camera Trigger

Description: A camera trigger designed to capture transient phenomena was created using a Mamiya ZE 35mm camera and a Mamiyalite ZE flash unit. At that time, the only method for remotely triggering the camera was through the cable release socket integrated into the shutter release button. This socket was intended for use with a mechanical cable, allowing the user to operate the shutter from a distance without introducing vibrations at the moment of capture. The solution for electrically releasing the shutter involved the construction of a solenoid trigger. The coil of a small solenoid was rewound to generate the necessary force when operated at 9V. This solenoid was of the retraction type, meaning that applying current to it pulled the armature inward. To modify it into an extension solenoid, a hole was drilled in the rear, and the camera end of a cable release was removed and soldered to the rear of the solenoid. A hole was drilled into the armature, and the pusher end of the cable release was soldered to the armature and fed through the solenoid, extending out the end of the cable release. The assembly was lightweight enough to be attached directly to the camera's shutter release without depressing the button. The solenoid's other end was threaded for mounting as originally designed, and a cap was found that fit this thread. This cap was particularly useful for automatic exposure settings, as the camera required partial depression of the shutter release for calculation. By adjusting the cap's position, the shutter release could be initially depressed sufficiently to activate the camera. To control the solenoid, a circuit was created to briefly apply current when triggered, with a test position that operated a sounder instead of the solenoid for setup purposes. This system was primarily used for photographing rocket launches. The trigger was compatible with hardwired circuits and an ultrasonic remote, constructed with surplus 40 kHz transducers. An extension cord with an inline switch allowed devices connected to the mini jack to operate as normally-closed or normally-open triggers.

The camera trigger circuit operates on a principle that allows for precise control over the shutter release mechanism, essential for capturing fast-moving subjects. The solenoid serves as the actuator, converting electrical energy into mechanical motion. The rewound solenoid coil is designed to achieve optimal force at a specified voltage, ensuring reliable operation. The transition from a retraction to an extension solenoid was achieved through mechanical modifications, allowing for the necessary actuation without compromising the integrity of the original components.

The control circuit includes a transistor switch that is activated by a triggering mechanism, which can be a manual button or an external signal from an ultrasonic remote. The inclusion of a test position is a valuable feature, enabling the user to verify the system's functionality without engaging the camera shutter. This is particularly useful during setup, ensuring that adjustments can be made without the risk of misfiring.

The ultrasonic remote adds versatility to the system, allowing for wireless operation. The use of surplus 40 kHz transducers facilitates the transmission of signals, providing a reliable method for triggering the solenoid from a distance. The extension cord with an inline switch enhances the flexibility of the system, enabling the user to configure the trigger operation according to specific needs, whether requiring normally-closed or normally-open functionality.

Overall, this camera trigger system exemplifies a creative integration of mechanical and electronic components to achieve precise control for photography applications, particularly in scenarios involving transient phenomena such as rocket launches.A camera trigger to capture transient phenomena. I had a Mamiya ZE 35mm camera and Mamiyalite ZE flash unit. Typical for bodies of its time, the only means of remotely triggering the camera was the cable release socket built into its shutter release button. This was meant to be used with a purely mechanical cable; it let you operate the shutter release from a small distance

away, and in a manner that avoided introducing vibration to the camera at the moment a picture was taken. My solution for releasing the shutter electrically was to make a solenoid trigger. I rewound the coil of a small solenoid so that it would produce the necessary force when operated at 9V.

It was a retraction type solenoid, meaning that applying current to it pulled the armature in. I wanted an extension solenoid, so I drilled a hole in the rear of it. I removed the camera end from a cable release - the part that screws into the cable release hole - and soldered it to the rear. I drilled a hole in the end of the armature, cut the pusher end off of the cable that was part of the release, soldered that into the armature, and then fed the pusher down through the solenoid and out the end of the cable release.

The whole thing was light enough that I could simply screw it onto the shutter release of the camera and it would be supported without depressing the button. The other end of the solenoid was threaded for mounting in the way it was originally designed for. I found a cap that would fit this thread. This turned out to be particularly useful, because if set for automatic exposure, the camera required that the shutter release be partially depressed for long enough for it to do its calculation.

If the shutter release was simply slammed down as fast as the solenoid did it, the shutter was released instantly and with incorrect exposure. By adjusting how far I screwed the cap down I could make the shutter release be initially depressed far enough to activate the camera.

To operate the solenoid I made a circuit that would briefly apply current to it when triggered. It also had a test  position that would operate a sounder instead of the solenoid, to facilitate setup. I ended up using this system mainly for taking pictures of rockets lifting off. The devices that I used with the trigger included hardwired circuits and an ultrasonic remote. The ultrasonic remote is at left. I made it with a pair of surplus 40 kHz transducers. The green extension cord at right has an inline switch to set whether devices plugged into the mini jack on the end operate as normally-closed or normally-open triggers.

The device with the bolt was used to take the tennis-ball cannon pictures below. No, I don`t yet have any of the other (more successful) pictures I took with this system scanned!