Project Solutions

VHF-Low Explorer （1）

Published:2011/7/28 20:41:00 Author:Phyllis

By Gert Barrs A low-cost NBFM receiver for 68-88 MHz This article, we hope, will have serious consequence. Not negative, mind you, because apart from enabling beginners to experience the thrill of picking up radio traffic in a generally neglected band, the arrival of this inexpensive 4-m receiver should help to get the IARU section of the 4-m band released...   (View)

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Sensors Go Systematic （5）

Published:2011/7/28 5:25:00 Author:Amy

By Helmuth Lemme However, it is also possible to use die actual fibre as the meas­uring element. Such intrinsic” fibre-optic systems exploit the miniscule but still present effects of external physical quanti­ties on the propagation of light through the fibre. If the wave nature of the light is also taken into account, very high sensi­tivity and resolution can be achieve...   (View)

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Sensors Go Systematic （4）

Published:2011/7/28 5:21:00 Author:Amy

Modular construction Despite iis considerable success, there is a problem with microsystem technology, which is that the large front-end development costs can only be recovered if the components are produced in large quantities. This is difficult to achieve for small and medium-sized sensor manufacturers. One solution to this problem is to construct the sensors in modular form usin...   (View)

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Sensors Go Systematic （3）

Published:2011/7/28 3:07:00 Author:Amy

By Helmuth Lemme Bus connection In systems with many sensors, it is economical to connect all of them to the computer via a common bus, rather than using individual cabling. This means that each sensor must have a bus coupler, which in many cases can also be housed on the chip. An early example of this type of component was the National Semiconductor LM75, which had a delta/sigma...   (View)

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Sensors Go Systematic （2）

Published:2011/7/28 2:25:00 Author:Amy

By Helmuth Lemme Signal conditioning Amplifying the signal is not the only task of signal condition­ing. .Many of the physical effects utilised for sensors are tem­perature dependent. To compensate for this, a temperature sensor that suitably adjusts the gain can be incorporated into the system. In many cases, the transfer characteristics are non-linear and must be linearise...   (View)

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Sensors Go Systematic （1）

Published:2011/7/28 2:10:00 Author:Amy

By Helmuth Lemme Under the increasing time and cost pressures imposed on developing instrumentation devices, building preamplifiers for sensors is increasingly coming to be seen as an irksome secondary task. They must be exactly matched to the sensor output signals, which are usually weak, and if a different type of sensor is used, the entire job has to be done all over again. A far more u...   (View)

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Elektor Electronics Year Volume CD-ROMs on Hard Disk

Published:2011/7/28 2:07:00 Author:Phyllis

Faster & comprehensive access By Harry Baggen The Elektor Electronics 2003 CD-ROM has a useful extra for even easier use of several earlier volumes people may already have. It is now possible to copy most of our year volume CD-ROMs to hard disk using the program Diskmirror supplied. With a few tricks, you can even do so using relatively little hard disk space. Elektor...   (View)

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FlexiPanel IR Infrared glue for micros and PDAs （2）

Published:2011/7/28 1:36:00 Author:Amy

By Jan Buifing and Luc Lemmens BASIC Stamp Not just to underline their business relation with dis­tributor Parallax Inc., but also to encourage lab work­ers, Hoptroff provide lots of information on linking the Flexipanel to the famous BASIC Stamp. And a very welcome bit of information it is because the BASIC Stamp (BS2p) is widely known and extremely popular among budding pr...   (View)

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iAccess--an intelligent access control system （4）

Published:2011/7/28 1:17:00 Author:Li xiao na

Design by I. Joostens Construction, alignment and commissioning The circuit is built on a double-sided printed circuit board with plated-through holes, which is illustrated in Figure 4. Despite the complexity of the schematic diagram, assembling the board should not present any significant problems. Use IC sockets for all ICs and check that the values and polariti...   (View)

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Varicap selection or the delta-C / delta-V issue

Published:2011/7/28 1:15:00 Author:Phyllis

For some strange reason varicaps (or variable capacitance diodes) have always been rather elusive components. Try this: design, engineer and publish a design at instant T and you’ll find that the varicap you’ve specified after hours of careful researching has disappeared from the market at [T+1 day]. Here at Elektor we’re optimists by nature but because we anticipate supply problems with the BB911 varicap specified...   (View)

