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EPE PIC MAGNETOMETRY
LOGGER
Magnetometers are instruments for measuring the direction
and/or intensity of magnetic fields. Such fields are created by
electrical current flow and also exist naturally in
ferromagnetic substances, such as iron and nickel. It is the
latter fields that this magnetometer has been designed to
detect, particularly those associated with man’s activities.
This design is PIC-controlled and uses two FGM-3 fluxgate
sensors from Speake & Co who describe them as “very high
sensitivity magnetic field sensors operating in the ±50
microtesla range”, which covers the Earth’s magnetic field.
Their applications include conventional magnetometry,
ferrous metal detectors, magnetic material measurement and
archaeological artifact assessment.
Data is recorded by the PIC to on-board memory, from
where it can later be downloaded to a Windows-based PC
for visual analysis.
PORTABLE MINI ALARM
This is a unit that should find many applications within home
and business security. Battery-powered and about the size of
a small brick, it can be simply placed at the area to be
protected, switched on and left. Intruders entering the area will
trigger a siren that is loud enough to alert anyone nearby.
The circuit features “pulse counting” that enables it to
distinguish between passers-by and someone loitering,
perhaps with “intent”, in the protected area. The count can be
adjusted by the user for the desired degree of immunity from
false alarms. The battery life will depend upon the number of
detections and alarms, but the circuit is a micro-power design
and is capable of remaining “on guard” for periods well in
excess of a year.
FRONT PANEL FINISHING
Adding the finishing touches to your project can be a timeconsuming
and laborious task, and the results may not be as
professional as you would have liked! However, with the use of
a home PC, professional looking front panel overlays can be
quickly and easily produced. This article shows you how.
PLUS
BONGO BOX
The Bongo Box is for budding drummers everywhere
who like to tap out a rhythm with their fingertips on
any available surface. This project is guaranteed to
make such individuals even more annoying to any
partner, parent or pet in the vicinity!
In fact, the Bongo Box could be of serious use to
anyone involved in playing or recording music using
MIDI (Musical Instrument Digital Interface) controlled
instruments. Any box or enclosure can be turned into
an electronic drum by placing this design inside it
and linking it to a PC. The response of the device is
rapid, and drumming your fingers on the box causes
a series of drum sounds to be played in quick
succession.
This a great improvement over the usual situation
where a MIDI keyboard is used to trigger sounds –
normally it is not possible with a keyboard to mimic
the quick “rolls” that drummers play. The Bongo Box
makes this technique possible, without having to go
to the expense of buying an electronic drum kit!
TEACH-IN 2004 – PART 9 LOCK AND ALARM SYSTEMS
NO ONE DOES IT BETTER
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Demand is bound to be high
JULY 2004 ISSUE ON SALE THURSDAY, JUNE 10
Everyday Practical Electronics, June 2004 367