Low cost intercooler water spray controller — a sophisticated controller for turbocharged cars, this simple electronic circuit operates a water "mister" or sprayer that sprays a cooling mist onto the intercooler matrix. This lowers the intercooler's temperature and improves performance, especially on hotter days of the year.

 

Based on our Smart Mixture Display (Sept. 2006) circuit, only a handful of extra components are needed to produce this temperature -sensitive switch that has an LED bargraph showing intercooler temperature. A water spray pump can be adapted either from a windscreen washer pump and garden irrigation nozzle, or a solenoid pump used in domestic coffee makers.

 

Midi Drum Kit (Part 3): Building the sensors and stand — describing how to make both piezo-based and optically-based transducers for our Midi drum kit. You can use piezo-pad types for percussion-style input, or an optical sensor can be tapped by hand (e.g. bongo style) or for foot-activated devices.

Our article describes with full diagrams and photographs how to make a set of bongo drums, a foot controller and building a playing stand. Final part is in March 2008 which covers the software and how to drive it.

 

Studio Series - Stereo Preamplifier

This easy to build hifi preamp features high performance audio op.amps for ultra low noise and distortion. Its modular design incorporates five switched RCA phono sockets and support for a headphone amplifier. Full specifications, design considerations and constructional details are included in the two-part article.

• Freq Response flat from 10Hz - 20kHz, -1dB @ 82kHz
• Maximum input 2.9V r.m.s.
• 90k input impedance, 100ohm output impedance
• S-N -102dB unweighted.

Correction (Page 20) The Parts List on Page 27, the value of the X2 type suppression capacitor should be 1nF 250V a.c. The power supply circuit (Fig 4) is correct.

 

Electrosmog Detector - a simple to build circuit will give a comparative reading of most EMFs (electromagnetic fields) that are generated by a wide range of electronic devices that surround us. Cellphones, computers, microwave ovens, fluorescent lighting and electrical power lines can all produce an 'electrosmog' that some individuals are known to be highly sensitive to.

The device was designed to detect EMFs in the region of 0 to 10 mG (milliGauss). Utilising just a few readily available components, this detector will be a fascinating project to build and use.

 

Also in this issue:

• Teach-In 2008 - Using PIC Microcontrollers (4)
• PIC n MIX — using "static" LCDs with PIC microcontrollers
• Circuit Surgery concluding our discussion of SPICE simulation
• Colossus and Pico - the world's first programmable electronic computer is reborn, helped along by the intervention of a modern Pico Technology ADC.
• Interface - our column for PC users on Visual Basic 2008 Express Edition

 

Source codes 0208.zip

PCB artwork pcb0208.zip

 

PCB artwork

 

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.