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This section covers the electronics that connect your ESP32 controller to the motor driver. You can choose between the official OSSM PCB or build your own wiring configuration.

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Available Options

Official OSSM PCB

Purpose-built reference board with integrated level shifting and standardized connections for reliable operation.

DIY Wiring

Breadboard and custom wiring options for prototyping or using alternative motor drivers.

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Choosing Your Approach

The official OSSM PCB provides:
  • Pre-configured GPIO connections
  • Built-in 3.3V to 5V level shifting for reliable high-speed operation
  • JST connectors for clean cable management
  • Tested and validated design
The official PCB is recommended for most builders. It simplifies wiring, reduces assembly time, and eliminates common signal integrity issues.

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Key Considerations

Before selecting your approach, understand these critical factors:
Most ESP32 development boards operate at 3.3V logic levels, while many motor drivers expect 5V signals. Without proper level shifting, you may experience:
  • Missed steps at high speeds
  • Unreliable motor communication
  • Potential damage to components
Always verify the input voltage requirements of your specific motor driver before wiring.
High-speed step signals (up to 200 kHz) require clean wiring to prevent noise and signal degradation:
  • Keep step and direction wires as short as practical
  • Route signal wires away from motor power cables
  • Use twisted pairs or shielded cable for runs longer than 30 cm
Your motor driver requires a separate power supply sized for your motor:
  • Servo motors typically need 24-48V DC
  • Stepper motors vary by model (12-48V common)
  • The ESP32 runs from USB or a 5V supply independent of the motor power

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Specifications

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Power Input

ParameterValue
Voltage24V DC
Max current5A
Use a high-quality, UL-certified power supply. Low-quality supplies often cannot deliver their rated power and may cause damage to the motor or control board.

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Signal Outputs

ParameterSpecification
Signal typeStep-Dir
Logic level5V active low
ConnectorPH-4

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Motor Power Output

ParameterSpecification
Voltage24V
Max current6A
Terminals2× screw terminals
Wire gauge16–24 AWG

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Back-EMF Protection

The board includes built-in protection against regenerative voltage spikes:
  • Inline diode protects the power supply from reverse current
  • 1500µF capacitor absorbs regenerative energy up to 50V

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Next Steps

Board Design and Wiring

View detailed pinouts, connection diagrams, and wiring configurations for your specific motor driver setup.