The intelligent temperature sensor DS18S20 from Dallas semiconductor is a calibrated precise two resp. three pin device that interfaces direchtly to microcontrollers or PCs producing Celsius readings. The so-called 1-wire protocoll (better `one DATA wire. ) can be adapted to the RS232 port with minimal component count. Simple circuits are publishe
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d that do not work too well with new DS18S20 components. But improvements are on the way. Latest desktop or laptop computers do not provide serial RS 232 interfaces any more, but instead numerous USB interfaces. USB is an intelligent interface, in every application it requires an intelligent IC to signal the type of interface to the computer when USB gets connected. On the other side more power, up to 2 W, is available to operate the 1-wire bus circuit. The FTDI USB-to-serial interface chip provides the electrical interface to the computer as well as the functions of a "fake" serial protocol. When properly applied with suitable hardware the computer may still believe to operate a serial interface when in fact USB is used. Below a prototype board of such an interface is shown that uses a USB-to-serial chip to provide the "Transmit TXD" and "Receive RCV" signals that finally operate a 1-wire- hardware interface. The circuit uses an ready-made kit interface adapter board for the FTDI USB-RS232 chip in surface mount technology. The 1-wire circuit interface includes a voltage doubler circuit to provide "always" enough drive voltage and current for the 1-wire bus even in case when the USB voltage is lower than normal. The zener diode at the output node limits the drive voltage as well as external overvoltage or cable noise. Compared to a passive pullup resistor this circuit provides substantial loop current even at voltages just...
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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