August 2007 Issue
A summary of this month's contents.
TwinTen Stereo Amplifier
The ideal compact amplifier to accompany your MP3 player, games machine etc. This tiny stereo amplifier produces a surprising amount of power considering that it runs from a 16V a.c. 1.25A a.c plug pack.
This is an ideal project for beginners and students because the mains voltage supply is taken care of by a mains adaptor. Includes input selector switch, bass, treble, balance and volume controls. The circuit is built onto a larger-size PCB to help with construction. Output short circuit and thermal overload proof.
Specification - output (both channels into 4 or 8 ohms): 6W. One channel into 4 ohms : 10 watts. THD @ 1 Watt continuous into 8 ohms 0.04%. Frequency Response 10 - 72 kHz. S/N @ 10W into 4 ohms -80dB.
PIC Scope V2 (Part 1)
A PICmicro and PC controlled hobbyist oscilloscope — this update of the Virtual Scope (Jan 1998) is a much simplified version working under both PICmicro and PC control. It is intended for moderately simple signal tracking and display.
The PIC scope allows not only general audio analogue signals from two sources to be displayed on-screen simultaneously but also a waveform analysis of them. It can additionally display the logic waveforms generated by external 8-bit digital signals from a single channel.
(Oct 2007 page 26). PLEASE TAKE NOTE Page 15, Parts List. The type number for IC7 and IC9 should read LMC6482. The circuit diagram Fig. 2 is correct.
(November 2007 page 17). PARTS LIST - IC15 should be a 79L05 not 78L05 as listed. The circuit is correct.
It has come to light that the individual setup of PCs can prevent the V2 PC Scope from working with its serial control. This can be cured by installing the entire EPE Serial software from our PICs/ SerialOCX folder of our Downloads page. The OCX software has been tested with W98, 2000, ME and Windows XP.
(January 2008 EPE P. 41) In Fig. 6 the two leads marked NC (no connection) on the left should be marked CLK (upper) and DATA (lower). IC15 should be a79L05, the circuit digram is correct. In Fig. 6 there is a small section of PCB track missing - the right-hand side of C11 needs connecting to the 0V line (the left-hand side of C12).
Readers whose software is not storing new Baud Rate data, for reasons unknown, can change the Baud value to the one required in the V2scopeS
RFID Security Module
Introducing a contactless "key" system using Radio Frequency Identity technology. Perfect for use with door opening and security systems, the RFID security module uses one or more contactless RFID keys, each one being encoded with a unique identity. No batteries are needed in the tags. When a tag is brought within range (90-100mm) of the reader, it is energised by the reader's magnetic field. The key then transmits its unique code to the reader, which validates the code and arms or disarms the alarm system accordingly. The reader stores up to 24 tag ID codes. Use it as a standalone keyless entry system or part of a larger alarm system.
Printer Port Hardware Simulator
Now you can test parallel printers and other parallel peripherals without a PC with this low cost circuit. Our Printer Port Simulator allows you to manipulate the port's data and control lines, monitor the status lines and even send the printer (or other equipment) a 'strobe' pulse. Has 6 LEDs for status monitoring.
Source codes 0807.zip
PCB artwork pcb0807.zip
Please Take Note - PIC Scope V2
As from July 2013 issue PCB artwork is available free to subscribers only.
Non-subscribers may purchase artwork files for a nominal sum. Please contact our Orders Dept for information or to place an order.
EPE Printed Circuit Boards
We can supply ready-made printed circuit boards (8-digit order codes) to the original design specification via mail order or from our Online Shop.