16mm 40kHz Ultrasonic Transmitter and Receiver Pair

Specifications

• Frequency: 40 kHz (Resonant)
• Diameter: 16mm
• Component Type: 1x Transmitter (T), 1x Receiver (R)Casing
• Material: Durable Metal
• Lead Spacing: 0.28" (approx. 7.1mm) for easy perfboard or PCB mounting
• Height: 0.30" Height (approx. 7.6mm)
• Mounting Style: Through-hole (THT)

Applications 

• Custom Robotics: Build low-profile obstacle avoidance arrays tailored to your chassis.
• Fluid Level Measurement: Design custom tank-level sensors with specialized analog front-ends.
• Ultrasonic Anemometers: Measure wind speed and direction using time-of-flight between paired transducers.
• Security Systems: Create invisible volumetric motion detectors for room monitoring.

Unlock New Capabilities

• Past Projects: If you've mastered basic distance measurement using off-the-shelf HC-SR04 modules but found them too large or inflexible for your specific needs.
• The Upgrade: Moving to bare 16mm transducers unlocks the ability to design your own amplifier and driver circuits. You can boost the transmit voltage for longer range, or tune the receiver's op-amp gain for higher sensitivity in specific environments.
• Effort Level: Advanced. This requires a solid understanding of analog electronics. You will need a microcontroller to generate a 40kHz square wave, a driver circuit (like a MAX232 or push-pull transistors) for the transmitter, and a multi-stage operational amplifier (like an LM324) for the receiver.

Virtual Technician & Wiring Notes

• Identification: Check the back of the components. They are typically marked with a 'T' (Transmitter) and 'R' (Receiver). They are not interchangeable.
• Driving the Transmitter: Do not connect the transmitter directly to an Arduino/ESP32 GPIO pin. While it might emit a weak signal, you should use a driver circuit to swing the voltage higher (e.g., 10V to 20V peak-to-peak) for a strong acoustic ping.
• Amplifying the Receiver: The receiver outputs a microvolt-level AC signal. It MUST be passed through an active bandpass filter and amplification stage before a microcontroller can read the envelope.

Package Includes:

• 1 x 16mm 40kHz Ultrasonic Transmitter and Receiver Pair

Frequently Asked Questions (FAQ)

• What is the resonant frequency of these 16mm transducers?
  They are strictly tuned to operate at 40kHz for both transmitting and receiving.
• Are the transmitter and receiver identical?
  No, their internal piezoelectric crystals are tuned differently. One is optimized to generate sound (T), and the other to convert sound back to voltage (R).
• How can I identify the transmitter vs the receiver?
  Look at the bottom/back of the metal casing. They are usually laser etched or stamped with a 'T' and an 'R'.
• What is the operating voltage for the transmitter?
  While they can be driven by 5V logic via a driver, they are often driven up to 20V peak-to-peak using specialized circuits to achieve maximum range.
• Can I connect these directly to an Arduino or ESP32?
  No. The transmitter needs a driver to produce a strong enough pulse, and the receiver requires an op-amp circuit to amplify the tiny returned signal.
• What is the lead spacing for PCB mounting?
  The pins have a standard 0.28-inch (approx. 7.1mm) spacing.
• What are the physical dimensions of the casing?
  The casing is 16mm in diameter and 0.30 inches (7.6mm) high.
• Is the metal casing waterproof?
  No, this open-mesh metal face design is not waterproof. For wet environments, you need closed-face transducers like the JSN-SR04T.
• What IC is recommended to amplify the receiver signal?
  Standard quad op-amps like the LM324, TL074, or TLC274 are commonly used to build the multi-stage amplifiers required.
• How do I drive the 40kHz transmitter?
  Use your microcontroller's hardware timer to generate a precise 40kHz square wave, and feed it into a push-pull transistor pair or a MAX232 IC to drive the transducer.
• What is the maximum detection range I can achieve?
  The range depends entirely on your custom circuitry. A well-designed driver and high-gain receiver circuit can achieve 4 to 5 meters.
• Can I use these for ultrasonic cleaning?
  No. These are low-power acoustic transducers meant for air-based distance measurement, not high-power cavitation cleaning in liquids.
• Do these work well outdoors?
  They function outdoors but the open mesh makes them susceptible to moisture, and heavy wind can distort the 40kHz sound waves, reducing accuracy.
• What is the beam angle of these 16mm sensors?
  Bare 16mm transducers typically have a beam angle of around 60 to 80 degrees, though this can be modified by designing custom acoustic horns around them.
• Can I use multiple pairs in the same room?
  Yes, but they will interfere with each other if triggered at the exact same time. You must multiplex your pings in software.
• Why is my receiver not detecting the ping?
  Ensure your transmitter is outputting exactly 40kHz, check your op-amp gain stages, and make sure the T and R components are facing the same direction on an even plane.