Coolmaster — turn a fridge into a wine cooler or a freezer into a fridge! You can convert a spare fridge into a wine cooler to hold your favourite tipples at just the right temperature (+9-15°C for a fridge or +4-10°C for a freezer). This op.amp based circuit used a solid state temperature sensor and opto isolator with a triac to add a reliable thermostatic action to a working fridge or freezer, at a threshold to please the discerning wine lover. Simply unplug again to restore normal fridge-freezer action.

WARNING - MAINS VOLTAGE ONBOARD. SUITABLE FOR ASSEMBLY BY COMPETENT AND EXPERIENCED CONSTRUCTORS ONLY.

Galactic Voice Effects Unit — an electronic voice changer that transforms speech from a mere human's into the robotic-like dialect uttered by motley Daleks, robots and similar extraterrestrial entities. Useful for communicating with aliens, every household should keep one in reserve for the time when aliens finally invade our corner of the Milky Way. Helps prevent misunderstandings and possibly negotiate your way out of intergalactic war. (Theory unproven by EPE ;-)

Our Galactic Voice project uses an MC1496 mixer to modulate human speech and play it over a loudspeaker. Built-in electret microphone and audio amplifier, with variable effect controls. Fantastic fun and completely self-contained, with all assembly details provided in full colour.

PIC MIDI Wave Sound Generator — this wavetable synthesis music generation source has a MIDI input and provides 18 wavetable instruments on a preprogrammed flash memory. Includes pianos, guitars, banjo, trumpets and more. Eight-note polyphony spanning five octaves (C2 to C7). Audio line and headphone output.

Straightforward PCB based assembly. Powered by a mains adaptor. This projects uses a PIC micro 16F628A, an 18F452 and a flash EEPROM type AM29F040. Source codes for all three devices are available free from our Downloads page. Preprogrammed chips are also available to buy online from the designer Rainbow Electronics.

Download a free sample (MP3) from Rapidshare here

Universal High-Energy LED Lighting System (Part 2) — construction details of our high power LED lighting unit featured last month and application notes to build an LED Powered spotlight for e.g. cycle use.

Also in this issue of Everyday Practical Electronics magazine:

Techno Talk discusses the impact of counterfeit components on the electronics industry. Practically Speaking - capacitor values and markings. Teach In 2008 Part 9: Watchdog Timer, Sleep and Interrupts. Circuit Surgery on the MAX8596X LED driver i.c. PIC n MIX Microcontroller I/O port expansion. Net Work - the impact that streaming TV programmes is having on Internet usage. EPE is available from newsagents or Subscribe Now.