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Your One Stop Solution for Circuit Board Design, Development & Manufacturing

Jaavin Electronic Solution



A blog brought to you by Jaavin Electronic Solution about electronics and the latest trends in the electronic industry.

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Modbus IO Card Design

Posted by Aravin on 8 July, 2014 at 4:35

Modbus IO card functions as an interface between main controller and discrete level IO devices such as relays, solenoids and devices with HIGH and LOW inputs/ outputs. Using the robust industry standard Modbus communication protocol, these IO devices can be controlled and monitored remotely by PLC and computers.

Our engineering team have recently designed and developed a simple digital I/O card with modbus and RS-232 communication.This card has 32 isolated digital inputs and 16 isolated digital outputs.

Simple Modbus IO Card Block Diagram

Completed Modbus PCB


Here are some demo videos:

Function: 01 Read Coils

This function allows you to read the input status if it is HIGH or LOW. The video shows the input status on the Modbus Poll software changes from 1 to 0 when the corresponding input pins is connected to 0V. When an input is connected to 0V the corresponding input LED on the board lights up. All 32 inputs is being activated one by one.

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Function: 05 Write Single Coil


The video demonstrates how to activate an output each at a time. The address range is 0-24 for all the 24 outputs. To activate say output 3, enter 3 in the address field and set the value ‘on’. The corresponding output LED will light up.


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Function: 15 Write Multiple Coils


The video demonstrates how to activate multiple outputs. All twenty four outputs were activated at once in this video. The board can be customised to suit to the end application.


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 Function: 17 Report Slave ID

This video demonstrates Report Slave ID function that returns a description of the type of controller present at the slave address, the current status of the slave Run indicator, and other information specific to the slave device.

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Feel free to contact us for any further enquiry on modifying this board to suit to your industry requirements.

How the Penang Free Trade Zone started?

Posted by Aravin on 1 April, 2014 at 2:55

I came across an interesting article published in the July 2013 edition of JURUTERA (buletin of the Institute Of Engineers, Malaysia) about the Malaysian Electrical & Electronics Industry. It mentioned about how the Penang Free Trade Zone came about and eventually the growth Electrical & Electronic industry in Malaysia.

Here is a small extract from it (original article and photo by Dato' Wong Siew Hai, Chair of Malaysian American Electronics Industry)

In 1969, as the federal goverment of Malaysia had revoked the Penang Free Port Status, the unemployment rate at that time was around 15% against the national average of 9%. The Chief Minister at that time, Dr Lim Cheong Eu was faced with this challenge and he needed to find a solution to create more job opprtunities. Dr. Lim had this vision of setting up some industrial parks, known as the Free Trade Zone (FTZ, now called Free Industrial Zone,FIZ) located in Bayan Lepas, Penang.

Subsequently Dr. Lim established the Penang Development Corporation in November 1969 to promote the FTZ and to attract foreign direct investments (FDIs) with pioneer status given. The labour cost was very low at that time and this idea of FTZ industrial parks was later extended to Selangor and Malacca.

Dr. Lim and his team made numerous trips overseas especially to USA, Europe and Japan to promote the FTZ and many small & medium enterprises (SMEs) came to visit the FTZ. One of the companies was Intel. Andy Grove, then CEO of Intel visited the location. There was heavy rain the night before. The picture shows that his car was stuck in the mud as the road was not paved and he had to roll up his pants to walk as he visited the site, which basically was still a coconut plantation in the process of being cleared for the use of the industry.

There was a leap of faith when the companies decided to start up their factories in the Penang FTZ in 1972 although the site was not even ready to be used. This decision marked the start of the E&E industry in Penang and in Malaysia.

The first eight companies that came to Penang FTZ were Advanced Micro Devices (AMD), Hewlet Packard (now called Agilent Technologies), Clarion (M), National Semiconductor (now called Fairchild), Hitachi (now called Renesas), Intel, Litronix (now called Osram Opto Semiconductor) and Robert Bosch.

The good news is all of the first eight companies are still around and growing although some were restructured or acquired with company name changed.

