US-100 Ultrasonic Sensor from Adafruit
If you are looking to incorporate an ultrasonic sensor in a project to precisely measure distance, the US-100 sensor from Adafruit is a fantastic option. It is a reliable and versatile sensor that is also cost-friendly since you can buy them for less than $10. The US-100 Ultrasonic sensor from Adafruit is an easy-to-use sensor that can provide reliable, short to mid-range distance measurements, making it ideal for applications where precise detection of objects within a limited range is required.
This sensor is very similar to the HC-SR04 but there are some added features for more flexibility. The US-100 sensor is capable of UART where the HC-SR04 is not. It also has an extra GND pin for added connection versatility. Another feature about the US-100 is that it can operate from 2.4~5.5VDC so there is no need for any logic level shifters or dividers. Whatever power your microcontroller provides should suffice for this sensor.
Specifications
When selecting and integrating an ultrasonic sensor into your project, it’s essential to not only consider basic specifications of the sensor but also environmental factors. These additional considerations will help you choose the right sensor for your application and ensure optimal functionality in your project.
Range – | 2cm – 450cm (.079” – 177.17”) |
The range is the distance in which the sensor can accurately detect the presence of an object and measure the distance. This will be crucial in determining which distance sensor will fit your project. The range of the 4019 sensor is 2cm – 450cm with the best accuracy between 10cm – 250cm.
Accuracy – | .3cm, + 1% |
The Accuracy refers to how close the sensor’s measurement is compared to the actual distance of the object being detected. The 4019 sensor has a baseline accuracy of .3 cm and a percentage accuracy of ±1%. This means that at close distances, the sensor’s readings can be off by up to ±.3cm, for reach measured distance of 1 meter, the reading by vary by an additional ±1cm.
Beam Angle – | < 15° |
Sound waves are emitted from a ultrasonic sensor in a cone-shaped pattern. The angle of this cone is called the beam angle and refers to the area within which the sensor can detect an object. The 4019 has a beam angle of < 15°.
Operating Temp – | -20°F to +70°F |
Operating temperature refers to the range of ambient temperatures within which the sensor is designed to function effectively. Temperature variations can have an impact on the performance of the sensor because the speed of sound increases with temperature.
Power – | 2.4VDC - 5.5VDC @ 2mA |
This is the power that the sensor needs to properly operate. The 4019 sensor power requirement is 2.4V – 5.5V which offers a wider range than the traditional 3.3V-5.0V for more flexibility.
Dimensions – | 45mm(W) x 20mm(H) x 15mm(D) |
Weight – | 9g |
When choosing the correct ultrasonic sensor for your application, it’s important to go beyond the basic specifications and consider additional factors that could impact performance. Certain things should be considered such as the conditions of the application: Is there extreme temperature variations or any presence of obstacles or is there any concern of moisture or dust that would require specific protective features. The mounting style is another aspect to consider as it influences how and where the sensor can be installed.
Pinout
- VCC – Power supply, this can be from 2.4~5.5VDC. No logic level shifters/dividers needed.
- TRIG/TX – Responsible for initiating process of emitting ultrasonic waves.
- ECHO/RX – Responsible measuring pulse width of sound waves.
- GND – Ground Pin/Additional Ground pin for flexibility
- GND – Ground Pin/Additional Ground pin for flexibility
There is a jumper on the back of the sensor that allows you to switch between HC-SR04 mode and UART. When the jumper is removed, it acts like an HC-SR04 (Trig and Echo). When the jumper is in place, the sensor is in UART (Tx and Rx) mode.
How It works
Ultrasonic sensors use sonar to determine the distance between the sensor and an object by emitting high-frequency sound waves and listening for their echoes. The time it takes for the sound wave to travel to the object and back is directly related to the distance of the object. This time delay can be calculated to accurately measure distance and detect the presence of physical objects within its range.
Here is a step-by-step process of how an ultrasonic sensor works:
- The ultrasonic transmitter (initiated by the Trig Pin) emits a high-frequency sound wave (about 40kHz)
- The sound wave travels through the air until it hits an object (within range) and bounces back to the sensor
- When the sound wave returns to the sensor, the receiver (initiated by the Echo Pin) measures the pulse width of the sound wave, which is used to determine the distance of the object.
HC-SR04 & UART Modes
-HC-SR04 mode is compatible with Arduino, CircuitPython, or MakerCode.
-UART mode is compatible with Arduino, CircuitPython. This mode allows you to send a 0x55 command to receive 2-byte value (16-bit) representing distance in mm. If you send 0x50 to read temperature in degrees Celsius. This is helpful if you don’t have a USB-serial converter or the special timing needed for the Trig/Echo of the HC-SR04.
Example Code
Click HERE to get free example code from GITHUB to work with the US-100 sensor, both UART and HC-SR04 are included.
Conclusion
The US-100 Ultrasonic Sensor from Adafruit is a versatile and user-friendly sensor that is ideal for various distance measurement projects. It provides significant advantages over similar sensors like the HC-SR04 with it’s compatibility with both HC-SR04 and UART and added flexibility in pin connections. By carefully considering both the sensor’s specifications and the specific environmental conditions of your project, you can ensure that the US-100 will be a great choice for your application.