USA TPMS Frequency

[trophied]

I have a set of spares so I put fresh batteries in a set of spares and get them installed when I get tires installed.  Probably at least 2 or 3 times as often as necessary to keep them operational, but at least I never see the warning for the sensors.  Another one of those Trophy periodic maintenance things.

[STJIM]

Thanks for that chip info.

I found the data sheet :  https://www.mouser.com/datasheet/2/196/infn_s_a0004848050_1-2271349.pdf 

Please take a look at the block diagram on page 17.  It looks like it has a 125KHz receiver.

[T800XC]

Originally Posted by STJIM

...Please take a look at the block diagram on page 17.  It looks like it has a 125KHz receiver.

Yes, I have the datasheet too. Although the chip includes and supports the 125kHz receiver, it doesn't mean that LDL implemented it.

I've got a damaged sensor so will take another look at the PCB to see if pins 10 & 11 are used. My recollection is they were not, and hence the LF receiver not being present.

[STJIM]

Yup, that could be true.  But it seems impractical not to implement that for QC testing after the sensor is assembled.  How else would they wake it up for testing ?  Spin it ?  Or rely on a timer ?  That would take too long to do the testing.  And at 125 KHz an antenna isn't even needed and the wavelength at 125 KHz is about 2,400 meters - way too long to be looking for an antenna.

Looks like they just use a tank circuit at the input of the 125 KHz receiver not an antenna as such. 

For an example chip :

https://datasheet.octopart.com/ATA5283P-6APJ-Atmel-datasheet-35615.pdf

[T800XC]

     

Originally Posted by STJIM

Yup, that could be true.  But it seems impractical not to implement that for QC testing after the sensor is assembled.  How else would they wake it up for testing ?  Spin it ?  Or rely on a timer ?  That would take too long to do the testing.  And at 125 KHz an antenna isn't even needed and the wavelength at 125 KHz is about 2,400 meters - way too long to be looking for an antenna.

Looks like they just use a tank circuit at the input of the 125 KHz receiver not an antenna as such. 

For an example chip :
https://datasheet.octopart.com/ATA5283P-6APJ-Atmel-datasheet-35615.pdf

I found my damaged sensor and pins 10 & 11 for the LF receiver are used, which is good news. Part of the damage was to the LF circuit inductor. If the LF receiver wasn't present I suppose they could have used the programming port to test the sensor, but you're right it would be a tad impractical. I found online FCC documents for a couple versions of the LDL TPMS sensors, including schematics and method of operation from one filing, and going back to circa 2004 they had LF circuits present within the design.

I've tried reading LDL sensors on a bike this morning with the MaxiPAD and I still can't detect or wake them. The Autel MX sensor wakes and responds easily, even several inches away from the MaxiPAD on the other side of the wheel rim and tyre. I'm sure I read in one of the datasheets that there are different methods that can be used to wake the sensors, so maybe the MaxiPAD doesn't use the correct method for the LDL sensors?

Since I've at least managed to get pressure and temperature information to appear on the CAN bus using the MX sensor, but not to appear on the dash, I think that's where I'll focus for a while. Clearly the immobiliser is reading the transmitted data and is happy enough to put it out onto the CAN bus, but I'm still puzzling over the status bytes not appearing to be valid.

I used to have a small container that I'd put LDL sensors into and pressurise to 30+ psi, then by releasing pressure they started to transmit and data appeared on the CAN bus. Maybe I'll revisit that with the configured MX sensor.

[STJIM]

So the trick is to find the make/model of a certain car that uses the same protocol, I woulod think.

I think releasing the pressure worked during your test because of what I have read about the specs ( maybe the J1205 & J 1206 ?? ) for all the sensors as far as transmitting if the pressure drops a specified amount within a given time period.  I think I recall 2 conditions that must be met - one for a slow leak and the other for a larger / faster leak.  That would explain why the sensor woke-up and started sending data as you released the pressure.

Nice work !!  I admire what you are doing for this Forum , especially Tiger Tool.  Just curious, what is your background ?

One other thing :  I remember one of the guys on the Concours Forum who used the Mazda 3 protocaol to program the MX sensor said after he installed it on his bike he had to ride for 15 minutes before it started to work ( the first time ), not after the standard number of wheel rotations.  But then it worked as usual after the standard number of rotations.  That seemed kinda strange - doesn't make any sense to me ......   Don't know if that's why it might have something to do  with the pressure to not appearing immediately on your test set-up after the data is seen on the CAN bus.

[T800XC]

!!! SUCCESS !!!

I decided to risk killing my MX-sensor by continuing to reprogram it and lost count of the many, many 100s of variants I tried and how many hours I've spent on this in recent days, but it was worth it IMHO.

The sensor that I found a few days ago was clearly sending data back that the immobiliser could use, but there was something missing. Also, I couldn't wake the sensor or get it to transmit without sitting it on the MaxiTPMS PAD and interrogating it. I even attached it to the end of a thin piece of wood and spun it in my hand-drill at speed for 10/15 minutes and it still wouldn't wake (I think my arm is still shaking!). I know not all TPMS sensors have the accelerometer function enabled and instead rely on the slight change in temperature and/or pressure inside the tyre to wake, so I wasn't too concerned.

I went back to the list of sensors in the software and carried on with the tedious task of finding another that worked. After a bit of a break last night while I went out for curry & alcohol I got back to it this morning. I then found another sensor type that responded with data on the CAN-bus, but this time the pressure also started to appear on the dash of my virtual Tiger 800. 

I tried the 'wake-up on a spinning stick' method again to see if that worked, but it didn't. So I put the sensor into a jam jar (all I could find that seemed suitable at short notice), fitted a valve to the lid and used a bicycle pump to pressurise it. Lo & behold the sensor wakes on a simple pressure change and the data appears on the dash's LCD.

Now there are two minor caveats that I must mention, but will be easily overcome...the valve on the programmable Autel MX sensors is straight rather than angled, and the diameter is 11mm whereas the old Triumph one I measured is 8mm.

So there is a cheap aftermarket alternative to using Triumph TPMS sensors that work at 433MHz. The best bit for those who like to have more than one set of wheels is that sensors can be cloned with the same IDs so there's no need to reprogram the TPMS data in the immobiliser when wheels are changed.

Originally Posted by STJIM

Nice work !!  I admire what you are doing for this Forum , especially Tiger Tool.  Just curious, what is your background ?

Electronics (36+ years) in fibre-optic equipment, with additional software & mechanical backgrounds. e.g. I have a lathe and CNC mill in my shed for the fun metal bashing stuff. Everything else is just playing and trying to figure out how stuff works.

[STJIM]

Congrats !!!!!

A lathe and a CNC mill !!!    I envy you  !!!   I have a nice little wire welder and a drill press but I have to farm-out any machining.  Luckily there is an independent MC shop neaarby that has a lathe & mill and he does small jobs at a reasonable cost.

So what make / model did you hit on or did you stay with the 030190 PN ?

I didn't think the straight stem would be a big problem, but the difference in stem diameter might be.  The hole could be drilled out, of course.  The correct "recess" diameter is also required.   BigRed didn't seem to have an issue on the Concours.  I'll send him a post asking about that.