My humble self is proud to be associated with Penang FTZ as I started my career as an electronic board design engineer in Robert Bosch from 2001 till 2006.

GPIO Expansion Board - Add Muscle to Your Raspberry Pi

Posted by Aravin on 23 January, 2013 at 4:35

Raspberry Pi - Image courtesy of

The Raspberry Pi single board computer is a low cost yet a powerful hardware with ethernet, USB, audio, video and HDMI. Although it has many interesting features, there are some limitations when you need to drive relays, motors or LEDs for example. The Raspberry Pi has several GPIOs that can be utilised. However its voltage range is between 0-3.3V and has a maximum sinking current of 16mA. You need higher current than this to drive the relay coil.

For input signals from devices such as analogue sensors, its output voltage range may be too low or high to be connected directly to Raspberry Pi's GPIO. The audio output from this board is adequate to drive small earphone speakers. You will require an amplifier to drive higher wattage speakers.

Now, there may be many different requirements from users. We can customise the expansion board to suit to your requirements. Just tell us the peripherals/devices that you intend to connect to Raspberry Pi board so we can help to custom design the PCB for you. Check out here an example of an expansion board that we have tailor made. Interested? Contact us.

How to Estimate Static and Dynamic Current Consumption of a Printed Circuit Board?

Posted by Aravin on 19 December, 2012 at 8:55

By Aravinthan Varatharaju, Electronic Design Consultant in Jaavin Electronic Solution

When designing circuits often the hardware engineer need to know the current consumption of the printed circuit board being designed. Current consumption is an important parameter to determine the type of power supply solution and the power rating of the components. Secondly it is used to determine the power trace width when doing PCB layout design. More importantly if the board is to be powered by battery, current consumption data is crucial to estimate battery life.

The most common method of determining current consumption during pre-design stage is by checking the IC manufacturer’s datasheet. The datasheet will normally state the current consumption when in normal operation. Some manufacturers will provide typical and maximum value. For some special function ICs such as RF transceivers, a list of different values depending on the modes such as transmit, receive, idle and sleep will be stated. In this case the worst case current consumption needs to be considered in the calculation.

Sum up the current consumption of all the ICs used on the board. Also check the other discrete circuits such as LED drivers, transistors and relay circuits which may consume significant power. Make sure to include the worst case current scenario. For instance assume that all the LEDs or transistors are switched on when calculating the current. Current consumption by high impedance circuits and high value pull-up resistors can usually be ignored.

The above method is fairly easy due to its steady state estimation during pre-design stages. The hardware engineer will then chose component ratings to be at least twice the actual value for a safe design. The above method however cannot be used to estimate battery life if the boards current consumption is dynamic. In an embedded design, the current consumption will be based on the firmware that controls the function of the board.

Say for instance we take a battery powered RF beacon transmitter board. The microcontroller is programmed such that it ‘wakes’ up every second to transmit data for 10 microsecond and goes to sleep mode until the next one second interval. The current draw is 30mA and 1µA during transmit and sleep mode respectively. There may be an intermediate period where the microcontroller is initialising and processing data before transmitting, which is why it is better to measure actual current consumption than to estimate theoretically.

In order to calculate battery life, the average current consumption of the board need to be determined. There are current measuring equipments that will be able to measure in wide dynamic range from µA to A to provide the average current automatically. Unfortunately these equipments are not common laboratory equipment. For very low power boards consuming <50mA, there is an alternative method to measure and calculate average current by using the common DSO (Digital Storage Oscilloscope)

Figure 1: Measurement setup

Figure 1 shows an example of the setup. A 10 Ohm resistor is connected in series between positive terminal of DC bench power supply to the positive power terminal of the board (Device Under Test, DUT). The probe of the DSO is connected parallel to the 10 Ohm +/-1% resistor to measure the voltage drop across it. Set the oscilloscope to capture the waveform. Since the waveform is periodic, only one waveform of a period is required. Next, sketch the waveform approximating it to straight lines.

