Development of Multi Sensor Blind Stick

Sunday, 21 April 2013

S'2 WEEK 14 => 15 APRIL - 21 APRIL

11:59 Unknown No comments

I will be working on my FYP report, it’s going to take time but I will try my best to finish it earlier as Dr.Zulkhairi requested.

After that I need to submit a hard and a soft copy to the library for my FYP report.

later on in shaa Allah i will post a picture of my FYP report.

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This is the update for the FYP hardcover

S'2 WEEK 13 => 8 APRIL - 14 APRIL

11:59 Unknown No comments

This week is about preparing for the finale year project presentation.

And after that present all what I have done to my assessors, ustaz.Kamal and mdm.Zaridah .

S'2 WEEK 12 => 1 APRIL - 7 APRIL

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The FYP poster :

S'2 WEEK 11 => 25 MARCH - 31 MARCH

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S'2 WEEK 10 => 18 MARCH - 24 MARCH

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S'2 WEEK 9 => 11 MARCH - 17 MARCH

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VOLTAGE REGULATOR

The voltage regulator module is used to protect PIC and other connected sensors / actuators from over voltage. This is because PIC and all other connected sensors, actuators all support 5V DC only. Over voltage will cause any of the module burn.

Voltage Regulator

LM7805 is used to regulate voltage in the system and output 5V DC (max output current: 1000mA). It supports input voltage from 7V DC to 18V DC. If the input voltage is over, the LM7805 will burn or auto shutdown due to overheat. The generated 5V from LM7805 will be noise filtered by 0.1uF ceramic capacitor and a 1000uF electrolytic capacitor. This is to avoid high frequency oscillation on the outputs which may cause system hang or unstable.

The generated 5V from LM7805 will be noise filtered by 0.1uF ceramic capacitor and a 1000uF electrolytic capacitor. This is to avoid high frequency oscillation on the outputs which may cause system hang or unstable.

A diode is connected at the input of the LM7805. This is to avoid voltage connected reversely. An on/off switch is used to turn on/off the system and a LED (5V, 5mA) is used to indicate the system is power on/off. The LED is connected through 1KR resistor to limit current pass through LED is 5mA.

S'2 WEEK 8 => 4 MARCH - 10 MARCH

11:53 Unknown No comments

The H-Bridge

The original concept of the H-Bridge was being able to control the direction a motor was going. Forward or backward. This was achieved by managing current flow through circuit elements called transistors. The formation looks like an H and that's where it gets the name H-Bridge. Here is what it looks like:

The picture above illustrates the 4 base cases that we can get out of the simple version of an H-Bridge. The two cases that interest us are when A & D are both 1 and when B & C are both 1.

When A & D are 1 current from the battery will flow from point A through the motor to D's ground. However for the case when B & C are both 1, current will flow in the opposite direction from B through the motor to C's ground.

The L298 Motor Driver

At below you'll see a sample the H-Bridge with looks like with each pin labeled.

The advantage that the HN offers is that all the extra diodes typically necessary with a standard L298 circuit are already internally in the chip. It saves us as designers an extra element for the motor control circuit.

Varying DC Motor Speed

Pins 5 & 7 in the chip pinout above are inputs 1 & 2 respectively. These inputs take what is called a PWM input. The frequency of the PWM is dependant upon the motor. For our motor we'll use a 1 KHz input frequency. This means the motor speed will be updates 1 thousands times a second. The duty cycle of the PWM will determine the speed & direction of the motor.

Development of Multi Sensor Blind Stick