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Electronics Project and Design, Issue #002
May 22, 2006

Issue #002
21st May 2006

Welcome to the 2nd issue of Electronics Project and Design. I know this 2nd newsletter is slow in coming to you and I would like to thank you for being so patient. I have been busy updating the website with many new projects and relevant information pertaining to electronics project design. If you have not visited the site for quite a while, do pay a visit now and check out the new projects recently uploaded.

In this issue :
1. New Project
2. Tips and techniques
3. Latest updates on


For this issue, we will look into a Hold Telephone Circuit that will enable you to hang up one phone without losing the connection and move to another room or hall and pick up a different phone which is connected in parallel and continue your conversation. This feature is useful especially when you are staying in a house with different levels and having 2 telephones connected in parallel.

This project uses a silicon controlled recifier or SCR which is connected in series with a light emitting diode (LED) and a potentiometer. It is a simple project that uses only 5 electronic parts.

You can get the detail schematic and parts list of the project from the link below.

2. Tips and Techniques

In the design of electronics project, it is very common to use a keypad matrix as a means for user to interface to the product. In order to minimize the number of pins used in the microcontroller, the keys should be arranged in as square a matrix as possible.

One example is the use of 4 X 4 matrix arrangement in a 16 keys keypad. This arrangement requires only 8 pins. If it is arrange in a 2 X 8 matrix, 10 pins will be needed instead of 8. By looking at the example of the flow chart and how the programming of this is done, one will be able to understand and learn how to design a cost effective keypad scanning using any microcontroller.

You can get the detail of the technique from the link below.
Microcontroller Keypad Decoding Tips

3. Latest Updates on

Music Generator, Audio Signal Tracer, Variable Frequency Signal Oscillator

Electronic Project Enclosures

Free Electronics Design Software

Remember to check back often for more updates on

If you find any of the above information useful, please feel free to forward it to your friends.

If a friend forwarded this to you, you may want to subscibe to this newsletter yourself and have future issues sent directly to your mailbox. Please subscribe HERE.

See you in the next issue. :-)

All the best,
Michael S.

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