Battery-free TPMS

Dtank wrote:

GordonThree wrote:


There's no sensor inside the wheel. Computer uses voodoo....... My guess

Same voodoo a Thermos uses.

Keeps hot things hot, cold things cold. - How do it know ??

Voodoo, of course !!...:S

.

The ABS Sensors sense how fast the wheels are turning, essencally tacs'.. If all wheels are PROPERLLY inflated then tehy all have the same radius and (And diamater) and all turn at the same speed.

If one is low the tire gets effectively "Smaller" and turns faster.

The computer sees this and reports. No voodo involved, simple mathmatics and physics Only "Voodo" to those who deny science.

Keeps hot things hot, cold things cold. Does that mean I can put in a cup of coffee and a popsicle?

GordonThree wrote:


There's no sensor inside the wheel. Computer uses voodoo....... My guess

Same voodoo a Thermos uses.

Keeps hot things hot, cold things cold. - How do it know ??

Voodoo, of course !!...:S

.

Pressurepro is the only US made system I would consider.

I saw a couple of posts saying that the indirect TPMS is no longer used. It is being used in some or all current Audi and Honda models.

And personal jet packs are probably in the future too, but sometimes simple works very well. A small battery that last a couple years versus the rather convoluted query/response type necessary for the SAW system to work. KISS.

Remember this when you were a child?




If there were innovators that were not willing to think outside of the box as many on this forum seem not willing to do we would not have the Apple watch and cell phones.

A batteryless TPMS sensor or one that can be recharged due to wheel motion is probably in the future.

Think about it. The force on a valve stem while the wheel is in motion is not constant. There is still gravity acting on the valve stem which explains why rubber valve stems do not work well with external TPMS sensors.

did some research and yes, some SAW device sensors are coming to market. they don't need a battery, but the sensor must be located quite close to the transmitter, within a few feet or less. so, they mount a transmitter near each tire to interogate the wheel. for aftermarket that means installing sensors in the wheels and then installing transmitters near each wheel and that transmitter then either wired or wireless to the display.

most talk about using CANbus, probably aimed at OEM mfg applications.

the do appear to offer faster response times and faster update rates.

Harvey51 wrote:
Hmm, why not a sensor mounted in the rim, powered by electromagnetic induction as new phones can be charged?

Induction requires very close proximity or high power.

GordonThree wrote:
There's no sensor inside the wheel. Computer uses voodoo or maybe math, ambient temperature and wheel speed to calculate air pressure. My guess

Other manufacturers tried this long time ago and found it to be not accurate enough. It also does not handle the case of all tires equally under or over inflation.