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iAccess--an intelligent access control system （3）

Published:2011/7/28 0:52:00 Author:Li xiao na

Design by I. Joostens Schematic diagram Buffers, logic and drivers A ULN2803 (IC4) is used as a driver IC for the various indicator LEDs and the output relay. This IC contains eight open-collector drivers, each of which can switch a maximum current of around 500 mA. IC11 and IC12 are included because the microcontroller I/O pins cannot supply enough current in t...   (View)

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iAccess--an intelligent access control system （2）

Published:2011/7/28 0:39:00 Author:Li xiao na

Design by I. Joostens Schematic diagram The full schematic diagram of the system is shown in Figure 3. The functional blocks shown in Figure 2 can be recognized here without too much effort. The most important elements are described in more detail below. Microcontroller, user interface, RS232 interface and...   (View)

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iAccess--an intelligent access control system （1）

Published:2011/7/27 22:39:00 Author:Li xiao na

Design by I. Joostens Surveys show that people are feeling increasingly less safe. Consequently, protecting property and buildings receives more and more attention these days. One of the aspects of such protection is access control. The system described here goes further than most such systems. Besides granting persons selective access to specific areas, iAccess allows you to check ...   (View)

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Audio Power Amps on the Internet

Published:2011/7/27 22:33:00 Author:Phyllis

Fewer components, better sound? By Harry Boggen Audio lovers will no doubt drool over the new Elektor preamp with digital control published in this issue. This, of course, calls for a matching power amplifier! Sure, there are enough high-quality Elektor designs to choose from, but it may also be interesting to trawl the Internet for alternative designs from all over the world. (View)

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Parallel Port Mains Switching Interface--switch radio controlled mains sockets on and off from a PC （3）

Published:2011/7/27 22:20:00 Author:Li xiao na

by K. Heiden Construction The simplest way to construct the interface circuit is to use matrix stripboard. The components are all widely available and so should be easy to obtain. A suitable latching relay for RE1 is available for example from Conrad Electronics (order code 50 40 60). For RE2 practically any small 12 V relay can be used. As can be seen from the circuit diagr...   (View)

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Drop-in Microcontroller Board （3）

Published:2011/7/27 21:39:00 Author:Phyllis

Building it Having purchased the printed circuit board and all components you are ready to start building the circuit. As shown in Figure 4, the PCB consists of two sections that are easily separated using a hacksaw. One section is for the interface with the PC, the other, for the drop-in module proper. (View)

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Drop-in Microcontroller Board （2）

Published:2011/7/27 21:35:00 Author:Phyllis

Hardware The starting point for your experiments with this chip is a piece of hardware we developed that could be ’dropped’ into several circuits. The circuit diagram of the drop-in module may be found in Figure 2. Even a cursory glance at the drawing should convince you that simplicity is trumps. Thanks to the multifunctional character of the PSD813 chip, this bit of hardw...   (View)

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Drop-in Microcontroller Board （1）

Published:2011/7/27 21:29:00 Author:Phyllis

An 80C32 jack-of-all-trades At the heart of this remarkably compact microcontroller board you’ll find an ingenious bit of integration technology. The combination acts as a versatile plug-in module for lots of applications requiring some form of intelligent control. Thanks to the extensive software that comes with the board and the presence of a PC interface, our drop-in board is excellent for hardw...   (View)

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FlexiPanel IR Infrared glue for micros and PDAs (1)

Published:2011/7/27 4:13:00 Author:Amy

By Jan Buifing and Luc Lemmens IrDA sure looks like an attractive medium for conveying data across small distances. Unfortunately, the associated hardware gener­ally causes sour faces, and is not just ’playing’ hard to get. Those days are over. Paris-based Hoptroff sarl (in the UK: Flexipanel Ltd.) recently announced the release of an IrDA module (also called ‘irGUI module’ or ‘...   (View)

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Up, Up and Away

Published:2011/7/27 3:38:00 Author:Amy

By David Daamen Telemetry applied to modelling sometimes pro­duces astounding results — especially if elec­tronics is part of the payload... Model construction and electronics seem to get on like a house on fire, new challenges appearing any time these two fields of interest are combined. The results are often rather spe­cial. For example, Olivier Humez on his website |1...   (View)

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