Power Requirement of Sensors

Introduction

Sensors in robots require electrical power to operate, and their power requirements vary depending on type, complexity, and operating frequency. Proper planning of sensor power is essential to ensure reliable operation, prevent system failure, and maintain efficiency in robotic platforms.

Common Sensor Power Ratings

Here are typical power supply requirements for common sensors:

  • IMU: 3.3V or 5V, low current (~10–50 mA)
  • GPS: 3.3V or 5V, medium current (~50–100 mA)
  • LiDAR: 5V or 12V, high current (up to 1–2 A for 3D models)
  • Camera: 5V USB or dedicated power, moderate to high current
  • Ultrasonic Sensor: 5V, very low current (~15 mA)

Key Considerations

1. Voltage Compatibility

Sensors often require specific voltage levels (e.g., 3.3V, 5V, or 12V). Supplying incorrect voltage can damage the sensor. Always check the datasheet and use voltage regulators or level shifters if necessary.

2. Current Availability

Ensure your power supply can provide enough current for all sensors simultaneously. For instance, multiple LiDARs and cameras on a mobile robot may exceed the limits of USB ports or small battery packs.

3. Noise and Interference

Power supply noise can interfere with sensitive sensors like IMUs or analog distance sensors. Use filtering capacitors, proper grounding, and isolated power lines for noisy components like motors.

4. Power Budgeting

During system design, create a power budget by calculating total consumption across all sensors and components. This helps in choosing appropriate batteries or power converters.

5. Protection Mechanisms

Use fuses, over-voltage protection, and reverse polarity protection to safeguard expensive sensors.

6. Startup and Inrush Current

Some sensors, especially LiDARs and cameras, draw higher current during startup. Plan for inrush protection and staggered boot-up if needed.

Power Supply Types in Robotics

  • Battery Packs: Often used in mobile robots. Choose Li-Ion or LiPo based on voltage and capacity needs.
  • Regulated Power Modules: Step-down (buck) or step-up (boost) converters to match sensor voltage.
  • USB Power: Common for low-power devices and cameras.
  • PoE (Power over Ethernet): Used for powering IP cameras and some advanced sensors.

Real-World Examples

  • Using a UBEC to power 5V sensors from a 12V drone battery
  • Deploying an Ouster LiDAR with a dedicated 12V 3A DC supply
  • Running multiple sensors from a Raspberry Pi with powered USB hubs

Conclusion

Managing power requirements for sensors is a critical aspect of robotic system design. Ensuring proper voltage levels, sufficient current supply, and clean power helps achieve reliable and efficient operation. A careful power plan not only protects components but also extends system runtime and performance.