This section describes an experimental low power, low bandwidth data signaling system that operates at 100 MHz (In the FM broadcast band in the U.S.). Before operating a radio transmitter, find out what kind of transmitter operation, if any, is permitted in your locality. Radio transmitter operation is a serious legal matter. In the United States, operation of unlicensed intentional radiators is covered by Part 15 of Title 47 of the Code of Federal Regulations. This design can be readily adapted to different frequencies and different power levels. If you choose to build and operate the transmitter described here, you do so at your own risk. I'm only publishing this as an example of what can be done, and to show how easy it is to build a simple but functional receiver.
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This is an adapter that allows a terminal to communicate via a 100 MHz data channel with peripherals on the same desk top. Keystrokes from the terminal are are received through the RS-232 connection and sent through the 100 MHz RF data channel. See the page, Digital Wireless for the Desktop, on this site, for the basics of the transmitter, receiver, and data format. The reason I made this was to make a simple method of switching between instruments on my desktop. I was staring to accumulate a number of microcontroller-based devices that I want to be able to switch my computer among quickly and this provided the simplest desktop networking solution I could think of.
Any data received over the 100 MHz RF data channel addressed to the terminal is decoded and sent to the terminal. The transmit and receive address of the terminal is set by the user and stored in EEPROM. The address field has a range of 0..7, and the transmit and receive address can be changed by entering an escape sequence. The sequence{,T,3}, for example, sets the transmit address to 3. This flexibility allows the terminal to "connect" on any of multiple devices on the desktop by merely entering the appropriate escape sequence. It is planned that most devices will be test instruments and will speak only when spoken to (that is, in response to a request), and that they will all send data to the terminal. This simplifies things a lot because only 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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