robodatech.1 · Calibrate
Measure known targets at several distances. Record bias and repeatability; mount the sensor rigidly and repeat the test after moving it.
Sensors
Help your robot understand its surroundings.
Distance, motion, position, and vision sensors turn physical events into useful measurements. Learn what each can tell you—and what it cannot.
Try it yourselfChange an input.
Change an input.
See what follows.
A simplified learning model. Values describe the model, not a connected robot.
A sensor reading is a measurement with uncertainty.
Every reading has units, a timestamp, a useful operating range, and possible errors. Before using it to command motion, check whether it is valid and fresh. A missing ultrasonic echo is an unknown distance, not proof of an empty path. Filtering can reduce noise, but adds delay; a smooth old reading can be less useful than a noisy fresh one.
Choose by the quantity you need
| Sensor | Measures | Application | Limitation |
|---|---|---|---|
| Ultrasonic | Sound travel time | Low-cost obstacle distance | Angled or soft surfaces may lose the echo. Temperature changes sound speed. |
| Multizone ToF: VL53L8CX | Optical distance in up to 8 × 8 zones | Near-field obstacle maps and occupancy | Read status and confidence; ambient light, cover glass, and targets affect useful range. |
| IMU: BMI270 example | Acceleration and angular rate | Tilt estimation and short-term motion tracking | Gyro bias drifts when integrated. Acceleration contains gravity and motion. |
| Wheel encoder | Shaft increments and direction | Speed feedback and odometry | Wheel slip changes real travel without changing encoder counts. |
| Camera | Image intensity and color | Inspection and visual landmarks | Lighting, calibration, processing delay, and privacy matter. |
Read an 8 × 8 depth sensor
The VL53L8CX provides multiple distance zones rather than a conventional image. Transform zone directions into your robot frame, reject invalid zones, and group nearby returns. Do not interpret every low-confidence cell as a free path.
Build a trustworthy measurement pipeline
2 · Validate
Store value, units, timestamp, and quality together. Reject impossible jumps and stale samples before passing them to the motion controller.
3 · Combine
Use wheel encoders for fast local motion and another sensor for correction. Correlated measurements can share the same error; more sensors do not automatically mean better estimates.
Try a distance experiment
At approximately 20°C, use a sound speed of 343 m/s. A 40 cm target produces a round trip of about 2,332 µs. The simulation divides round-trip time by two. Compare a flat board with fabric and an angled surface, and record failed readings instead of replacing them with zero.
For an HC-SR04, check the exact module requirements. Its usual 5 V echo output needs appropriate level shifting before a 3.3 V GPIO.
Go to the source
Manufacturer and project documentation. Reviewed 20 September 2026; check your exact board revision and software release.