Projects
Remote Control Using Telephone
Here is a teleremote circuit which enables switching on and off of appliances through telephone lines. It can be used to switch appliances from any distance, overcoming the limited range of infrared and radio remote controls.
The circuit described here can be used to switch up to nine appliances...
Line Follower Robot
Microcontrollor AT89C2051 and H-Bridge driver L293D were used to control direction and speed of motor.
Circuit diagram of Infrared sensors and comparators.
Position of sensors, left hand side is side view and right hand side is top view.
Software
Software for write to...
4 Channel RF Remote Control
*already test this circuit. It work well.
Figure 1. RF 4 channels remote Transmitter
This is a very simple RF transmitter circuit that consists of the Holtek HT-12E encoder chip and AM 418MHZ-transmitter module (WZ-X01). Using the hybrid RF xmit/receive modules make building the RF...
9V battery indicator
This is a very simple 9V low battery indicator circuit which has 2 LEDs, one green which will light up when the battery voltage is higher than 6.9 volts and one red LED which will light up when the battery voltage is bellow 6.9 volts. You can use BC547 … BC549...
Blown Fuse Indicator
Generally, when an equipment indicates no power, the cause may be just a blown fuse. Here is a circuit that shows the condition of fuse through LEDs. This compact circuit is very useful and reliable....
FM Telephone Bug
Here is a simple transmitter that when connected to a phone line, will transmit anything on that line (execpt the dial tone) to any FM radio. The frequency can be tuned from 88 to about 94Mhz and the range is about 200 feet. It is extremely easy to build and is therefore a good, useful beginner...
