Projects in the April 2000 issue of EPE Magazine

This fabulous PIC 16F876-based probe offers frequency and voltage readout, with an approximation of the waveform under test. Designed mainly for audio signal finding, very straightforward to build. Free source code available from our FTP site. Note: this design is not a microscope!

In the May 2000 issue (P.382) we advised that the part number for the orange case should be 281-6841 and not as shown.


Garage Link
Ever left the garage door open all night? Me too! Our project sends a brief radio signal every 45 seconds into the house, generating a warning tone to warn that the door is open. Uses 418MHz or 433MHz pre-built RF modules. Photocell assures night-time only operation. Switch-activated by garage door position.

Teach-In 2000 (Part 6) - Logic gates, Binary and Hex Logic
Essential educational info. for the novice using our free interactive PC software and practical experiments to establish the foundations of electronics. Our major tutorial series, not to be missed!

High Performance Regenerative Receiver (Part 2)
Constructional details are provided of our retro-look high quality receiver, covering 130kHz - 30MHz. The receiver has a clear, pleasant tone and output is more than adequate.

In June 2000's issue (P.468) we reported that some examples of the 2N3819 f.e.t. performed badly or not at all. The author advised that this could be cured by increasing R5 to 15k.
In Jan. 2001 issue (P.31), note that on P.301 April 2000 issue, the main receiver printed circuit board copper foil (Fig. 5) as shown: all the leadout pads for the dual-gate MOSFET (TR3) are connected together by the circular track just above the p.c.b. # number, which shorts out all TR3's pins and stops it operating. To remedy this, the thin copper circle should be cut away (e.g. with a blade), and the thicker tracks can be trimmed back to the first sodler pads if you wish.

Technology Timelines (3)
Communications and Related Technologies 1900- 1999

Our intrepid time travellers Clive "Max" Maxfield and Alvin Brown continue to outline many major technological breakthroughs of the past century, this time dusting down telephones and television sets, satellite development, the magnetron and the microwave. And the Internet too (hurray!)

Slave Flash
Ideal for beginners, this Starter Project enables a secondary flashgun to be triggered by the main flash, using an optical-sensitive phototransistor. Perfect when no sync. socket is available. Easily built using ordinary stripboard.

Also in this issue: Circuit Surgery continues with an inside-look at op.amps, Net Work - The Internet Page - looks at domain names, Ingenuity Unlimited offers more reader's ideas, and there's a bumper Readout page of readers letters.