Hodor hardware

HODOR - Highly flexible Open-source Door Operation Regulator

Overview

HODOR ("Holds your door") is a universal controller for sliding door motor systems. The device is designed to operate brushed DC motors ranging from 12 to 24V, providing a comprehensive control solution that can be configured via Wi-Fi for smart home integration.

The hardware design files were created in KiCAD 9.0.

System Architecture

The HODOR system consists of four main subsystems:

1. Controllerboard - Central processing unit based on the ESP32-S3
2. Power Supply - Handles voltage regulation and power distribution
3. Motor Control - Manages motor drive with H-bridge driver and feedback systems
4. Peripherals - Provides additional I/O and integration capabilities

Block Diagram

+---------------+    +----------------+
|    Power      |    |                |
|   Terminals   |----| Controllerboard|
|   12-24V      |    |   (ESP32-S3)   |<--->[SPI BUS]
+---------------+    |                |
                     |                |----+
                     +----------------+    |
                            ^              |
                            |              v
                            |        +----------------+
                            |        |  Peripherals   |
                            |        +----------------+
                            v
                     +----------------+
                     |  Motor Control |
                     |   H-Bridge     |
                     |   Encoder I/F  |
                     +----------------+

Technical Specifications

Subsystems

Controller Board (ESP32-S3)

The central controller is based on an ESP32-S3 microcontroller that handles:

• Motor control with PWM outputs
• Safety monitoring
• Encoder feedback processing
• SPI communication with peripherals
• Wi-Fi connectivity for configuration and smart home integration

The controller connects to both the motor control subsystem and peripheral I/O expansion modules through a combination of digital signals and an SPI bus.

Power Supply

The power subsystem converts the 12-24V input to the required voltages for the control circuits and provides:

• Input voltage sensing (V_BUS_SENSE)
• DC-link voltage monitoring (V_DC_SENSE)
• Protection circuitry

Motor Control

The motor control subsystem features:

• H-bridge driver with PWM inputs (DRV_PWM1, DRV_PWM2)
• Driver enable control (DRV_EN)
• Fault monitoring (DRV_~SF)
• Safety trigger and clear mechanisms (SAFETY_TRIG, SAFETY_~CLR)
• Current sensing (ADC_I_SENSE, ADC_DRV_FB)
• Quadrature encoder interface (ENCODER_A, ENCODER_B)
• An independet brake chopper, that burns voltage peaks above 27 V, to protect the driver IC.

The H-bridge allows bidirectional control of the DC motor with variable speed control via PWM.

Peripherals

The control device provides:

• Inputs (Potential free or 12..24 V DC)
• Status indicators
• Relay output

Key Features

• Supports brushed DC motors from 12 to 24V
• H-bridge driver with current sensing for motor protection
• Quadrature encoder interface for precise position feedback
• Configurable inputs
• Programmable relay output
• Wi-Fi connectivity for configuration and smart home integration
• Safety mechanisms for door operation
• Open-source hardware and software design

Applications

The HODOR controller is primarily designed for:

• Sliding door automation
• Other motor control applications with optional position feedback

Project Status

This project is currently in development.

Safety Features

HODOR incorporates several safety features:

• Current monitoring to detect obstructions
• Position feedback via quadrature encoder
• Hardware watchdog safety trigger
• Fault detection in the motor driver