25 January 2011

Want to drive a hearing loop using a conventional voltage (audio) amplifier? This Hearing Loop Signal Conditioner includes signal compression and has a treble boost control to compensate for high-frequency roll-off due to loop inductance. It uses low-cost parts and is easy to build.

21 January 2011

Last month, we described the main features of the USB Data Logger and gave the circuit details. This month, we give the assembly procedure, explain how to install the Windows driver and PC host software and describe how the unit is used.

20 January 2011

Interesting circuit ideas which we have checked but not built and tested. Contributions from readers are welcome and will be paid for at standard rates.

17 January 2011

If you've ever had to buy a high-current bench supply, you'll know they don't come cheap. But you may well have such a supply sitting unloved and (until now!) unwanted in the back of a cupboard. It's the power supply in that old computer you never quite got around to throwing away!

14 January 2011

Commercial cranial electrical stimulation (CES) units cost hundreds of dollars but this one is cheap and easy to build. It is battery-powered, portable and has adjustable current delivery and repetition rate.

08 January 2011

Digital storage 'scope technology has pushed ahead in leaps and bounds over the last few years. Each new model offers higher sampling rates, wider bandwidth, deeper sample memory plus a full colour display growing in both resolution and screen size - combined with shrinking physical size and a lower price tag than previous models. Here's a look at the DST1102B from Chinese firm Tekway, showing just how far DSOs have come to date. It offers an impressive array of features, for a price that simply blows away most of the competition.

06 January 2011

Here's a simple - and cheap - little 433MHz receiver that has many uses. It is ideal for checking that a suspect 433MHz "wireless" device (and there are scads of them) is actually working. It's great for finding out where interference is coming from. But most importantly (we believe!) it makes a great tracker for "fox hunts" and the like.

02 January 2011

Back in April last year, the Australian Government announced a landmark agreement that will eventually provide high quality digital TV services to viewers who cannot receive terrestrial digital TV (ie, digital TV services from transmission towers in their area).

22 December 2010

Last month, we described the circuit for the Hearing Loop Tester and gave the assembly details. This month, we show how to build a calibration coil and adjust the tester so that it gives accurate results. We also describe how the unit is used.

18 December 2010

In this month's final part, we explain how to use the DAB+/FM Stereo Tuner and describe the menu system. We also show you how you can upgrade the firmware if necessary and describe various features of the tuner in detail.