A densitometer is one of the most valuable tools a darkroom enthusiast can employ. Up until recently, however, densitometers were expensive and bulky. Furthermore, densitometers which would talk to your computer and calculate effective film speed, contrast index or gamma were beyond the reach of almost all amateurs. Easily programmed microprocesso
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rs and the availability of highly accurate, inexpensive photodiodes make it possible for the photographer to build a densitometer which is reliable, accurate and inexpensive. The unit described here uses a new RGB photo-sensor, actually a 64 photodiode matrix with an incorporated light to frequency converter, the Texas Advanced Optical TCS-230 to greatly simplify the task. We chose to use the Basic Stamp II from Parallax Inc. as the microcontroller for this project since the device is relatively easy to program (it can be programmed right on the densitometer circuit board without having to be removed). If you ever get bored with the densitometer application for the Basic Stamp II you can always press it into service in another device. An outline of the Computing Densitometer is shown below: The outline above shows the several control lines from the Basic Stamp II to the TCS230 photo-receptor. The TCS230 integrated circuit has five input lines: two for color measurement, two to control the TCS230 electronic iris, and an Output Enable line (/OE). There is one data line and, of course, power and ground lines. The design presented in this article uses the Basic Stamp II to talk to your computer via its serial port, placing the data directly into a Microsoft Excel spreadsheet. Parallax makes available free to users of the Basic Stamp an Excel Macro which accepts the data into your PC from. The macro, StampDAQ can be downloaded...
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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