A Passive Ethernet Hub
I tested this concept on a little network consisting of three PCs running under Windows 2000. It works well. The network adapters are normal Intel and 3Com models, set to 10 Mbps and Half Duplex. The computers are labelled A, B, C, and the UTP cables from the computers to the hub are 10, 16 and 35 meters long, respectively. More >
5 Zone Alarm System
This is a complete alarm system with 5 independent zones suitable for a small office or home environment. It uses just 3 CMOS IC’s and features a timed entry / exit zone, 4 immediate zones and a panic button. There are indicators for each zone a “system armed” indicator More >
sound operated switch with a relay driver
This sensitive sound operated switch can be used with a dynamic microphone insert as above, or be used with an electret (ECM) microphone. If an ECM is used then R1 (shown dotted) will need to be included. A suitable value would be between 2.2k and 10kohms. More >
over/under-voltage cut-off with on-time delay
Here is an inexpensive auto cutoff circuit, which is fabricated using transistors and other discrete components. It can be used to protect loads such as refrigerator, TV, and VCR from undesirable over and under line voltages, as well as surges caused due to sudden failure/resumption of mains power supply. This circuit can be used directly as a standalone circuit between the mains supply and the load, or it may be inserted between an existing automatic/manual stabiliser and the load. More >
speed control Temperature DC fan
Here is a simple circuit based on two transistors that can be used to control the speed of a 12 V DC fan depending on the temperature.A thermistor (R1) is used to sense the temperature. More >
VHF field strength meter
Telephone Hold Project for 2 phones in parallel
This Hold Phone Circuit will enable you to hang up one phone without losing the connection and move to another room or hall and pick up a different phone which is connected in parallel and continue your conversation. This feature is useful especially when you are staying in a house with different levels and having 2 telephones connected in parallel. More >
Ethernet Controller
This circuit is an ETHERNET controller I use the PIC18F452 and the mikroC C Compiler. I use also the JAVA SCRIPT information you can get from www.w3school.com I Control 8 outputs throw the WEB and transfer time information also. More >
USB sound card
Designing and building a USB sound card is no longer a head ache because we have got the PCM 2702 integrated circuit from Texas Instruments. The PCM2702 is an integrated 16 bit digital to analog converter that has two digital to analog output channels. The integrated interface controller of PCM2702 is compliant to the USB 1.0 standards. More >