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• Planning

  Ad • 11/05/2025 at 14:00 • 0 comments

  The Journey So Far

  This desktop robot began as an idea to combine sensors, movement, and personality into a palm-sized machine — one that could navigate its environment and display emotions through simple expressive cues.

  Core Platform: ESP32 Brain

  The robot’s main controller is an ESP32-WROOM-32, chosen for its dual-core performance, built-in Wi-Fi and Bluetooth, and flexible I/O support. Its processing power allows simultaneous control of motors, sensors, and display outputs — all while maintaining network connectivity for future OTA updates and data logging.

  The ESP32 handles:

  PWM motor control for precise movement

  I²C communication with all sensors and OLED displays

  Battery monitoring and power management

  Serial debugging and configuration

  Drive System: Two Wheels + Caster

  Mobility is achieved through a two-wheel differential drive system powered by N20 500RPM micro gear motors, providing a balance between torque and speed.
  Steering is accomplished by varying the speed of each motor — no servo steering is required.

  To stabilize the chassis, a single rear caster (ball-style) supports the frame, keeping the bot balanced while allowing smooth pivot turns.

  Power System

  The bot runs on a 3.7 V 2000 mAh Li-ion battery, offering solid runtime for its small form factor.
  A TP4056 USB-C charging and protection module manages charging and discharge safety. The power rail splits to feed:

  ESP32 logic (3.3 V regulated)

  Motor driver board (5 V or VIN depending on configuration)

  Sensor and display I²C bus (3.3 V)

  The goal is to later integrate automatic charging via magnetic pogo pins or a simple docking plate.

  Motor Driver

  A compact dual-channel PWM motor driver connects to the ESP32. Each motor is controlled via one PWM and one direction pin. This allows proportional speed control and smooth turning maneuvers.

  Sensors: Environmental Awareness

  The robot’s “eyes” are four VL53L0X Time-of-Flight sensors, placed strategically around the chassis:

  Front-left and front-right for collision avoidance

  Left and right sides for wall following and spatial mapping

  Rear or angled sensor (optional) for backing awareness

  Each sensor uses unique I²C addresses, set dynamically at startup to share the same bus.
  An accelerometer (connected via I²C) provides tilt detection and motion feedback — letting the bot understand its orientation or detect if it’s been lifted or knocked.

  Displays: Expression and Feedback

  Two 0.96″ OLED displays (128×64, I²C) are mounted at the front.

  Display 1: System data (battery level, IP, sensor readings, etc.)

  Display 2: Animated “eyes” — giving the bot a bit of personality

  Both displays share the same bus (address 0x3C), but a multiplexer or secondary I²C address can be used to differentiate them.

  Layout and Wiring

  Everything fits around a custom 3D-printed chassis, designed to roughly match the footprint of an Arduino Uno — compact but with layered sections for electronics and sensors.
  The current wiring includes:

  ESP32 GPIOs for both motor channels

  Shared I²C for OLEDs, ToF sensors, and accelerometer

  Power distribution from the TP4056 board

  Motor driver VIN from battery rail

  Battery sense pin for voltage monitoring

  Software and Control Logic

  Initial sketches handle:

  Basic motor testing (PWM forward/reverse)

  I²C detection of sensors and displays

  Data visualization on OLED

  Serial feedback for debugging

  The next software milestones include:

  Sensor fusion for obstacle detection

  Motion logic with avoidance behavior

  Display animations for idle/active states

  OTA update integration

  Wi-Fi dashboard for sensor readouts

  Chassis Design

  The chassis design is being modeled in Fusion 360, with considerations for:

  Two motor mounts with alignment brackets

  Rear caster housing

  Front plate for ToF sensors and OLEDs

  Detachable top shell for battery and board access

  Clean...

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