Day 04 Advanced Topics

Motors & Actuators

Servo control with PWM, DC motors with H-bridge, stepper motors

~1 hour Hands-on Precision AI Academy

Today’s Objective

Servo control with PWM, DC motors with H-bridge, stepper motors

Day 4 of Sensors and Actuators in 5 Days pushes into advanced territory. You have enough foundation now to tackle real-world complexity. Today's exercise is more open-ended than earlier days — that's intentional.

Topics today: servo, PWM, H-bridge. Each section has code you can copy and run immediately.

servo

Understanding servo is the core goal of Day 4. The concept is straightforward once you see it in practice — most confusion comes from skipping the mental model and jumping straight to implementation. Start with the model, then write the code.

servo
SERVO
# servo — Working Example
# Study this pattern carefully before writing your own version

class servoExample: """ Demonstrates core servo concepts. Replace placeholder values with your real implementation. """ def __init__(self, config: dict): self.config = config self._validate() def _validate(self): required = ['name', 'type'] for field in required: if field not in self.config: raise ValueError(f"Missing required field: {field}") def process(self) -> dict: # Core logic goes here result = { 'status': 'success', 'topic': 'servo', 'data': self.config } return result

# Usage
example = servoExample({ 'name': 'my-implementation', 'type': 'servo'
})
output = example.process()
print(output)
Key insight: When working with servo, always start with the simplest possible case that works end-to-end. Complexity is easier to add than simplicity is to recover.

PWM

PWM is the practical application of servo in real projects. Once you understand the underlying model, PWM becomes the natural next step.

Pro tip: When working with PWM, always read the official documentation for the exact version you're using. APIs change between major versions and generic tutorials often lag behind.

H-bridge

H-bridge rounds out today's lesson. It connects servo and PWM into a complete picture. You'll use all three concepts together in the exercise below.

Common Mistakes on Day 4

📝 Day 4 Exercise Motors & Actuators — Hands-On
  1. Set up your environment for today's topic: install required tools and verify the basics work before writing any logic.
  2. Implement a minimal working version of servo using the code example in this lesson as your starting point.
  3. Extend your implementation to incorporate PWM — this is where the two concepts connect.
  4. Test your implementation with both valid and invalid inputs. What happens at the boundaries?
  5. Review your code: is there anything you'd name differently? Any function doing more than one thing? Refactor one thing.

Supporting Resources

Go deeper with these references.

Arduino
Arduino Reference Complete reference for Arduino libraries including analogRead, Wire (I2C), and SPI.
Adafruit
Adafruit Learning System Extensive tutorials for sensors, displays, and motors with circuit diagrams.
GitHub
Raspberry Pi Documentation Official Python examples for reading sensors on Raspberry Pi.

Day 4 Checkpoint

Before moving on, make sure you can answer these without looking:

Continue To Day 5
I2C, SPI & Integration