Saturday, April 24, 2010

SONAR

I've had a few electronic designs published lately -- but actually (shhh), I've designed nothing new in a year. With one single exception, that is -- a SONAR (= SOund NAvigation Ranging). This appears in next month's Everyday Practical Electronics (EPE) magazine. What makes the design special is that it uses only a dozen common components. While its range is only one metre/yard, this is still tremendously useful. It will detect a door opening, a car/automobile approaching a wall, a suitcase being moved, and so on. OBSERVATION: I have a Super Simple Sonar on this blog, except that this will not switch anything. The EPE design will switch on the city lights if desired.

Wednesday, April 7, 2010

Groote Kerk


Here's another photo of the Groote Kerk (“Great Church”) of Cape Town -- taken with a compact Olympus camera -- its once proud tower, nearly five storeys high, now tucked away in an urban nook. The Church was founded in 1665 -- thirteen years after the first settlers arrived. It has the largest pipe organ in South Africa. You may click on the photo to enlarge to 70k.