This version of the trigger circuit for the stop-motion camera system uses an electret microphone for a sonic input, but the designer can substitute an LED and photodiode pair to create an optical trigger. For a recent home-brew project, I built a stop-motion camera system using a timed flash and shutter system. The system required a trigge
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r mechanism to set the timing in motion. The input trigger needed by the system controller is a pulse train of at least two pulses. After the system is armed, the first incoming pulse acts as a pre-trigger, and the second is the final trigger for the system. The circuit can use either an optical trigger (a light curtain ) or a sonic trigger. With very minor modifications, it can work with both triggers. The parts are all through-hole components, chosen for availability. The trigger circuit comprises five major components: the sensor, the conditioner, the pulse generator, the opto-isolator, and the power conditioner ( Fig. 1 ). The power conditioner, which is not discussed in this article, supplies both positive and negative 9 V to all the circuitry on the board, using an LM317 and an LM337, respectively. For several reasons, the trigger circuit uses an opto-isolated output. First, due to the sensitivities of the controller, I had to ensure that no ground loops were present. Previous tinkering had shown that they could cause random firing of the system controller. Second, the voltage levels ( ±9 V) used on this board aren`t compatible with the system controller circuitry (+5 V). Finally, the flash circuit (on another board) could potentially cause a large ground bounce (a 10- µs discharge of about 1200 V) that could damage circuitry elsewhere. Note that the opto-isolator base connection (pin 6) is left floating. The...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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