Tag Archives: PIR

Microwave Motion Sensor

For detection of motion and direction of motion, the most common sensor was the Passive Infrared sensor or PIR. The presence of a human radiates infrared rays, and the sensor detects this along with variations in infrared rays to sense motion. Now, Infineon offers a fully integrated microwave motion sensor that includes antennas in the package along with built-in detectors for motion and its direction. The BGT60LTR11AIP, from Infineon, does not need an external microcontroller, as it has a built-in state machine to enable its operation. When operating in the autonomous mode, the sensor can detect the presence of a human being at a distance of 7 m at low power consumption.

To use the BGT60LTR11AIP, one does not need any know-how in Radio Frequencies, radar signal processing, or antenna design. Therefore, this sensor brings radar technology to all. Moreover, the small-sized radar unit has special features that provide a compelling cost-effective, and smart replacement for the traditional PIR sensors, providing low power operation for battery-powered applications.

The BGT60LTR11AIP microwave motion detector system makes the traditional motion-sensing applications smarter. For instance, the motion detector is useful in applications like screen-based systems (tablets, notebooks, TVs), automated door openers, security systems including IP cameras, smart lighting systems, smart appliances like kitchen appliances and vacuum cleaners, smart building appliances like proximity sensors, occupancy sensors, and contact-less switches, and smart home devices like smart speakers, smoke detectors, and thermostats.

Infineon has designed the BGT60LTR11AIP sensor as a low-power Doppler radar sensor working in the 60 GHz ISM-band. The tiny 3.3 x 6.7 x 0.56 mm package has a transmitter and a receiver antenna built into the package. It also has the built-in direction of motion detector along with a built-in motion detector. It can operate in multiple modes of operation, including a completely autonomous mode. The user can adjust performance parameters like detection sensitivity, frequency of operation, and hold time. The PCB design of the sensor uses FR-4 material.

In the autonomous mode, the BGT60LTR11AIP can detect up to a range of 7 m while consuming less than 2 mW of power. For this mode of operation, the BGT60LTR11AIP uses minimum external circuitry like crystal, LDO, along with some passive resistors and capacitors, and a shield.

The user can extend the flexibility of the BGT60LTR11AIP by adding an M0 MCU. This improves the detection range up to 10 m in SPI mode. The addition of an MCU offers advanced capabilities through configuration and signal processing via the SPI mode.

The user can incorporate the BGT60LTR11AIP sensor into systems to wake them up when required and put them to sleep or in auto-lock condition when it detects no motion for a specified time period. It has the capability to trigger additional functionality when it detects motion or senses a change in the direction of motion.

The BGT60LTR11AIP can thus add smart power-saving for many devices. Also, as microwaves can operate through non-metallic materials, the sensor can be placed out of sight in the end product. Therefore, the BGT60LTR11AIP sensor enables smooth integration of radar technologies in systems of daily use.

PIR Sensor: Let Raspberry Pi Guard your Home

With a versatile platform such as the Raspberry Pi or RBPi, prototyping a project is very simple. The scale does not matter for you can start with a single blinking LED and move on to complex quad copters. If you have the necessary components, simply add a little amount of imagination, and RBPi can work wonders for you.

A practical use for the RBPi is to sense the surrounding environment. Not only is this interesting, but also gathering this data is useful in myriad ways. For example, a weather station uses different sensors to measure pressure, humidity, wind speed and temperature. The main objective in recording and manipulating such data is to predict future weather conditions. Anyone technically savvy can store this data and manipulate it to produce tables and graphs for importing into other applications or projects.

Using a PIR or Passive Infra-Red sensor with an RBPi can be an effective guard for your home. These inexpensive sensors are used with motion activated air fresheners from which, you can easily harvest a couple for building this project. The PIR and RBPi combination can act as an effective burglar alarm in homes and offices.

The PIR sensor effectively sends out a beam of infrared light into the area that it is monitoring. As long as there is no movement in the area, the beam remains undisturbed. However, the slightest movement causes the beam to change, which the PIR sensor can sense. The PIR sensor, when connected to the RBPi, sends it a signal once it detects movement. The RBPi responds to this signal in a manner defined by its program.

For this project, the PIR sensor is set up to watch over an area for any movement. As soon as it detects movement, it triggers the RBPi, which responds by capturing a picture of the event on its camera, including recording a 10-second video at a resolution of 640 x 480 pixels.

Additionally, the RBPi will send out a text message to the owner’s phone, thereby alerting the user of an intruder or whatever that triggered the event. The text message includes the picture and the video. After sending the text, the RBPi will wait for 30 seconds before resuming its watchful stance.

Apart from being an effective burglar alarm, you can use this combination of PIR sensor and RBPi with its camera in many innovative ways. For example, those who like to study birds and their habitat, can set it up near the nest to record the coming and goings of the parent birds.

Using a text message to alert the user is effective, as all phones are capable of receiving SMS. Other methods using emails or tweets usually rely on 3G or Wi-Fi coverage and may not be always useable. Additionally, you can use several alerts from the project simultaneously. The RBPi stores the pictures and video it captures in its memory. You can retrieve them later via any means convenient.

To set up, install the OS in the RBPi, enable the camera via raspi-config and test its working. Use the command “raspistill -o test.jpg” for testing. This produces an image file by the name test.jpg.