Some of The Most Unique Taxi around the World

Sharing some of the most unique taxi around the world

Taxi in Japan, Tokyo.

Taxi in Mexico city.

Taxi in Shanghai, China.

Ferrari Taxi in Malaysia

Seems to be unbelievable when a Ferrari taxi appear in front of you and fetch you to the destination.
Somehow this scenario happened in Kuala Lumpur area, more than 10 lucky person were surprised to get the chance for a FOC Ferrari ride !

Mechanical System Animation Design (Solidworks)

Designing 3D mechanical system using CAD software would visualize your idea in mind into reality.
To make the mechanical system more realistic, animation would help.

The video below shows the animation of the mechanical system designed by me using Solidworks CAD software

If you are interested to make a mechanical animation, kindly reach me at reiz6969@gmail.com
I can provide animation design assistant.

Things You Do Not Know About Germany Made Car

Germany, a famous country when comes to automotive industry.

Several mind blowing facts about Germany automotive industry that you might not heard before...

...and one the fact is, the world first car is made by a Germany engineer, Karl Benz.

Is Korean Car Better than Japanese Car ?

Most of the Malaysian have the perspective saying that Japanese car is better than Korean car in the past decade.

But now, you have to think twice before getting a closer look in Korean cars.

DIY DC Motor Driver

How to make a motor driver by ourselves?
Motor driver is commonly used to control motor. Is not a difficult task to make a simple motor driver by ourselves! Here I would like to share my experience of making a simple motor driver.

First of all, the electronic components will be used are resistors, relay, transistors, capacitors, push button, and diodes. The specification of the components are:

1. 4700 ohm resistor

2. 1000 ohm resistor

3. BC547 NPN transistor

4. 12V relay

5. 0.1 microfarad capacitor

6. 1N4147 diode

7. push button

Figure above shows the schematic of the motor driver circuit. 

+12V and +5V is the power supply to the circuit, D1 and D2 represent 1N4147 diode, R1 and R3 are the 4700 ohm resistor, R2 and R4 are 1000 ohm resistor, C1 and C2 represent 0.1 microfarad capacitor, Q1 and Q2 are BC547 transistors. Terminal NO (normally open) is connected to 12V, terminal NC (normally closed) is connected to ground.

Function of D1 & D2 : act as protection to the relay.

Function of R1 & R3 : pull down resistor that make sure the voltage is 0V.

Function of R2 & R4 : limit the current that flow through the transistor.

Function of C1 & C2 : eliminate the bouncing effect when the push button is pressed and unpressed.

NO is connected to 12V, NC is connected to ground.

Once the circuit is complete, we can supply the 12V and 5V power supply to the circuit for testing the circuit by pressing one of the push button. 

When the lower part push button is pressed, the +5V will pass though the resistor R3 and produce current to the transistor Q2. Transistor Q2 is activated and act like short circuit to the ground. The current will flow through the relay coil from 12V to ground, relay coil now is become electromagnet and switch the terminal to NO which is 12V. Since there is voltage drop across the motor, the motor will rotate.

On the other hand, if we press another push button as shown in figure above, Q1 will be activated and the current flow through the relay coil. The left terminal of the motor will connected to 12V whereas right terminal connected to ground. This voltage drop will rotate the motor in clockwise direction.

Conclusion...
If you wish to build a motor driver circuit as explained above, you can buy the components here:
1. 12V Relay - https://www.sparkfun.com/products/10924
2. BC547 NPN transistor - https://www.sparkfun.com/products/8928
3. 0.1 microfarad capacitor - https://www.sparkfun.com/products/8375
4. 1N4147 diode - https://www.sparkfun.com/products/8589
5. push button - http://www.cytron.com.my/viewProduct.php?pcode=SW-PBM-4N-060601&name=6x6x1%20Push%20Button%204Pin

6. Resistors - https://www.sparkfun.com/products/8374

Controlling DC Brushed Motor

How to control the speed of a dc brushed motor?
The typical dc brushed motor has two terminal, positive and negative. To make the motor run we just need to plug in the two terminals with a dc power supply.
But what if we want the motor to run at different speed? Bear in mind the speed of motor is depend on the voltage supply to the motor. Speed of motor is linearly proportional to amount of voltage supply.

Generally, there are several methods can varies the speed of motor such as potential divider method and pulse-width modulation. Potentiometer is used for application of potential divider to control motor speed, whereas pulse-width modulation is generated from a microcontroller.

pulse-width modulation

Here I would like to describe the pulse-width modulation(PWM) method to control motor speed.

To do so, we need to have a microcontroller chip and a motor driver chip, L293D. This L293D can used to control the speed and direction of two dc brushed motors. 

pinout of L293D

From the pin-out diagram above, output 1 and output 2 is connect motor 1, whereas output 3 and 4 is connect to another dc motor, motor 2. Input 1, 2, 3, and 4 each has to connect to pin of microcontroller. These four pins are used to give signal to L293D to control the rotational direction of motor. Enable 1 is the PWM signal port for motor 1, enable 2 for motor 2. These two port have to connect to the PWM output port of the microcontroller.