Recently, many friends have sent messages saying they have received their desired offers, and I sincerely feel happy for you. You must believe that hard work will not be in vain.Looking at this year’s admission situation, device projects are one type of project that students applying for Interaction Design and Service Design majors are advised to do.So today, Teacher Cheng from Markpen Design Study Abroad continues to bring you knowledge related to Arduino, explaining the working principle and practical applications of the Arduino human infrared sensor.
The human infrared sensor should be familiar to everyone; it looks like a “white sphere” in the picture above. First, let me explain its working principle. The human body has a constant body temperature, generally around 37 degrees Celsius, so it emits infrared rays with a specific wavelength of about 10UM. The passive infrared probe works by detecting the infrared rays emitted by the human body at around 10UM. The infrared rays emitted by the human body are enhanced by a Fresnel lens and focused onto the infrared sensing element.The infrared sensing element typically uses a pyroelectric component. This component loses its charge balance when it detects a change in temperature due to human infrared radiation and releases charges outward. The subsequent circuit processes this signal to generate an alarm signal. Therefore, the basic concept of infrared detection is to sense the temperature difference between the moving object’s temperature and the background object’s temperature. This module generally serves as an input device in the Arduino circuit.
One complex aspect of this sensor is that some parts need to be adjusted manually. We can see that it has two orange buttons, which are used to adjust the sensing range and delay time. It can be adjusted to detect a range of 3 to 7 meters and a delay time from 5 seconds to 5 minutes. Let me explain the adjustment method: For the time delay adjustment, hold the Fresnel lens facing up, and the left knob adjusts the time delay; turning it clockwise increases the delay time, while turning it counterclockwise decreases the delay time. For distance adjustment, hold the Fresnel lens facing up, and the right knob adjusts the sensing distance; turning it clockwise decreases the distance, while turning it counterclockwise increases the distance.
The detection mode jumper adjustment is shown below. The three pins next to the knob are for selecting the detection mode. Insert the jumper cap on the top two pins for single detection mode; the bottom two pins are for continuous detection mode. Single detection mode: When the sensor detects movement, it outputs a high level, and after the delay time ends, the output automatically changes from high to low. Continuous detection mode: When the sensor detects movement, it keeps outputting a high level as long as the person continues to move within the detection range; it only delays changing the high level to low after the person leaves. The difference between the two detection modes lies in whether the high level output continues when the person keeps moving after triggering the detection.
As for the application of the human infrared sensor, there are several common experiments we can try ourselves. First, we can make an alarm system. We can use the human infrared sensor as an input device to trigger a buzzer, which is the output device. Secondly, there is the human sensing light, which connects the light as the output device in the entire circuit. When connecting the circuit, we must pay attention to adjusting the two aspects mentioned above: delay time and sensing distance. This sensor also has a mini version, and everyone can choose a suitable sensor for experiments based on their own situation.Today’s explanation of Arduino knowledge ends here. Interested friends can buy materials and try some experiments at home. The New Year is approaching, and I hope everyone can have a peaceful and healthy New Year at home. At the same time, friends preparing to go abroad should also plan their time well and manage their time effectively.All images are sourced from the internet.
Article Author:Cheng Yaqiu
Master of Product Design, Royal College of Art, UK
Specializes in product service system design, user experience design, and hardware Arduino interaction.
Any questions about schools and portfolios are welcome for communication at any time.
