Using Arduino or ESP32 for TPMS 125kHz Signal Activation and Copying

Hello!

I was wondering in which section to give this post. However, considering that an Arduino or ESP32 type platform (due to its higher power) might be the ideal solution, I take the liberty to put the post here.

Well, TPMS tyre pressure sensor activators work in a simplified way in such a way that they send a signal on 125 kHz to the sensor activating it and, in some systems, it is more complex because it also determines the parameters of its operation (a kind of "programming" of the sensor, although it is not a typical program, but rather a certain sending of several or a dozen variables). We are talking about the activation itself (applying the activator to the tyre) and not the subsequent periodic sending of a signal about the current pressure and other parameters at 433 MHz.

I also suppose, but this is my guess, that in some systems it may not be a single signal, but an exchange of several messages between the sensor and the activator.

I'm wondering how one would go about making a signal copying circuit here that would capture the signal sent from the activator to the sensor, store it, and then be able to generate it itself. Ideally, it would not be a simple 'wav sound' recording of the signal, but rather something that analyses the recording structure and also allows, for example, the generation of another similar signal, e.g. with changed parameters.

Has anyone seen a similar project on the web somewhere? I've searched a bit, but either I'm looking poorly or they're not really there.

And if not, how would you go about doing something like this?

PS. Here are some sample activation devices if anyone is not familiar with the subject:
https://www.ateq-tpms.com/en-us/products/vt37/
https://autel.com/us/product/maxitpms-ts508/

@jarzabek666 Exactly not! A colleague flew on fast and threw in whatever he could find. I wasn't talking about capturing a 433 MHz signal and analysing it, I was talking about capturing and analysing a 125 kHz signal. This project, which you gave me, concerns the first thing (plus there is an option after Bluetooth) and additionally sensors, let's call it, alternative, where it is much easier to get technical data, while the "large" manufacturers hide what they can, as long as someone does not do them competition (I am not even talking about in the production of sensors, but in the device itself to activate).

What makes you think there is a signal on 125 kHz?

ken-wawa wrote:

125 kHz

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You have this frequency listed on the housing of the factory "programmer" for the sensors. This is RFID technology - as in proximity cards.

As far as I have found on the web, it is actually 125 kHz. There is only 433 MHz on the case, and I doubt there is activation at that frequency. RFID is either just 125 kHz or 13.56 MHz.

ken-wawa wrote:

As far as I have found on the web, it is actually 125 kHz. There is only 433 MHz on the case, and I doubt there is activation on that frequency. RFID is either just 125 kHz or 13.56 MHz.

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You can buy off-the-shelf RFID receivers for 125 kHz, only you would have to have a device to be able to eavesdrop on what it is sending and receiving.