ucsd-creative-robotics

Week 2 - Making Things Move

Agenda

• Review/Discuss HW1 + Reading
• Artist(s) of the Day
• Tutorial: PWM and Analog Output
  • Analog output
• Tutorial: Making things Move
  • Servo sweep
  • Servo knob
  • Photoresistor Part 2 light responsive motion
• Homework
  • HW2 Making Things Move (DUE next Tuesday 10/20)
  • Project 1 - Augmentation (DUE Week 5)

Artist(s) of the Day

Daniel Rozin

• Wooden Mirror
  • Thousands of servo motors
• Longer video from Wired (2019): https://www.youtube.com/watch?v=kV8v2GKC8WA
• Wooden Mirror (2000) in SIGGRAPH Archives: https://digitalartarchive.siggraph.org/artwork/daniel-rozin-wooden-mirror/
• Danny Rozin portfolio

Analog Input and Output

Analog Output

Commonly called PWM (Pulse Width Modulation).

https://www.arduino.cc/en/Tutorial/BuiltInExamples/Fade

• NOTE: this is a very similar circuit and wiring as Digital Output above.
  • the difference is that here we are using analogWrite() (reference)
  • and a different pin (one of the PWM capable pins)
• Demo:
  • Show the “duty cycle” on the oscilloscope.
  • Show how a different analog output corresponds to (1) a waveform and (2) a different measured voltage.
• TODO:
  • modify the speed at which it fades. (hint: change the delay(). see the delay reference)

Making Things Move

Another use of Pulse Width Modulation is driving the position of a servo motor.

Servo Sweep

1. Install the ESP32Servo library:
   • Tools -> Manage Libraries:
     • 
   • Search for ESP32Servo. Click Install:
   • 
2. Under Examples -> ESP32Servo, select the Sweep example:
   • 
   • Make sure that your servo is connected to the pins used in the example code. Or change the pins in the code to match your setup.
   • 
3. Wire up the servo:
   • BLACK/BROWN -> Ground
   • RED/YELLOW -> +5V
   • ORANGE -> your servoPin.
4. Compile and run the example.

What is PWM?

Timing Diagram

Simplified Wiring Diagram

https://www.arduino.cc/en/Tutorial/LibraryExamples/Sweep

Talk Through

• How to read a schematic
• Pulse Width Modulation
  • (analogWrite()!)
  • more on PWM Secrets of Arduino PWM

Servo Knob

We are going to use the potentiometer knob as an input device. You can think of a knob as a kind of simple “sensor” to drive the servo motion.

• Under Examples -> ESP32Servo, select the Knob example:
  • 

• Reading the schematic.
• Use the knob to control the servo.

Homework

• Exercise 2: Making Things Move DUE next Tuesday 1/20
• Start ideating for Project 1 Augmentation

References

• Sparkfun Tutorial on Pulse Width Modulation