he's just not interested in following the target rn.

Zumito

A small autonomous robot built on an ESP32, written in async Rust with Embassy. It has a custom 3D-printed chassis, a custom-designed gearbox, dual DC motors driven via MCPWM, and dual ultrasonic sensors (HC-SR04) for target tracking.

Hardware

• MCU: ESP32
• Motors: 2x DC motors controlled via ESP32 MCPWM peripheral, with H-bridge direction control
• Sensors: 2x HC-SR04 ultrasonic distance sensors
• Chassis: 3D-printed
• Gearbox: Custom-designed

Pin mapping

Function	GPIO
Motor 1 PWM	25
Motor 2 PWM	26
Motor 1 direction	27, 14
Motor 2 direction	12, 13
Ultrasonic 1 echo / trig	34 / 32
Ultrasonic 2 echo / trig	35 / 33
Status LED	2

Architecture

The firmware is fully async, using Embassy tasks for concurrency on a single-threaded executor:

• motor — PWM-based dual motor driver with direction control via GPIO H-bridge pins. Motors are controlled through Embassy signals.
• ultrasonic — Dual HC-SR04 sensor driver. Sensors are measured sequentially to avoid echo interference, with a configurable measure rate (10 Hz) and timeout based on max distance (4m).
• net — WiFi (STA mode via DHCP) and UDP receiver on port 8080. WiFi credentials are provided at compile time via SSID and PASSWORD env vars.
• control — Two control modes:
  • pusher: autonomous mode that uses dual ultrasonic readings to estimate target position via triangulation and drive toward it.
  • manual: remote control via UDP, receiving 3-byte motor speed commands from a network client.

There's also a companion web-based remote control app in zumito_remote_control/ (Axum + Askama).

Build and flash

Install Rust (via rustup) and the esp-rs toolchain (via espup).

Set WiFi credentials and flash:

SSID="your_ssid" PASSWORD="your_password" cargo run --release

TO-DO

• support motors using ESP32 MCPWM ✅
  • support dual motors ✅
  • support changing direction ✅
• add ultrasonic sensor support ✅
  • add dual sensor support ✅
• add manual control over wifi
  • connect to wifi ✅
  • define simple protocol via UDP for controlling motors
  • create client that will send UDP datagrams to device
• simplify codebase, remove bullshit
  • simplify motor module ✅
  • simplify ultrasonic module ✅
  • simplify net module

Resources

• Async Rust in Embedded Systems with Embassy - Dario Nieuwenhuis: excellent introduction to embassy and async flow in embedded systems
• esp-hal examples: took many ideas from here, the docs are really good also.
• Embassy Book: lots of info