work-around until the acoustic triggering features of the camera are implemented.

Please note that I do not work for SparkFun and I have not received compensation for this post in any way.  I’m just an absent minded professor-scientist.

Jeff.

« Last Edit: March 16, 2021, 12:50:39 PM by Jeff_Dawson »