January 2009 Issue

A summary of this month's contents.

Radar Speed Gun (Part 2)

A microwave Doppler speed radar detector displaying in mph or kmh with 1% accuracy. Hold reading feature displays on 3-digit LED display, up to 250 kmh at a range of 200 metres. This month we provide full constructional details of the antenna assembly and p.c.b. construction. This design should be used responsibly and must not be used on the public highway.


20W Class-A Amplifier Module (Part 4)

Presenting a low-noise stereo preamplifier and remote volume control module for our high quality Class-A amplifier of October and November 2008. It has very low noise and distortion, with motorised potentiometer and muting, and can also be used with other stereo amplifiers. PIC 16F88 based, free source code available.


1000:1 UHF Prescaler

Our high speed prescaler can extend the range of virtually frequency counter to over 2.8GHz. It divides frequencies by exactly 1,000, so gigahertz (GHz) can be read directly on megahertz (MHz) displays. Includes surface mounted chips that require delicate soldering skills.


Breadboarding Projects (Part 4)

Our beginner's guide to electronics continues with two more solderless projects that can easily be experimented with. Two more simple solderless projects for beginners to practice with. Project 7 is a Clap Switch, an audio activated relay for controlling low voltage projects. Project 8 is a low-budget push to talk/ listen master-slave intercom that uses two small speakers as speaker/ microphones.


Also in the January 2009 issue:


  • Recycle-It - how to adapt an old digital stopwatch to form an interruptible count-up timer showing elapsed time. Whynot add a scrap thermostat to display how long a temperature is above or below a setpoint?
  • FlowCode and the Microchip PICKit 2 - how to use Flowcode to programme PIC microcontrollers with PICKit2
  • Techno Talk - a fascinating feature describing an application of carbon nanotubes to produce one of the most revolutionary and adaptable new materials ever created.
  • Practically Speaking - our column specially written to lend you a hand in the workshop. This month, some practical hints and guidance on handling transistors and diodes.
  • PIC n MIX - our resident PIC expert Mike Hibbett continues the mini series on interfacing PICs to the Internet via Ethernet.
  • Net Work - our On-line Editor's column gives readers a quick walk-through on the new EPE Online upgraded web site.
  • Circuit Surgery - our in-house 'surgeon' Ian Bell answers a reader's question on the problem of slew rate limiting with an in-depth explanation of the mathematics behind low pass filters.


Source code 0109.zip

PCB files pcb0109.zip

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