Use of Sub-1GHz wireless technology using radio frequencies

A motion detector is a device that detects and notifies the presence of a person in a designated area. It is used in homes, office buildings, and other facilities. The detector can transmit sound, light, or wired/wireless notifications to various devices, such as control panels, alarms, and cloud systems.

Wireless motion detectors are easy to install and expand because they do not require wiring through walls. Common detection techniques include PIR (passive infrared), ultrasonic emitters, and microwave emitters.

Wireless motion detectors, installed indoors or outdoors and primarily used as intrusion detection systems, generally utilize Sub-1GHz wireless technology due to their excellent radio frequency (RF) performance and low power consumption and cost.

TI’s System-on-Chip (SoC) Sub-1GHz solution (CC13x0 wireless MCU) integrates a low-power, feature-rich MCU and RF solution into a single chip. In a sensor system (Figure 1), this low-power wireless MCU can operate as the system’s main MCU, directly interfacing with the sensor or through amplifiers, filters, and comparators. Additionally, the CC1350 and CC1310 wireless MCUs integrate I2C, UART, and SPI for peripheral control, and also have a built-in 12-bit analog-to-digital converter (ADC) for analog signal sampling.

By using an SoC wireless MCU instead of a separate MCU and RF transceiver, functional integration can be increased while reducing size and cost. The main MCU provides sufficient flash and RAM for ARM® Cortex®-M3 architecture-based applications and protocols.

This MCU product provides the foundation for low-power designs with very low shutdown or standby currents (0.185A and 0.7A, respectively), 51A/MHz MIPS (million-instruction-per-second) consumption, and receiver (5.4mA) and transmitter (13.4mA at 10dBm) currents. Additionally, by introducing an innovative low-power execution unit called a sensor controller module, the rest of the system (the main MCU) can enter sleep mode while monitoring sensors. Consequently, the system consumes only 0.95A even while performing ADC readings every second.

In a typical motion detector system, the sensor controller continuously monitors the sensor. As shown in the figure below, when triggering occurs, the controller activates the main MCU, and the main MCU notifies the central unit.

The SimpleLink Sub-1GHz CC13x0 Software Development Kit (SDK) provides two easy options for RF communication. The first option is Easylink, a proprietary RF interface utilizing a standard-based 802.15.4g stack for one of the supported modulation schemes and star topologies. Easylink allows you to add motion detectors to existing wireless systems using your own proprietary protocol. However, if you do not have a proprietary protocol, using TI's 15.4g stack is more suitable. This stack includes standard access mechanisms such as acknowledgment, security features, and frequency hopping options. This tool can be used to protect systems from RF jamming, cyberattacks, and noisy environments. TI also provides end-to-end sensor-to-cloud solutions that enable two types of communication between sensor nodes and cloud operators for monitoring and control.

The CC1350 wireless MCU supports both Sub-1GHz and Bluetooth Low Energy connectivity. The addition of Bluetooth Low Energy connectivity solutions enables the development of new advanced applications. Bluetooth Low Energy technology allows for the easy addition of user interfaces to motion detector systems (at minimal cost), enabling end users to communicate directly with individual smart devices to configure settings and obtain information from the entire system. Figure 3 shows multiple motion detectors installed inside a house. These sensors all form a Sub-1GHz network, allowing them to connect alarm sirens to one another. Furthermore, since these devices utilize Bluetooth Low Energy connectivity, they can be accessed via smartphones or tablets.

To set up this system, connect a mobile phone or tablet to the motion detector via Bluetooth Low Energy and transmit the network attributes and security secrets of the Sub-1GHz network. Once the network configuration is complete, the motion detector switches to Sub-1GHz mode and connects. You can configure motion sensor-related settings, such as detection mode, sensitivity, and day-of-the-week mode, using the mobile phone or tablet interface. In addition, you can easily test the system by using a mobile phone to check the network status without having to wait for an alarm to sound.

In addition, connecting to a mobile application via Bluetooth Low Energy allows you to easily push software updates from any part of the system, ensuring you always maintain the latest version and fix bugs. You can notify users of updates, push them to mobile app users, and inform them to upgrade the system.