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Solar cell + Arduino + Audio triggered strobe + laser + long exposure

Things

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Set up so that when the beam between the laser and solar cell is interrupted, the strobe fires, which allows the camera to capture an image.



It works extremely well!
 

Gryphon

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Neat, but what exactly will you use it for? Capturing objects falling through the beam?
 

drlava

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set the beam just above table height and drop an egg!
 

Morgan

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I really like that! Good work! +rep. It may be time for me to start smashing light bulbs again!

A mate has got a spare mBed microcontroller. Any chance of posting some schematics? I'm a keen photographer and that is a piece of kit that has a place in my camera bag.

I'm assuming this would work with IR too?

Great stuff...

M
:)
 

lasersbee

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I'm pretty sure this could be done without even requiring a micro controller..

Just a Laser beam sensor (any fast photo sensor) with a sensitivity adjustment
and an output driver to trigger the type of camera you are using....

Nice project "Things".... yet another response to those who ask what Laser
are good for...;)


Jerry
 

Morgan

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Yeah, I suppose that's true. May be easier to intergrate to the camera remote through a controller though. From the sounds of it, the camera is already exposing and the strobe is being triggered as a flash. I can see my Canon being more than just a 1/0 trigger signal! More research on that needed I think...

I'd still like to see the setup and any diagrams/schematics. Looks like a fairly short delay between beam being broken and strobe going off.

Any other pics Things?

M
:)
 

Things

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I'll explain how it works:

The solar cell is connected up to an analog input, which returns a value between 0 and 1023, which is 0-5V. The strobe is connected to a regular digital output. Set up the solar panel, with the laser shining on to one of the sensitive part of the solar panel. Turn the light off, and have the room completely dark, and open the serial monitor and take note of the value it's receiving from the solar panel. Then block the beam, and note what value you get. Then all you do is use a if statement to trigger the strobe if the input value falls below a certain value. This is my sample code, you can use it on an Arduino straight up, or any uC with the Arduino bootloader.

Code:
/*
Camera Strobe Trigger. Triggers a strobe light when an analog input is above or below a certain level.
 
 */

int strobePin =  7;    // Strobe 
int val = 0; // To store the analog data
// The setup() method runs once, when the sketch starts

void setup()   {                
  // initialize the digital pin as an output:
  pinMode(strobePin, OUTPUT); // Sets the strobe pin to output
  Serial.begin(9600);  // Begins a serial connection
  analogReference(DEFAULT); // Not really needed, but can help if you have a smaller solar cell etc
}

// the loop() method runs over and over again,
// as long as the Arduino has power

void loop()                     
{
  val = analogRead(0); // Reads the voltage of the solar cell
  Serial.println(val); // Prints it to serial
  if (val < 100){ // If the analog value is less than 100...
  digitalWrite(ledPin, HIGH);   // Trigger the strobe
  delay(1);                  // Only hold the pin high for 1 millisecond, the strobe would have already triggered.
  digitalWrite(ledPin, LOW);    // Turn the strobe pin off
  }
}
 

Morgan

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That's a bit more technical. I haven't done any programming at all but was looking, (with this mate of mine), at the Arduino boards for a college project. He decided to go with the mBed because I think it had ethernet?

I get the way the system works if not the code writing. I know it's not as easy but do you have any plans to hook this up and directly trigger the camera and its flash? I think there would be a bigger delay whilst it travels round the internals of the camera but a cool way to go.

Off topic: Saw your tornado machine too. They look cool in fire! Have you built one of those?

M
:)
 

Things

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My camera is only a cheap point and shoot camera I got for $140, the only way I can do remote triggering on it is using firmware called "CHDK", which uses the USB port as a remote, but it takes around 3 seconds from receiving the signal, to the camera actually triggering :(

About the tornado machine, I have briefly tried with fire (Not in that machine though), by simply putting a garden torch top on a bench, then placing a plastic tube ontop of it with slits in the side to let in air, to start the rotation. It did work, until the tube melted :D

As for making it simpler, sure you could, but using a microcontroller gives you many more options. For example, you could set up a delay so when it gets triggered, it waits 5ms or something, then fires the strobe.
 

drlava

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You are correct the strobe could be triggered from a comparator without the processor. The processor is basically operating as a complicated comparator in this case. Delays could be done with R-C lowpass filters, too but hey as long as it's working that's better than just talk :)

Most cameras would be too slow to use the shutter trigger, the strobe trigger is much faster and probably more reliably timed.

let's see some breakage!
 

Hemlock_Mike

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For high speed photography, the typical method is to open the shutter and trigger the strobe. Camera commands are too slow.

HMike
 




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