Figure 2: Waveform of voltage drop across 10 Ohm resistor

Figure 2 shows an example of a 1 second periodic waveform of a RF transceiver that transmits every second. The waveform is simply the voltage drop across the 10 Ohm resistor of which the current is calculated using Ohm’s Law.


Split the waveform into sections with the same amplitude. For each section, note down the current and the time as shown in Table 1. Also take note of the period, T. Do take note that it is difficult to read the voltage drop VR during ‘sleep’ mode because the amplitude is almost zero. To tackle this, just add up the ‘sleep mode’ current consumption stated in the datasheet of the microcontroller and related ICs. In this example the sleep mode is 1µA.


Table 1: Amplitude, current and time of each sections

Now to calculate the current, one need to just sum up the area under the curve and divide by the period. Table 2 displays the area calculation of each section and how the average current is derived.

Table 2: Average current derived from the sum of area under the curve

This average current can now be used to calculate battery life. Figure 3 shows an example of battery lifetime calculation using CR2032 battery with the average current estimated just now. The method can easily be adapted with other battery types.

Figure 3: Battery life calculation

The measurement technique illustrated in this article does have its limitation. For boards that draw higher than 50mA, the voltage drop across 10 Ohm resistor exceeds 0.5V. This may cause the board to shut down due to under voltage. Using 1 Ohm resistor may not be a good idea because it will be difficult to see the amplitude when the current draw is less than 50mA. Perhaps a differential amplifier circuit with suitable gain can be used to get the voltage drop reading across the resistor. Bear in mind that the gain introduced must not be too high that it will cause the amplifier output to saturate when the current draw hits peak value. Better still Hall Effect Current sensors can be used to replace the resistor. Another limiting factor is if the current draw is not periodic then this technique is not suitable.


Getting to know IP address - Vol 1

Posted by Aravin on 4 September, 2012 at 4:40

This article is contributed by Mr. Lee Heng Wai

Basic IPv4 Address


Why we need IP address?

According TCP/IP model, network layer try to guide the packet from source all the way to the destination


How to achieve it?

Network layer must know topology of network.


Through internet, a computer somewhere in the world needs to communicate with another computer some else in the world.


In order to implement this, the computers have to be connected to the Internet, and we need a global addressing scheme, so that computers able to identify their locations.


In order to let computers can talk to another computer, the IP addressing schema must have those characteristic.

1) Unique: In order to connect to Internet, you have must have one and only one IP address.

2) Universal: This addressing scheme must be well accepted by any host.


Here, we will discuss about IP addressing scheme which based on RFC791, Internet Protocol. The version discussed is IP version 4. We have another new version which is IPv6, we will not discuss here.


What is IP address?


IPv4 has 32bit, which is something like this

11000000101010000011100 01000101 (all in binary terms)


This 32 bit binary numbers are understandable by computer easily.

Problem is we as human being, and we are not going to memorise these numbers (unless you are a genius).


So what we need to do is convert to certain format by dividing those numbers into 8 bit per chunks. Each chunk is separated by dot notation.


This 8bit per chunks, the highest value is 128 and the lowest value is 1. And we have to convert those 8 bit into decimal value, so the range is 0~255.

After we convert, we will get this result:

This format is much easier and readable compare to binary numbers.


The IPv4 decimal notation format as below:


where X has range from 0 to 255.


IP address has 2 part. One is network part, or NetID or Prefix, another part is host part or HostID, or suffix.

So what is NetID and HostID?

You can imagine house is HostID, each house has house number.

House 101 ‘s neighbour is House 102. Both of them located on a street name 100, this is NetID.

So people in the house 101 want to talk to people in house 102, he just directly walk to house 102.

Look at this example:

So people in the house 101 want to talk to people in the house 202, so what he need to do is he have go out to street 100 then pass the junction which is connected to street 200. From the street 200, then he can go to house 202.

So, let say you have cross a junction something like below, so how do you know which street you need to go? This can be solved by so called Street Sign. In IP world, we called it IP routing table, which contained inside a special device, called Router.


