BLOG · 28/12/2024

D-P-001 Level-0 (Part-2)

A continuation of my marvel report

Virajit G.P

This Article is yet to be approved by a Coordinator.

Task-10: Speed Control of DC Motor

Parts Used:

DC Motor: This is the device being controlled. A DC motor is an electrical machine that converts direct current electrical energy into mechanical energy. It operates on the principle of electromagnetic induction, where current flowing through a wire induces a magnetic field that interacts with another magnetic field to produce motion.
L293D Motor Driver IC: This is a dual H-bridge integrated circuit used to control the speed and direction of the DC motor. An H-bridge is a circuit that allows voltage to be applied across a load in either direction. The L293D has four input pins (IN1, IN2, IN3, IN4), four output pins (OUT1, OUT2, OUT3, OUT4), and two enable pins (EN1, EN2). It can handle up to 600mA of current per motor and operates with a supply voltage between 4.5V and 36V.
Arduino Microcontroller: Specifically, the Arduino Uno is a board that sends control signals to the L293D. The Arduino Uno is a popular open-source microcontroller board that can be programmed to control various electronic components.

Basic Principles:

H-Bridge Operation: The L293D uses an H-bridge circuit to control the direction of the motor's rotation by changing the current flow through the motor's terminals. By selectively activating different switches within the H-bridge, current can be directed through the motor in either direction, resulting in forward or reverse rotation.
Pulse Width Modulation (PWM): The speed of the DC motor is controlled using PWM. PWM rapidly switches the power to the motor on and off, varying the duration of the "on" time (pulse width) which adjusts the average power supplied to the motor, and thus, its speed. The Arduino generates these PWM signals on its digital output pins.
Direction Control: The L293D controls the direction of the motor by sending current in either direction through the motor's terminals. The direction of the current determines the direction of rotation.
Power Supply: The L293D requires a power supply with a voltage between 4.5V and 36V. The VCC1 pin supplies power to the control logic of the IC, while VCC2 supplies power to the motors.

##TASK-12: SOLDERING

Soldering joins electronic parts by melting solder, a metal alloy, to create a strong electrical bond.
A soldering iron heats up to melt solder, and a pen style in the 15W to 30W range is recommended for beginners.
Soldering stations provide more control, including adjustable temperature settings and safety features.
Soldering iron tips come in different shapes and sizes, such as:
- Conical tips for precision electronics.
- Chisel tips for wires and larger components.
A brass sponge is used to clean oxidation from the soldering iron tip.
A soldering iron stand is used to prevent burns and contact with flammable materials.
Solder comes in lead and lead-free options, with rosin core solder being the most common type for electronics.
Acid core solder should not be used for electronics as it can cause damage.
Solder diameters of .032" and .062" are most common.
Helping hands, with alligator clips, can hold items in place while soldering.
Safety precautions when soldering:
- Use a soldering iron stand.
- Work in a well-ventilated area.
- Wear protective eyewear.
- Wash hands after soldering.
Tinning the tip of the soldering iron with solder improves heat transfer and protects the tip.
To solder, heat the joint, apply solder to the joint (not the iron), and let it cool.
A proper solder joint is smooth and shiny, resembling a volcano or cone shape.
To solder wires, remove insulation, tin the ends, then solder the tinned wires together.
Desoldering uses solder wick or a solder sucker to remove solder.

TASK-13: 555 TIMER

Oscilloscope Reading

Circuit Diagram

The 555 timer IC is a versatile integrated circuit that can be used in a variety of timing applications. The 555 can be connected in three modes: monostable, bistable, or astable. When connected in astable mode, the 555 timer functions as a free-running oscillator, continuously producing a square wave output. This is achieved by connecting the trigger input (pin 2) and the threshold input (pin 6) together, allowing the device to act as an astable oscillator. In this mode, the 555 has no stable states, continuously switching from one state to another.

In a basic astable 555 oscillator circuit, a capacitor charges through two resistors, R1 and R2, but discharges only through R2. The capacitor charges up to 2/3 Vcc and then discharges down to 1/3 Vcc. The output waveform's voltage level is approximately equal to Vcc - 1.5V. The timing for the charge and discharge cycles is determined by the resistor and capacitor combinations.

Basic Operation: The 555 oscillator is triggered by connecting pins 2 and 6, which allows the device to retrigger itself continuously.
Charging: The capacitor charges through both resistors R1 and R2.
Discharging: The capacitor discharges only through resistor R2.
Output: The output at pin 3 will switch between high (approximately Vcc - 1.5V) and low (close to 0V).

