August 2008 Issue
A summary of this month's contents.
Four Channel A/V Selector — select one of four S-video or composite video sources plus audio, with our electronic selector unit. Four S-video and 4 RCA composite video inputs, four stereo input channels.
Output 1 x S Video / RCA video, stereo RCA audio. Single PCB design, mains plug-pack powered.
Temperature Switch — a cheap general purpose adjustable design that can operate up to 245 degrees C. Double pole changeover relay output. Selectable heater/ cooler rising or falling temperature switching operation. Adjustable hysteresis controls the sensitivity (on-off switching differential). 12V operating voltage.
Mains Monitor — enables you to monitor a.c. mains power outlet usage around the home or other premises, allocating ID code numbers for individual sources. Suitable for 120V or 230V, 50Hz or 60Hz.
It monitors current consumed (up to 15A), transmitting data via a radio link to a central receiver connected to a PC via an RS232 port. The PC displays and stores the data for future reference or cost analysis.
Sadly the Mains Monitor was the last constructional project to be designed by our Technical Editor John Becker before he passed away. Characteristically, John's project was fully worked out from start to finish with valuable free Windows software and generous levels of technical support included, and his eager enthusiasm for the PIC Microcontroller would have a profound influence on the hobby electronics scene for ever more. A tribute was paid in the September 09 issue of EPE Magazine. ARW
DC Relay Switch — an automotive-style relay with opto-isolated input amplifier. Allows a current of just a few milliamps to control up to 30A. 12V or 24V operation. Normally-open and normally-closed output. A super-sensitive interface for heavy duty switching.
Also in this issue: Ingenuity Unlimited - readers' own circuits; Teach-In 2008 - Using PIC Microcontrollers (contd.) Techno Talk on Personal Area Networks. Interface - accessing serial ports using Visual Basic. Circuit Surgery describes some aspects of transistor saturation. PIC n MIX - more on I/O port expansion. Net Work - the Internet column - looking at the Asus Eee PC and Linux.
Source codes 0808.zip inc. PIC n MIX.
PCB artwork pcb0808.zip
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EPE Printed Circuit Boards
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