Projects in the August 2006 issue of EPE Magazine

The No. 1 UK Magazine for electronics technology and computer projects
Loudspeaker Level Meter — this unit helps with home theatre sound setup and is great for Public Address systems too. This handy loudspeaker level meter has its own built-in microphone and a 10 l.e.d. bargraph to let you quickly set all channels to the same relative level. -13dB to +6dB display range. Level control. Attack and decay rates follow VU standard.
Adjustable DC-DC Converter for cars — now you can run many kinds of electronic equipment in your car with this portable converter. Run your laptop or charge a 12V sealed lead acid (SLA) battery for example. This improved design is based on an efficient switched-mode design capable of delivering from 13.8V up to 24V d.c., maximum current 2A @ 15.7V. Recommended continuous output 500mA @ 24V, 1A @ 16V. Fuse and reverse polarity protection. MOSFET power transistor output.
Telephone Dialler for Burglar Alarm Systems — now you can beef up your home's security system with this special unit. It dials a preprogrammed number when triggered, and sends a warning tone via a modem. No direct connection to the telephone line is needed by the circuit. It can monitor normally-open or normally-closed contacts or an external voltage. Dial in and test if system is operational. Programmed easily via PC/ RS232C connection. EEPROM stores settings in case of power outtage. PIC16F84 based.

High-Intensity Torch (Flashlight) — Build a brighter torch with variable intensity and flashlight options. This design uses a superbright white Luxeon Star/O LED along with an intelligent control design based on a PIC 12F629 8 pin microcontroller. Phew! The microcontroller constantly measures the 6V supply voltage and acts as a pulse width modulator to control the l.e.d. brilliance without needing a series resistor. Push switch control for light level. Compact size, construct it in the housing of your choice, or e.g. an old torch housing.

Also in this issue: Techno Talk on low frequency sound waves, and more trade mark origins. Did you know that MK Electric stands for... well, check our article this month! Interface: our PC interfacing column offers a visual approach to producing virtual controls. PIC n MIX - range checking, for moe advanced PICmicro users. Teach-In 2006 - our marathon educational series introduces PIC microcontrollers. Circuit Surgery - our helpdesk column discusses the problems of logic level conversion. All this and more in EPE Magazine - buy it now or subscribe online!