| Al bar is an ultrasonic movement detector, based on the Doppler effect. It uses only one ultra- sonic transducer as both transmitter an...
| Al bar is an ultrasonic movement detector, based on the Doppler effect. It uses only one ultra- sonic transducer as both transmitter an...
| Several readers have asked us to design a good metal detector. When our `research and development` group took a closer look at the prob...
| Relatively few components are used in this eggtimer. The `boiling time` is automatically determined according to the size of the egg an...
| The washing machine starts to leak while you`re watching TV .... Or the freezer fails and you don`t notice it for a day or two .. Or th...
| A circuit for producing a calendar display using the pulses from a digital clock has already been described in Elektor 8. This design p...
| A domestic intercom doesn`t require a complicated circuit. The unit described here uses only a handful of components, even though an...
| Although designed as a warning horn for use . with the `Albar` ultrasonic alarm system de- scribed elsewhere in this issue, the...
| The well-known TTL IC type 74 I 21 is a monostable multivibrator that can be set to give an output pulse with a duration...
| In this age of digital things (?) it is nice to dress up the front panel of home-brew equipment with digital readouts. This handsome...
| Summer is long gone, and all of nature is proceeding through its autumnal eventide towards winter hibernation. Birds are departing,...