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Wireless PA
for Classrooms - In large classrooms, many a times the
teacher’s voice is not audible to students in the back rows. So the teacher have to literally shout to be heard
by every student. Presented here is a circuit that can act as a wireless speech-aid for teachers so that their
voice reaches every student even in a large classroom. . . . [© EFY Enterprises Pvt. Ltd. All rights reserved.]
Wireless Phono Oscillator - A "phono oscillator" is a simple, short-range AM band transmitter that was typically used to
send the signal from a phonograph to a nearby radio, eliminating the need for an Amplifier and speaker. This
version uses only one transistor and. . .
Wireless Radio Data Link - This is a description of a very simple unit designed and constructed for use as a wireless
data connection between two nearby computers. The error rate is excellent over short runs, and the transmission
speed means that a useful PPP link. . .
Wireless RF PWM Dual Motor Controller - This is a very simple Wireless RF transmitter circuit that consists of the Holtek HT-12E
encoder chip and AM 418MHZ-transmitter module(WZ-X01, other similar device can be used). Using the hybrid RF xmit/receive
modules make building the RF remote control a lot easy. . .
Wireless RFID
Smart Key Detector - Many cars now use a key with an
imbedded RFID microchip. The microchip is read when the key is inserted into the car’s ignition. The keys
containing a microchip often look the same as most other keys. People duplicating car keys will often not know of
the microchip. This circuit will light a LED if it detects a key containing a 125KHz RFID chip. . . . [Hobby
Circuit designed by David A. Johnson P.E., 07/09/06]
Wireless
Short-Range Devices: Designing a Global License-Free System for Frequencies < 1 GHz - Analog Devices-Analog Dialogue. . . [by Harney, Austin and O'Mahoney, Conor]
Wireless
Telephone Eavesdropper Electronic Circuit - The IR
transmitter connects to a telephone circuit, and transmits both sides of all telephone conversations to any
line-of-sight location, within 40 feet. No power is taken from the central office, as long as all phones remain
on-hook. The current flows through the phone and back to the central office. . .
Wireless Temperature & Humidity Sensor with
USB - this project is based on obdev's Remote Sensor
example and their firmware-only USB implementation; the main change is the replacement of the analog sensors with
a Sensirion SHT11 digital temperature and humidity sensor. . .
Wireless Temperature &
Humidity Sensor with USB Interface - This project is based
on obdev's Remote Sensor example and their firmware-only USB implementation; the main change is the replacement
of the analog sensors with a Sensirion SHT11 digital temperature and humidity sensor. . . .
Wireless Temperature Monitor Has Data-Logging Capabilities - 01/19/12 EDN Design Idea You can make a wireless temps system with two ICs. You can use
a local temperature sensor and an ASK (amplitude-shift-keying) transmitter/receiver pair to design a simple
wireless temperature-monitoring system with data-logging capabilities. A microcontroller processes and displays
the temperature reading to the user. The microcontroller’s onboard UART (universal asynchronous
receiver/transmitter) also allows for data-logging applications. . . [by Tom Au-Yeung and Wilson Tang, Maxim
Integrated Products, Sunnyvale, CA]
Wireless Weather Station. Part
1 - In the Midwest, the main topics of conversation may
include the local football team or how the crops are doing. Inevitably though, the conversation always leads to
the weather. Most of us take the weather for granted. . . [Jerry Wasinger- Circuit Designer]
Z1 Small 3-wheel ROBOT with Infrared eye - Z1 is a small three wheel robot that avoids obstacles which it senses with its active
infrared sensors. Each rear wheel has its own motor, the single front wheel is not powered. The robot steers
"like a tank" by rotating the rear wheels in opposite direction. . . [Copyright 2008 Ayman CDMA]
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