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Channel Data LoggerWith a specification too long to list, this design utilises the new PIC 16F877 microcontroller in response to readers' requests for a versatile design. It also forms part of a mini-tutorial, offering a practical example of how to apply Arizona Microchip's exciting new development. The PIC 16F877 has a greater programming memory than the "traditional" PIC 16F84 series, and is loaded with new features which makes this new microcontroller the answer to many constructor's dreams. Follow John Becker's two-part article and become acquainted with these new chips.
Ultrasonic
Puncture Finder
This unique design checks for ultrasonic emissions created by the escape
of air from a bicycle tyre puncture. It can even be used to check for
many slow punctures, and is much more convenient than using the traditional
methods of puncture detection. The design uses surface mount components
to provide an effective and compact unit, with audio signal output. Break
out that puncture kit and throw away that bowl of water!
Practical Oscillator Designs - Part 2
More worked examples and practical circuits for hands-on constructors
in the second part of this very detailed series. This month's article
discusses Colpitts oscillators and its variants.
Sound
Activated SwitchJust one logic gate allows a simple microphone to control - well, almost anything! It's amazing what you can do with a single 4069 inverter. The article also explains the technical differences between buffered and unbuffered CMOS logic gates. Various application suggestions are provided for experimentation including a relay interface, baby alarm and xenon flash trigger.
Freezer
AlarmAnother low-cost starter project - avoid an expensive thaw and insurance claim with this simple "high-temperature" alarm. Temperature probe monitors the freezer and sounds a buzzer if the temperature increases beyond a preset limit. Easily constructed on our multi-purpose p.c.b. We've "thawt" of everything!
Magnetic
Field DetectiveA neat and sensitive instrument for detecting low-level magnetic fields, this project can even detect moving magnets at five metres through brick walls! Using a special fluxgate magnetometer sensor, the design is ideal for experimenters wanting a simple method of indicating the relative strength of magnetic fields.
From
Pipelines to PylonsWhat does 'ground' mean? Why is electricity a sine wave? Whatis three phase? We offer a marathon tour of a modern power station and electricity distribution grid, with the help of the international power generation company National Power plc. This two-part article describes the process of electricity generation, commencing with a comprehensive low-down on a gas-fired power station (Killingholme "A" in Lincolnshire, UK), tracing the route all the way through to the safe delivery of an electricity supply to your home. A fascinating article for everyone, the article has much theory and background information, and answers many questions that may have nagged you in the past!