Choose a sensor based on what your project needs to measure: distance, object detection or light.
Different modules produce different signals. Confirm voltage and output type from the documentation for your exact module.
Uses an ultrasonic pulse and measures its return time to estimate distance. Best for many non-contact distance projects where the target can reflect sound.
Check: trigger and echo wiring, timing, target angle and the sensor's voltage requirements.
Read the HC-SR04 guide →Many reflective IR modules detect changes in reflected infrared light. Actual range and output behavior depend on the module and surface.
Check: indicator LEDs, sensitivity adjustment, ambient light and sensor height.
Read the IR sensor guide →An LDR changes resistance as light levels change. A voltage divider can turn that resistance change into a measurable analog voltage.
Check: resistor value, analog input wiring and the room's lighting when calibrating.
Learn about LDR sensors →Explore project ideas after you understand the readings, mounting and limitations of distance sensing.
Explore ultrasonic projects →Build five beginner projects using reflective IR modules, with testing and troubleshooting advice.
Explore IR sensor projects →Work through these checks before changing several parts of a circuit at once.
Check the module's rated supply voltage, verify polarity, and ensure sensor and controller grounds are connected when required.
Use a small sketch or simple meter measurement to confirm the module changes output as the target or light level changes.
Target material, angle, sunlight, nearby objects and electrical noise can all affect readings. Test under the conditions where the project will run.