Projects in the May 2000 issue of EPE Magazine

PIR Checker: this gadget will test your outdoor PIR-controlled lamp, offering a 0-9 digital count of how many times it triggered during the night. Great for setting up and fault-finding.

Teach-In Part 7 - Op.amps
Onwards we go with our educational series which uses free interactive software with your PC, to demonstrate electronic principles. This month our tutor provides an in-depth look at operational amplifiers, describing many different configurations of this ubiqituous building block. Solderless breadboard experiments connect directly to the parallel port for on-screen demos and measurements.

Our Low-Cost Capacitance Meter is a simple starter project that lets you measure most capacitors in the range 1nF to 10µF. Switchable range, moving coil meter display. Stripboard construction, battery operated.

Versatile Mic/ Audio Preamp
Using the new Analog Devices SSM2166 chip, this easy to build but highly versatile project offers automatic gain control, compression, limiting and noise reduction. The SSM2166 is designed for processing microphone inputs to computers but finds itself at the heart of this adaptable constructional project.

In the February 2001 issue we suggested FML Electronics as a source of the pre-amp chip who had a few in stock, call 01677 425840.
16-Channel 2-Wire Transmission System
Our PIC-based 8 to 16 channel 2-wire on-off signalling system offers a multitude of applications in security monitoring, alarm systems, model railroad control and lots more besides! Separate add-on (see June 2000) allows for a complete voice communication system to be constructed. Free source codes available from our FTP site.

Technology Timelines (4)
Our intrepid time travellers describe the plethora of computing developments during the period 1900-1999, aided and abetted by many interesting photographs from the pioneering era of computer evolution. Immense in its detail, the article commences with mechanical computing machines and progresses onto valve (tube) powered monoliths, ending with today's modern personal computer. Don't miss our fascinating free wall poster too, listing all the key developments from 1500- 1999.

Also in this issue, New Technology Update talks about low voltage MPUs, Circuit Surgery wraps its mini-series on op.amp chips and Net Work (The Internet Page) examines the latest crop of free Internet offerings for UK users.