Tire Pressure Sensors

Thread Starter

Rucks

Joined Mar 2, 2018
2
First of all, hi! I've scoured this forum for quite a while and am impressed by the abundance of knowledge here. And yes, I've done a search prior to posting this topic. While I did get some information, I still need a little bit more to fully understand.

I know that a standard TPM system consists of the following major components. • Sensor/Transmitter Device • RF Receiver Module • Low-Frequency (LF) Commander Device • Control Unit • Pressure Vessel (Tire).

Unless I'm mistaken, the RF receiver and the control unit are within/attached to the body of the car, whereas the pressure sensor/transmitter and the LF commander device are on a circuit board within an enclosed housing within the tire(s). I'm mostly concerned with the pressure sensor/transmitter and the LF commander device for my questions.

It is also my understanding that while cars broadcast at difference frequencies (315MHz vs 433MHz), they also must have a unique code that allows them to work with certain cars. For instance, a sensor for a Ford may not work with the receiver from a Chevy, even though both signals are broadcast at 315MHz. Is this information stored in the sensor/transmitter itself or is this another component on the board I am not aware of? Is there a way to change this code to allow me to use the sensor on a different brand of car (Ford vs Chevy)? And finally, if I wanted to custom make a pressure sensor, how can I program the sensor to work with one or the other?

I hope these questions make sense. Thanks.
 

WBahn

Joined Mar 31, 2012
29,875
The first thing you would need to do would be to understand the minutia of how the system works, including the details of the transmitted data formats and waveform details.

The LF commander is generally mounted in or near the wheel well so that only one tire's pressure sensor and transmitter is within range. That allows the system to adjust for tire rotations and such.

A good document to start with might be

http://ww1.microchip.com/downloads/en/AppNotes/00238b.pdf
 
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