May 2013

Electronic Stethoscope

This sophisticated listening project lets you check engines or machinery for diagnostic or troubleshooting purposes, as well of course as being used to check a heartbeat.  It has switchable frequency-shaping in four bands, allowing you to home in on sounds which might otherwise be masked out.

You can listen in on a speaker or headphones, and it’s battery powered for portability. A mechanic’s adaptor for engines etc. and a simple ‘eavesdropping’ unit to monitor birds and animals from a distance are also described. An interesting audio project for everyone!

PIC/ AVR Programming Adaptor Board (Part 1)

Do you frequently program microcontrollers with a serial programmer? Want to streamline the process so you can do virtually any microcontroller? This Programming Adaptor Board, in combination with an in-circuit serial programmer (ICSP), allows you to conveniently program most DIP 8-bit and 16-bit PIC micros as well as 8-bit Atmel AVRs – more than 450 devices in all. ZIF socket, 3.3V or 5V selectable, fuse protection for micro, compatible with PICkit3 and AVRISP MkII.

Cheap, high-current Bench Supply

This article explains how an old computer PSU can be adapted to offer a bench power supply with 5V, 12V and possibly 3.3V outputs at high current output (typically 18A or more). A standard PSU is converted to a standalone bench-top unit with fan cooling and 4mm output terminals. Full details and photos are provided, including hazard warnings which must be observed at all times.

 WARNING! MAINS VOLTAGE IS PRESENT THROUGHOUT A TYPICAL COMPUTER POWER SUPPLY. This project is intended for experienced competent constructors only.

Jump Start (Part 13) – Signal Probe

The antepenultimate article in our series specially written for beginners, young students and hobbyists describes another simple but useful piece of test equipment in the form of a simple hand-held signal probe that can inject and trace signals in analogue and digital circuits. Circuit modelling in Circuit Wizard software is included in detail, along with PCB information.

Raspberry Pi Multimedia Hub

Make your Pi multimedia aware! Our in-house Pi chef dishes up  a main course of installing a multimedia hub on a Raspberry Pi, focussing on the XMBC application to provide music, photo, video and XMBC-compatible programs. In a forthcoming follow-up article an IR receiver and more add-ons will be described.

PIC n MIX

Our PIC micro expert moves on to explain how an LCD can be hooked to a low-power processor circuit, and in a follow-up will describe how a Real-Time Clock (RTC) can be used to reduce power consumption even further.

Also in this issue:

• Circuit Surgery describes first steps in using LTspice to analyse op-amp bandwidth.
• Max’s Cool Beans – Max is building a technical anachronism of a stage prop to demonstrate the perils of ionising and non-ionising radiation!
• Net Work – the Pure Avalon 300R PVR and improving wi-fi speeds on a legacy laptop.
• Ingenuity Unlimited  – more readers’ own circuit ideas.
• Techno Talk – on the advent of Li-Fi, an optical version of wi-fi.