High-speed photography at home

about the project

I am passionate about photography. And I also like to collect all kinds of electronic stuff. Probably because of this, I felt that I simply had to try to take a high-speed photograph. Edward Maybridge indulged in such a photo in the nineteenth century. In this post I will talk about the basics of high-speed photography and how I collected my photo trigger.

Introduction

Speed ​​photography is an extremely fast shutter speed, less than a millisecond. The principle of operation is simple: a sledgehammer, a camera, a flash, a trigger and an object are placed in the room. In absolute darkness, they open the shutter of the camera, start firing at the object with a sledgehammer, the trigger responds to noise and turns on the flash. A flash of a fraction of a millisecond illuminates the flying shards of the object. After that, the shutter of the camera is closed. On the sensor remains a snapshot of flying shards.

I want to talk about how to assemble such a thing at home.

Assembly

Formulation of the problem

I wanted the trigger to work with different sensors. I decided to start with an audio sensor and a laser beam. With audio, everything is clear: if a loud enough sound is noticed, then you need to turn on the flash. The laser sensor is almost like a film: the laser is aimed at a photosensitive element. If the beam crossed something, then you need to turn on the flash. I wanted to be able to adjust the sensitivity of the sensor and flash delay.
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Component selection

• ATmega 328P with Arduino on board, frequency 16Mhz. I like this chip because of its simplicity.
• Flash Vivitar 283 . Old, Japanese, dollars for 30. The biggest plus of this device is that, firstly, it is difficult, and, secondly, it is not a pity to break it. The disadvantage of the device is that the voltage on the contacts is 380 volts. It hurts to touch a finger.
• Gate TS1220 and opto-isolator MOC3010M . These two devices allowed the circuit to withstand voltages up to 600 volts.
• Sparkfun Microphone
• Laser pointer, bought in the nearest store and the photo resistor GL5528 .
• Any infrastructural trifle: toggle switches, potentiometers and a battery with a MAX1555 charger .

Here is what my desk looked like after the prototype assembly:


The method of laser irons will remain on the next project. While everything was soldered on a regular board with holes:

Code

The microcontroller program was very simple. The most interesting thing was to do the main loop as quickly as possible. For the first time in my life, code optimization was quite real: I missed a couple of milliseconds, and the most interesting event was missed.

Sources can be found on google code .

Housing assembly

I really wanted the project to have a decent body. I purchased some cheap boxes and took up drawing. First, I marked out what the user interface would look like:



After that, he took the drill:



After that, I took the dye for plastic VHT SP950 and painted the case. I really wanted to get rid of the kind of cheap plastic. Three days of drying and parts could be returned to the house:


The case is left for small. It was necessary to stick signatures to the controls. I discovered a great tool - decals. Print signatures on special paper, dip paper in water and translate directly onto plastic.


Here is the result:

Result

The first results were not very satisfactory. The trigger worked as it should, but the object turned out to be blurry. And for the laser sensor:



And for the audio sensor:



The matter turned out to be the power of the flash: an overly powerful flash quickly turned on, but rather slowly went out. Simple tuning reduced power and photos became clear.

Here is a flying drop of water:



But the coffee beans are landing in a cup:

Conclusion

I really enjoyed working with the AVR microcontroller, high-speed photography and “iron” user interfaces.

However, now I have no idea what to photograph. Suggestions (as well as questions and comments) are very, very, very welcome.