In human world, our home address may consist of country, city, postcode, street name, and house number. But, for IP, it is very special, it just contain only street name and house number. Street name is NetworkID, house number is HostID. Few houses may locate on the same street, same thing to PC. Few PCs may have the same network segment. When across the street, you need to pass the junction first, or PCs in different network segment to be communicated, they are interconnected through router.


Getting to Know LabVIEW

Posted by Aravin on 10 July, 2012 at 12:00

On 10th July 2012 we attended the Labview and Fundamentals in Data Acquisition Workshop hosted by National Instruments Malaysia. The venue was at their PJ office.

We were given an excellent overview by the presenter Mr. Manickavasagam Kannappan, NI Field Application Engineer.


Labview together with NI's I/O hardware (about 6000 various types) is a powerful yet easy to use tool for data acquisition system.


Labview being a graphical based design system, eliminate the need to develop software coding using conventional method.

Apart from that, it is a highly integrated solution for sensing data, processing, analyzing, displaying and reporting.


Javin Electronic Solution would like to thank NI for inviting us to this workshop.

We hope more workshops covering other topics will be organised in the future.

We look forward for enquiries requiring our services to provide NI based measurement solution.



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Camera On Your Eye

Posted by Aravin on 8 July, 2012 at 23:35

First the digital camera, then cameras on mobile phones and now comes camera on glass.

 Soon this humble eye glass will transmute to a hi-tech piece.

Google and Olympus has been working on the prototypes.

Called Project Glass, the idea behind this is you have a wearing glass fitted with camera daylight viewable QVGA display with a resolution of 320 x 240, Bluetooth 2.1, a built-in accelerometer, GPS.


Eventually, this will be the evolution for smartphone.


As shown in the video below, with a wearable camera, you can capture real time moments anytime.

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Read more here:

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Spray it on any surface and it becomes a rechargeable battery

Posted by Aravin on 3 July, 2012 at 2:15

Regular batteries may one day become a thing of the past

To make a battery, just spray a chemical substance on any hard surface and it becomes a battery! Now this is what a research team has accomplished. They have successfully air-brushed chemicals similarly found in rechargeable battery almost on any surface such as the mug, bathroom tiles, beer cans and what not.

Now imagine what is the impact if this technology can be commercialised?

You can spray-on the battery chemical on your house roof to transform it to a huge rechargeable battery. Fitted with solar panel, it can then charge your 'roof' battery.

Cellphone and laptops need not have battery compartments. Just spray it on the housing and it becomes its battery.

Electric cars need not carry heavy batteries as the car body acts as the battery.

Still at its infancy

This technology is still at its infancy as the chemical is hazardous. Once researches find a way to coat it with inert material then it will be ready to hit the market. You can then buy the 'battery' in a liquid form to transform any object to an energy storage.

Read more here



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Charging Phone on Thin Air?

Posted by Aravin on 27 June, 2012 at 7:30

In future you can just place the phone on the desk for charging

If you read my earlier blog post on wireless power transfer  here, I was saying that this technology is still at infancy and few companies are working on this to improve.

The problem is inefficiency because you loose power when transmitting on air. Although this is an obstacle, the thought of putting your phone on a table without plugging it and the phone just get charged like that is very appealing.

So much so, Apple is now working on this technology for its next iPhone. Read here.

For now there will be a charging dock where the phone had to be placed on. I believe soon there will be concealed docking pads placed everywhere on tables in reataurants, cafes and airports.

Just What is A Smart TV?

Posted by Aravin on 26 June, 2012 at 7:40

Smart TV is a hybrid between a TV and Internet. A smart TV offers the best in video and internet connectivity at the same time.

The principle behind this is you get to watch anything at any time and not dictated by the TV broadcaster. At the same time you can give comments, feedback, rate on the show you watched and share among your friends just like in the net.

You can discuss the show ‘live’. You can shop on the fly when you see any interesting product advertised.

The TV will track your viewing pattern and will make viewing recommendations.

You can surf the internet with your remote. Share videos and photos with online friends.

In a nutshell, Smart TV offers videos, photos, movies, music, internet and social networking.

Watch the video here

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