Details : MCU + peripherals

Week 1

Week 2

-

Week 3

-

Week 4

-

Basics on motors

Other notes regarding motors could also be seen at Week 10 : Output Devices.

Feature	Hobby Servo Motor	Stepper Motor
Typical Motion	Limited-angle rotation (positioning servo) or continuous rotation (modified “360° / CR” servo)	Discrete stepping with fixed angle per step; can rotate continuously through repeated stepping
Feedback	Built-in feedback on positioning servos (internal potentiometer + controller)	Usually open-loop (position estimated by counting steps); encoder optional for closed-loop feedback
Control Signal	Servo PWM signal (~50 Hz; pulse width determines angle or speed/direction for CR servos)	Step and direction pulses through a stepper driver; often includes current and microstepping settings
Positioning Accuracy	Good within limited travel	High repeatability of individual steps; long-move accuracy depends on avoiding missed steps
Driver Hardware	Integrated controller inside the servo; requires only power and PWM input	External driver required (e.g., DRV or TMC series driver boards)

Source: Cursor AI, March 2026

It was noted during the lecture that the key distinction between a stepper motor system and a servo system often lies in the presence of a feedback loop. Based on this consideration, the servo motor was selected for this stage of the project because it integrates position control internally and requires fewer external components - so it is more suitable for the rapid prototyping and initial experimentation.

Damping accessories of servo motor

Image of the installation of servo motor

The rubber grommets or bushings help isolate the servo from the mounting bracket. They absorb vibrations generated by the motor and gear train, reducing the amount transmitted to the surrounding frame. In addition, they help distribute the clamping force applied to the thin plastic mounting ears of the servo.

Basics on light direction sensor

Feature	Photoresistor (LDR)	Phototransistor	Photodiode
Operating Principle	Resistance changes with light intensity	Transistor activated by incident light	Diode generates photocurrent from light
Typical Output	Analog resistance change (usually via voltage divider + ADC)	Analog-like current or digital threshold switching	Small photocurrent or voltage
Response Speed	Relatively slow	Faster than LDR	Very fast
Circuit Complexity	Very simple	Moderate	More sensitive circuit design often required
Advantages	Cheap, simple, easy to interface	Faster response and better directional behavior	High precision and high-speed response

Source: Cursor AI, March 2026

The most cost-effective option would likely be the photoresistor (LDR). However, since a phototransistor was already available and purchased in Week 3, it is used for the current implementation. In future iterations, switching to a photoresistor could be considered as a potential optimisation if tighter budget constraints become relevant.

Week 5

Week 6

In almost every microcontroller project, resistors are doing one of a small set of jobs :

• Define a default logic level. Pull-up and pull-down resistors are especially important for ensuring stable startup behavior and preventing floating inputs, particularly when working with newer or less mature chips where internal default states may not yet be fully reliable
• Protect a pin
• Bias a sensor
• Limit LED current
• Control the input drive of a transistor or MOSFET

Value of ±5% is generally fine from the required value of resistor, but a few places like USB need known values to value like 5.1 kΩ.

Week 7

Week 8

Usage of capacitors

and different capacitors like ceramic and aluminum

Week 9

Topic	DS1307 / PCF8563	DS3231 Family
Oscillator Concept	Uses an external crystal whose frequency can drift with temperature changes	Integrates temperature compensation around an internal timing reference (TCXO-style approach) for improved stability
Typical Timekeeping Behavior	Can exhibit noticeable drift when environmental temperature changes	Maintains significantly more stable and accurate civil time over varying temperatures
Cost / Complexity	Lower cost and simpler implementation	Higher cost with additional internal compensation circuitry
Sleep / Backup Current	Often very low depending on crystal and board design	Still low in absolute terms, but not always lower than simple crystal RTCs; depends on operating voltage and IBAT characteristics

it is interesting that the oled work without rtc

Week 10

solar panel with back panel is 350 grams, motor is 50 grams

Week 11

Week 12

Week 13

Week 14

Week 15

Week 16

Week 17

Week 18

Week 19

Week 20

FPC connector

decide to use esp32devkit