The basic astable 555 oscillator configuration has a limitation where the duty cycle cannot go below 50%. The duty cycle, or "mark-to-space" ratio, is the ratio of the "ON" time to the total cycle time.

To improve the duty cycle, a diode can be connected in parallel with resistor R2. This allows the capacitor to charge through R1 only. If needed, a second diode can be added in series with R2 to ensure that the capacitor does not charge through R2. This changes the charging time and the duty cycle is then determined by the ratio of R1 to R1 + R2.

A 50% duty cycle can be achieved without extra diodes by moving resistor R2 to the output pin (pin 3). In this setup, the capacitor charges and discharges through the same resistor, R2. The resistor R1 ensures the capacitor charges up fully to the supply voltage.

The following equations describe the operation of the standard 555 astable multivibrator:

Charge Time (t1): t1 = 0.693 * (R1 + R2) * C This is the time the capacitor charges from 1/3 Vcc to 2/3 Vcc through resistors R1 and R2.
Discharge Time (t2): t2 = 0.693 * R2 * C This is the time the capacitor discharges from 2/3 Vcc to 1/3 Vcc through resistor R2.
Total Cycle Time (T): T = t1 + t2 = 0.693 * (R1 + 2R2) * C The total time for one full charge and discharge cycle.
Frequency (f): f = 1 / T = 1.44 / ((R1 + 2R2) * C) The frequency of the output waveform.
Duty Cycle (D): D = t1 / T = (R1 + R2) / (R1 + 2R2) The ratio of the "ON" time to the total cycle time. The basic duty cycle equation is also given as: D = R2 / (R1 + R2).

TASK-14: KARNAUGH-MAP

Let' have a look at the 4 cases:

Door(D) | Key(K) | Alarm(A)
   0    |   0    |    0   (Locked, No key - Safe)
   0    |   1    |    0   (Locked, Key - Safe) 
   1    |   0    |    1    (Open, No key - Unsafe)
   1    |   1    |    0    (Open, Key - Safe)

Door: 0 - close 1 - open Key 0 - not on door 1 - on door Alarm 0 - off(safe) 1 - on(unsafe)

K-map:

K/D | 0 | 1
  0 | 0 | 0
  1 | 1 | 0

Boolean expression from K-map: A = K + D̄ (Key pressed OR Door locked)

graph LR
    D[Door Button] -->|D| OR
    K[Key Button] -->|K| OR
    NOT[NOT Gate] -->|D̄| OR
    D --> NOT
    OR --> LED[LED/Buzzer]

To build this:

Connect door button to NOT gate and OR gate
Connect key button to OR gate
Connect NOT gate output to OR gate
Connect OR gate output to LED/buzzer

The alarm activates when the door is locked OR when the key is pressed.

Note: or use a XOR gate

TASK-15: Active Participation

Certificate of Participation

TASK-16: Datasheet Repot Writing

Name: L293D

Logic Diagram

Def: The L293D is an "Motor Driver" designed to provide bidirectional drive currents of up to 600-mA at voltages from 4.5 V to 36 V.(the Imax for L293 is 1A)

Function: to drive inductive loads such as relays, solenoids, DC and bipolar stepping motors and other high current/high voltage loads in +ve supply applications.

Features:

Wide Supply-Voltage Range: 4.5 V to 36 V
Internal ESD Protection
Separate Input-Logic Supply 
Output Clamp Diodes for Inductive Transient Suppression

Applications:

Stepper Motor Drivers 
DC Motor Drivers 
Latching Relay

Pin Configuration:

Task 17: Introduction to VR

VR uses special headsets with screens for each eye to create a 3D view, making you feel like you're in a different place.
Motion tracking is how VR keeps up with your movements, like your head turns. It's like VR has its own "eyes and ears" watching how you move.
Input devices are used to interface with the virtual world
Spatial audio surrounds you with sound from all directions, making the experience more immersive.
Haptic feedback simulates the sense of touch through vibrations or motions. This makes digital interactions feel more real.
Rendering engines generate images from 2D or 3D models. They create the graphics you see.
Latency is the short delay between your actions and the virtual world’s response. Keeping this delay as short as possible is important for a seamless experience.
Field of View (FOV) allows you to see more of the virtual world without constantly turning your head. A wide FOV makes the virtual world more immersive.
Six Degrees of Freedom (6DoF) lets you move naturally in the virtual space - forward, backward, up, down and all around.
notable Indian startups in the AR/VR industry are Quytech, Awakeen Studio, AjnaLens, Simbott, Avataar, StreakByte, and Space-O Technologies.