10mm Ultrasonic Sensor Transmitter and Receiver Pair (40kHz)

Specifications

• Component Type: Raw Ultrasonic Transducer Pair (1 Transmitter, 1 Receiver)
• Diameter: 10mm (Compact Form Factor)
• Center Frequency: 40.0 ± 1.0 kHz
• Bandwidth: 2.0 kHz (-6dB)
• Sound Pressure Level (Tx): ≥ 112dB (at 10Vrms, 30cm)
• Sensitivity (Rx): ≥ -70dB (at 40kHz)
• Capacitance: 2000pF ± 20%
• Housing Material: Aluminum (Open Type - Indoor Use)
• Directivity (Beam Angle): ~60° to 80°
• Operating Temperature: -20°C to +70°C

Applications

• Micro-Robotics: Ideal for "Sumo" or "Micro-Mouse" robots where every millimeter of frontal area counts.
• Custom PCB Integration: Embed distance sensing directly into your motherboard instead of using daughter boards.
• Liquid Level Sensing: Non-contact measurement for small tanks or dispensers.
• Object Detection: Invisible "tripwire" security systems.
• Gesture Control: Create short-range hand wave interfaces.

Project Evolution:

From Module User to Circuit Designer

• Prerequisites (The Past): You have likely mastered the HC-SR04 Module. You know how to use trigger and echo pins, but you are limited by the module's physical size and fixed gain.
• The Upgrade (This Product): The 10mm Transducer Pair unlocks Custom Acoustic Design. By building your own amplification and driving circuit (using Op-Amps like LM358 or specific driver ICs), you can adjust the gain, pulse width, and sensitivity to suit your specific environment.
• Effort Level: Advanced. Requires knowledge of analog electronics (Op-Amps, Signal Filtering).
• Minimum Hardware: You will need an oscillating circuit (to drive the Tx) and an amplifier circuit (to read the Rx).

Wiring & Safety Guide

Identification:

• T (Transmitter): Usually marked with a 'T' on the underside. This unit sends the pulse.
• R (Receiver): Marked with an 'R'. This unit listens for the echo.

 Warning: While the transducers can handle up to 20Vrms pulses for maximum range, most logic-level circuits drive them at 5V or 12V. Do not connect directly to a microcontroller pin without a driver transistor or buffer, as the current draw and capacitive load can damage the MCU.

 
Package Includes:
1 x Ultrasonic Transmitter (Tx) 10mm, 1 x Ultrasonic Receiver (Rx) 10mm

Frequently Asked Questions (FAQ)

• Can I connect these directly to Arduino pins like the HC-SR04?
  No, these are raw sensors. You need to build a driver circuit for the Transmitter and an amplifier circuit for the Receiver.
• What is the maximum range of these 10mm sensors?
  Range depends on your driving voltage and amplifier gain, but typically 20cm to 300cm is achievable with a good circuit.
• Are these sensors waterproof?
  No, these are "Open Type" sensors with a mesh front. They are for indoor use only and cannot be exposed to rain or water splashes.
• How do I tell the Transmitter and Receiver apart?
  Look at the underside of the sensor; they are stamped with a 'T' (Transmitter) and 'R' (Receiver).
• What voltage is needed to drive the transmitter?
  They work well with 5V to 12V square waves. Higher voltage (up to 20Vrms) produces a stronger signal and longer range.
• Why is the 10mm size better than the standard 16mm?
  The 10mm size is purely for compactness, allowing you to fit sensors into smaller enclosures where the 16mm version won't fit.
• Do I need a specific library to use these?
  Since you build the circuit, the code depends on your design. If you replicate the HC-SR04 logic, standard libraries like NewPing can still work.
• Can I use the HC-SR04 code with these sensors?
  Yes, if you build a circuit that provides a standard Trigger/Echo digital interface to your microcontroller.
• What is the beam angle of these sensors?
  They have a relatively wide beam angle of roughly 60 degrees, similar to standard ultrasonic sensors.
• Can I use these for liquid level measurement?
  Yes, as long as the sensor does not touch the liquid and condensation does not form on the mesh face.
• Do I need a matching transformer?
  For maximum power transfer, a tuning transformer is often used, but for simple circuits, direct driving with a MAX232 or transistor push-pull is sufficient.
• Why am I not getting any reading on my receiver?
  The raw signal is very weak (microvolts/millivolts). Ensure your Op-Amp circuit has sufficient gain (often 100x or more).
• Can I use two Transmitters to double the power?
  Yes, but they must be driven exactly in phase to avoid destructive interference.
• What is the minimum blind zone distance?
  This depends on how quickly your receiving circuit recovers from the transmission burst, usually around 2cm to 4cm.
• Are these compatible with Raspberry Pi?
  Yes, provided you build a 3.3V compatible interface circuit.
• Can I use the Receiver to listen to other 40kHz sources?
  Yes, the Receiver can detect any 40kHz ultrasonic sound, making it useful for beacon tracking.
• What happens if I swap the T and R units?
  The system will perform very poorly. Transmitters are optimized for output power, and Receivers for sensitivity.
• Can I paint the front of the sensor?
  No, painting the mesh will block the sound waves and ruin the sensor's performance.
• How do I mount these sensors?
  They fit into a standard 10mm hole. A small dab of hot glue or a friction fit works well.