When we are driving a car, some ideas may bring up in our mind. Like, if my tires are broken, how do we deal with it? How to monitor my tire working conditions? Does my car have a system to alarm or monitor the tires' condition? Don't worry, RF-star can help you to learn the Tire Pressure Monitoring System (TPMS) and then we can explore the application and advantages of using the RF-star CC2340 Bluetooth Low Energy(BLE) module in TPMS.

Firstly, let's hush out the definition and the mode of TPMS.

What is TPMS?

A TPMS is a mandatory feature that monitors the air pressure in a vehicle's tires. It provides real-time information to the driver, ensuring optimal driving conditions and reducing the risk of accidents.

There are two TPMS modes --- indirect and direct. Firstly, let's see the indirect TPMS, also called WSB (Wheel-Speed Based) TPMS. This kind of system is using the wheel speed sensor of the vehicle to compare the speed difference between the tires to achieve tire pressure monitoring. If the tire pressure decreases, the tire diameter will become smaller than usual, which will cause the vehicle speed to change.

Then, let's see the direct TPMS. We also call it PSB (Pressure-Sensor Based) TPMS. That is, the pressure sensor is installed in each tire directly to measure the air pressure. And we need a wireless transmitter to send pressure information to a central receiver system (vehicle center control panel or external receiver panel)and then display the tire pressure data to drivers. When the tire pressure is too low or leaks, the system will automatically alarm.

Figure1 PSB (Pressure-Sensor Based) TPMS

What Wireless Technology Is Using in TPMS?

As mentioned above, PSB TPMS needs the wireless transceiver. RF-star and most of the other TPMS solution suppliers usually recommend BLUETOOTH LOW ENERGY(BLE) technology taking into consideration the low costs and the high RF performance.

Figure2 Advantage of BLE technology

PSB TPMS has two installation modes --- the built-in type (inside of the tire) and the external type (fixed on the tire valve). Both modes have high requirements for Radio Frequency (short for RF).

Which BLE Modules Does RF-star Recommend?

RF-star released a wide series of BLE modules based on Texas Instruments CC2340Rx. The friendly design and high-quality performance make those wireless modules popular for automotive applications.

Different IC package is with different module dimensions. BLE modules RF-BM-2340B1 and RF-BM-2340B1I are based on CC2340R5 5*5 IC, and 24 GPIOs are lead out. RF-BM-2340A2 and RF-BM-2340A2I are using CC2340R5 4*4 IC, all 12 GPIOS are available. Each series has the high-performance PCB antenna version and IPEX connector version for feasible external antenna, that can meet different size and transmission range requirements. 8mm*8mm is the smallest one in the RF-star CC2340 BLE module series, that is RF-BM-2340C2.

Figure3 CC2340 modules with different dimensions

The BLE modules with CC2340 chipset have an industry-leading standby current of less than 710 nA, which is 40% lower than competing devices. And if you are using them in TPMS applications, more than a 10-year coin battery life with excellent power management reduces maintenance and replacement costs.

Figure4 Features of RF-BM-2340B1 BLE module

In the following step, a new CC2340 SoC will be released by TI, which supports an industrial temperature range of -40ºC to 125ºC, with AEC-Q100 certification. RF-star will follow the step and release its own CC2340 Bluetooth LE module for automobiles. Thus, no matter the vehicle pre-assembly and after-assembly TPMS markets, RF-star can meet your requirements to support you work well in the Internet of Vehicles (IoV).

Figure5 Prospect of coming to CC2340 SoC

After you have the advantages of the newest CC2340 BLE modules in mind, it’s your turn to explore TPMS working theory by taking CC2340 modules for example.

How Does the BLE Module Work in TPMS?

When we embed the CC2340 BLE modules into a TPMS, how will the system work? Let's see the whole block diagram first.

Figure6 The block diagram shows how BLE module work in TPMS

After the power supply is supported by the center control panel or the external receiver panel, the TPMS will start to work. The MCU 1 will send the command to the CC2340 master module to ask for the CC2340 slave module with sensor data in real-time. Then the TPMS is totally working during driving.

When any tire has high tire pressure or air leakage, the TPMS with BLE technology can raise the alarm on the screen and direct the location of the exact tire.

So, Bluetooth LE TPMS solution helps improve vehicle safety, performance, and the driving experience. Of course, if you think adding four MCUs on the tire end is not cost-effective, you can choose to regard the module as the MCU, the resources and GPIO numbers are quite enough and easy for development.

Conclusion

Figure7 Why are CC2340 BLE modules outstanding in TPMS

To sum up, the CC2340 Bluetooth module plays a vital role in enhancing the convenience and highly real-time of TPMS in modern vehicles. Its efficient wireless communication, low power consumption, and tiny design make it an ideal choice for automotive manufacturers.

With TPMS embedded the CC2340 module, drivers can have peace of mind, knowing that their tires are constantly monitored for optimal performance and safety.

If you’d like to learn it visually, go to RF-star video library.

For more information or CC2340 samples, see www.rfstariot.com or contact us at info@szrfstar.com.