P COMP Midterm

This is the start of an ongoing project to design my own small film camera. The first step was to create a shutter mechanism. The first prototype consists of a simple single leaf shutter design acting as a window over a pinhole. I also added a shutter dial with a potentiometer that controls the amount of time the shutter stays open, otherwise it stays in the closed state. As I attempt to allow for even quicker shutter speeds, I will design a multiple leaf shutter. I also added a rugged momentary push-button switch as the shutter button.

To actuate the shutter, a push/pull solenoid is moving a piece of black cinefoil over the pinhole. This is currently not “light-tight” as these design elements will be implemented down the line.

The potentiometer is getting readings between .5-5volts, that I have mapped to a reasonable shutter range (2ms-250ms). This is equivalent to normal shutter values of (1/500-1/4). This is being read by the “intValue” and delaying how long the shutter stays open before closing itself. Another thing I will be improving upon is getting the shutter to know it’s been pressed to delay the actuation of a new one; this will stop the arduino from getting backed up and allow for film advancement in the future. An issue I ran into while designing this prototype is also a latency between shutter button and the solenoid, this is accounted for in the lack of current running from the 5V pin from the arduino. Hooked up to a power supply with more current, these shutter presses will not have that same latency. I will however need to complete my two blade design in order to get quicker shutter speed values.

I will also be implementing PWM for my solenoid so that once the pull operation starts, we can turn usage down to around 25% to lower the power consumption of the whole circuit. I look forward to improving upon this design and adding more elements for my final project.

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