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help me design an audio based camera controller circuit
mehmehmeh
Registered User regular
Registered User regular
short version:
So I want to build a controller box with a audio headphone input and a camera output. The controller would function as follows: when sound is heard on the right audio channel of the headphone input it will close the focus circuit to the camera. When sound is heard on the left channel it will close the shutter circuit. A constant tone in the left input channel would hold the shutter output circuit closed.
long version:
So I want to build a controller box with a audio headphone input and a camera output. The controller would function as follows: when sound is heard on the right audio channel of the headphone input it will close the focus circuit to the camera. When sound is heard on the left channel it will close the shutter circuit. A constant tone in the left input channel would hold the shutter output circuit closed.
long version:
I've been looking into building a dslr intervalometer and a hdr bulb bracket controller for a dslr camera.
I looked at the arduino and ti msp430 launchpad platforms but I worry about my programing and circuit design/building skills. There is also the very nice open camera controller project that uses a Nintendo DS to control the camera, but the cable interface looks complex to build and a second hand pre assembled cable is going for £85 on the forum.
I think I came up with an idea that should be a simple and cheap circuit to build, and would not require any programing.
I was looking at some of the microphone flash triggers (1, 2) for high speed photography and thought the circuit could be adapted for interval timing or bracketing. (also note I can't fully understand schematic diagrams (I don't know all the symbols), but I get a rough idea how it works from the descriptions)
So I want to build a controller box with a audio headphone input and a camera output. The controller would function as follows: when sound is heard on the right audio channel of the headphone input it will close the focus circuit to the camera. When sound is heard on the left channel it will close the shutter circuit. A constant tone in the left input channel would hold the shutter output circuit closed.
This way you could hook the controller to say a mp3 player with a audio track that would take a picture every 2 seconds (a short tone on the left audio channel every 2 seconds) or a bracketing sequence in bulb mode (1/4 sec , 1/2 sec , 1 sec, 2 sec, 4 sec exposure sequence would be heard as a 1/4 sec tone, Silent Interval (SI), 1/2 sec tone, SI, 1 sec tone, SI, 2 sec, SI, 4 sec)
You could have many different audio tracks stored on a mp3 player for different interval times or brackets. A playlist with a bracket audio track and a short silent track on repeat would result in a interval timed bracketing sequence.
I want to use optocouplers/optoislators to keep the camera electronics separate from the controller electronics. Also want to have led indicator lights for the two output circuits for debugging/testing.
canon camera remote pinout is as follows
1 - ground
2 - focus
3 - shutter
shorting pin 2 to 1 focuses the camera, shorting pin 3 to 1 will take a picture. Use of different cables would allow the controller to interface with multiple makes/models of cameras.
I looked at the arduino and ti msp430 launchpad platforms but I worry about my programing and circuit design/building skills. There is also the very nice open camera controller project that uses a Nintendo DS to control the camera, but the cable interface looks complex to build and a second hand pre assembled cable is going for £85 on the forum.
I think I came up with an idea that should be a simple and cheap circuit to build, and would not require any programing.
I was looking at some of the microphone flash triggers (1, 2) for high speed photography and thought the circuit could be adapted for interval timing or bracketing. (also note I can't fully understand schematic diagrams (I don't know all the symbols), but I get a rough idea how it works from the descriptions)
So I want to build a controller box with a audio headphone input and a camera output. The controller would function as follows: when sound is heard on the right audio channel of the headphone input it will close the focus circuit to the camera. When sound is heard on the left channel it will close the shutter circuit. A constant tone in the left input channel would hold the shutter output circuit closed.
This way you could hook the controller to say a mp3 player with a audio track that would take a picture every 2 seconds (a short tone on the left audio channel every 2 seconds) or a bracketing sequence in bulb mode (1/4 sec , 1/2 sec , 1 sec, 2 sec, 4 sec exposure sequence would be heard as a 1/4 sec tone, Silent Interval (SI), 1/2 sec tone, SI, 1 sec tone, SI, 2 sec, SI, 4 sec)
You could have many different audio tracks stored on a mp3 player for different interval times or brackets. A playlist with a bracket audio track and a short silent track on repeat would result in a interval timed bracketing sequence.
I want to use optocouplers/optoislators to keep the camera electronics separate from the controller electronics. Also want to have led indicator lights for the two output circuits for debugging/testing.
canon camera remote pinout is as follows
1 - ground
2 - focus
3 - shutter
shorting pin 2 to 1 focuses the camera, shorting pin 3 to 1 will take a picture. Use of different cables would allow the controller to interface with multiple makes/models of cameras.
mehmehmeh on
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Here's an example of a tone detector circuit. Pretty sure there are other ways to do it, too. You could actually use more than one of those circuits on a single line of audio to trigger multiple events (one triggered on, say, 10KHz and another on 15KHz).
That circuit even has an LED built-in. ;-)
Also, the minimum cycle time on that is (from a quick skim of the datasheet, may want to verify) going to be your detected frequency over twenty...so if you're using a 10KHz tone, that's 500Hz or a minimum pulse of 2ms. I don't know if that's an issue for your application.
reading on some different sound sensitive light circuits, opamp and MOSFETs should work? I saw one that just used a transistor on a headphone jack to work when set to music. (youtube link with annoying music)
A tone detector would produce a nice reliable digital output based on the presence of the selected input tone (which is entirely arbitrary), and you can then generate your sequences using something like Audacity. It's not particularly expensive, either...the whole setup in the circuit linked would probably run you...maybe six bucks? Depends on the caps, some can be pricey (buck or more).
You wouldn't even need to use pots for setting the tone, you could always tune the tone to a fixed resistor (install with a fixed resistor, then find the center frequency it's sensitive to using trial and error).
I'll let you decide what to use, obviously. This just seems to me like the best route to go with for what you're looking to do (assuming I understand what that is). We actually use a somewhat similar setup where I work, for transmitting low-bitrate digital data acoustically. We use multiple tones (which can be sent and detected simultaneously), with each tone representing a significant bit.
just to reiterate the basic goals:
controller with 3.5mm stereo audio input jack.
Loud noise on left channel input -> turn on led1
Loud noise on right channel input-> turn on led2
left and right channels should be independent of each other
when a sound activates one of the leds, the led should stay on and be constant for the duration of the sound
i'm going for as simple and as cheap as possible, so a 1 or 2 component circuit per audio channel solution looked good to me, be if you don't think it will work well I should probably go with the schematic you outlined since I don't have any experience in this area. I was wary of anything that needed to be tuned
Looking over that schematic you've got an LM567 (about $1.70 from Digikey for a DIP module), four capacitors (maybe $.50 apiece), and two resistors ($.10 apiece, or maybe add a buck or two if you go for a pot to tune it). Total of $4-$6 per channel, which ain't bad. Plus whatever you mount the circuit in/on, and a power supply.
Plus whatever you're using to couple it to the camera...yeah, sometimes this crap adds up. :P