build an interface board to connect some scientific equipment (for me, a pair of photovoltaic tubes) to a personal computer to acquire measurements results. Signal properties were following: two channels with a common ground, 1 second of acquisition time, max 10V signal level. Desired digitizing properties were about 1000 samples per acquisition, 10 bit depth. The most attractive
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and cheap solution is to use a PC sound card as an ADC converter. However, most of laptop computers have only mono low-level microphone input onboard. After a careful research, a Texas Instruments PCM2900 chip [1] was chosen as a proper converter (fig. 1). It has a stereo I/O (only input is used in this project), USB interface and MS Windows drivers already shipped with an OS. A reference board design from TI was used (fig. 2). One can easily found it in the data sheet [2]. Output circuits were removed, and proper capacitors selected. C9 and C10 capacitors were removed as input signal have zero frequency (DC). Instead, a couple of potentiometers (5K and 10K) were placed to do fine board tuning. After an assembly has been finished, the board was plugged onto my PC (Windows XP): Check the "USB HID", "USB Audio device" and "USB Composite device". Also I had to specify a new source for sound recording.
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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