> ## Documentation Index
> Fetch the complete documentation index at: https://docs.researchanddesire.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Sensor Specifications

> Technical limits and capabilities of the distance sensor

The Deepthroat Trainer uses an ultrasonic distance sensor to measure toy position in real-time. Understanding the sensor's capabilities and limits helps you get the most accurate training results.

## Sensor range

| Specification              | Value                              |
| -------------------------- | ---------------------------------- |
| **Maximum range**          | 22.5 cm (approximately 9 inches)   |
| **Dead zone**              | 1.7 cm (approximately 0.67 inches) |
| **Effective usable range** | 20.8 cm (approximately 8.2 inches) |
| **Minimum stroke length**  | 0.8 cm (approximately 0.3 inches)  |

<Info>
  The dead zone is the area closest to the sensor where it cannot accurately detect position changes. Objects within this zone may not register correctly.
</Info>

## How the sensor works

The distance sensor continuously samples your position and processes the data to provide smooth, accurate readings:

* **Sample rate**: 40 samples are averaged to reduce noise
* **Speed calculation**: Based on position changes over time
* **Direction detection**: Tracks whether you're moving toward or away from the sensor

<Note>
  The sensor uses a circular buffer of recent readings. Sudden, jerky movements may take a moment to register accurately as the buffer updates.
</Note>

## Position measurement

Positions are measured in centimeters from the sensor:

* **Start position**: Typically the "rest" position, further from the sensor
* **End position**: The target depth, closer to the sensor
* **Target window**: The acceptable range around the target position

For training accuracy, positions are clamped to valid ranges:

* Minimum detectable position: 1.7 cm (dead zone boundary)
* Maximum detectable position: 22.5 cm

## Calibration

Calibration captures two key positions:

1. **Minimum position**: The closest comfortable depth (100 samples averaged)
2. **Maximum position**: The rest/start position (100 samples averaged)

<Tip>
  For best results, hold steady during calibration. The trainer captures 100 samples at each position to ensure accurate measurements.
</Tip>

### Toy calibration vs device calibration

* **Device calibration**: Sets the overall sensor range for your setup
* **Toy calibration**: Stored in the cloud, remembers settings for specific toys

When using cloud calibration (Software 2.0+), calibration data is stored per-toy and synced across sessions.

## Limitations

### Dead zone

Objects within 1.7 cm of the sensor cannot be accurately measured. Training segments are automatically adjusted to respect this limit.

### Maximum range

The sensor cannot detect positions beyond 22.5 cm. If your setup requires longer distances, consider repositioning the trainer.

### Minimum stroke

Very small movements (less than 0.8 cm) may not register as separate strokes. This ensures the trainer doesn't count micro-movements as intentional actions.

### Environmental factors

<Warning>
  The sensor may be affected by:

  * Reflective surfaces near the sensing area
  * Very soft or sound-absorbing materials
  * Extreme temperatures
</Warning>

## Troubleshooting

<AccordionGroup>
  <Accordion title="Sensor readings seem inaccurate">
    * Recalibrate the device
    * Ensure the toy is properly positioned in the sensor's path
    * Check that nothing is obstructing the sensing area
  </Accordion>

  <Accordion title="Position jumps or stutters">
    * This may occur near the dead zone boundary
    * Try adjusting your segment parameters to avoid the extreme ranges
    * Ensure the toy moves smoothly without wobbling
  </Accordion>

  <Accordion title="Small movements aren't detected">
    Movements smaller than 0.8 cm may not register. This is by design to prevent false readings from vibration or minor adjustments.
  </Accordion>
</AccordionGroup>

## Related guides

<CardGroup cols={2}>
  <Card title="LED Feedback" icon="lightbulb" href="/dtt/technical/led-feedback">
    How LED colors indicate your position status.
  </Card>

  <Card title="Calibration" icon="sliders" href="/dtt/technical/calibration">
    Step-by-step guide to calibrating your trainer.
  </Card>
</CardGroup>