'Quickstep'
stepper motor driver - this simple and versatile stepper motor driver
and controller is ideal for testing or using four phase unipolar types
of stepper. Uses a PIC 16F628, with source code available free from our
download area. A four-key push button pad allows
for single or continuous step, forward or reverse. The output drivers
are 2 amp discrete transistors that will cope with many types of new or
surplus steppers. Battery power-saving feature.
Crafty
Cooling - make a drinks can cooler,
and learn about the Peltier and Seebeck effects at the same time! This
article explains the theory behind solid-state electronic coolers (of
the sort used in e.g. battery-operated in-car drinks coolers), and you
have a chance to build your own experimental fan-assisted chiller using
the principles explained. You can also adapt the techniques for use in
your own projects.
Midi
Synchronome - Now you can improve your musical timekeeping when recording
MIDI instruments, using this novel audio-visual electronic aid. The MIDI
Synchronome will automatically synchronise to the clock messages output
by most MIDI instruments or computer sequencers. Furthermore, it also simulates
the swinging arm of a traditional metronome with nine l.e.d.s. The circuit
is based on a PIC 16F627, with free source code available from our
download area. Simple stripboard design. 
Body Detector
Mk. 2 - Create your own invisible defence shield with this updated
version of the original Body Detector. Not much bigger than a matchbox,
the circuit uses a super-sensitive detector and amplifier to respond to
the capacitance of the human body. It is extremely sensitive and can be
used to protect objects in burglar-alarm mode or in a number of other
adaptations.
For example, the detector wire can be hooked to a metal doorknob, or even an outdoor item such as a motorcycle, and extra options for ground/ earth wires can boost the circuit's sensitivity even more. The circuit has a multitude of uses limited only by your imagination (and desire to experiment!).
Teach-In
2004, Part 8 - our flagship educational series is specially written
for those new to electronics or who wish to brush up on their knowledge.
In this month's issue, the subject of movement detection is discussed
along with 'missing pulse' detection techniques. A variety of astable
oscillators are shown, including some interesting examples of 555 application
that can be built easily on solderless breadboard.
Interface
- the column for computer enthusiasts. This month we have more practical
ideas for the case-modding enthusiast. How to add an electroluminescent
(EL) panel, and several control circuits for flashing, dimming or sound-to-light
modulating EL drivers, to give your PC a bit more life!
ALSO
IN THE JUNE 2004 ISSUE: Clinical electrotherapy developments through
the ages, and a look at future trends, including deep-brain stimulation
using the Kinetra implantable pulse generator. Circuit Surgery:
power op.amps, servo controllers and more. Ingenuity Unlimited
- more readers' own circuits. Techno Talk on time-limited self
destructing electronics. PIC n MIX our new series for 'PICinners'
gives you a potted history of the EPE Toolkit and an overview of other
low-cost PIC programmers. ALL THIS AND MORE IN THE NUMBER ONE HOBBY
AND EDUCATIONAL ELECTRONICS MAGAZINE -
SUBSCRIBE NOW!