Super Ear Audio Telescope - Listen more clearly to those distant sounds using this parabolic microphone and audio amplifier. Useful in e.g. wildlife studies and eavesdropping (where legitimate). Comparable in performance to a commercially produced design, our DIY version uses an electret insert and an adaptable parabolic reflector to focus sounds from afar. Headphone output.

PIC Ultrasonic Radar - Now you can beef up your robot with EPE's new Ultrasonic Radar system. This experimental design uses a stepper-motor driven swept motion ultrasonic transducer to 'listen' to the landscape, to help your 'bot navigate or maybe take evasive action. Our free source code and software is available from our Download Area. Includes added value PC interface software that runs under Windows. For experienced constructors with PICmicro / design expertise.

Radio-Control Model Switcher - a radio-control power switch for models and other devices. Uses a spare RC transceiver channel to implement on-off power switching. Power MOSFET output. 24V 1A maximum or may be boosted via a relay.

Digital Lock - Continuing our Back to Logic Basics, this is a very neat digital lock that operates a relay when the correct sequence of buttons is pressed. The circuit can be configured in a number of ways.

Digital Scarecrow animal repeller - a simple ultrasonic generator that will help deter cats, dogs, foxes and more. Swept frequency sound generator. Full bridge MOSFET circuit drives a piezo horn in short bursts that are inaudible to humans. Long term battery operation.
PLEASE TAKE NOTE (July 2005 p 497) Page 431/432 Fig 3.1 and 3.2. The drain (d) and source (s) notations of TR2 and TR4 should be reversed. The orientation of the transistors on the p.c.b. should be rotated accordingly.