Custom USB tyre pressure monitoring interface

**silvi4000** · 03-22-2008, 02:56 PM

this is a very interesting idea.

Im curious how does the sensors get power?

It would suck to have to take your car to the tire shop every time the battery runs out on the sensors.

**2k1Toaster** · 03-22-2008, 03:22 PM

Originally Posted by silvi4000

this is a very interesting idea.

Im curious how does the sensors get power?

It would suck to have to take your car to the tire shop every time the battery runs out on the sensors.

They do use a battery. Usually a little watch battery. But by using cmos chips and very very very low standpower power, the batteries last for years. But when the battery dies, yes you have to go and replace it by taking the tire off. This is true in any wireless tire pressure system, even stock ones.

However there was a guy in our university who for a senior design project successfully made a pressure sender with a small power generator that uses the wheels rotation to generate energy inside the car and charges the battery. But I dont think any marketable sensors do this.

**silvi4000** · 03-22-2008, 04:55 PM

Originally Posted by 2k1Toaster

They do use a battery. Usually a little watch battery. But by using cmos chips and very very very low standpower power, the batteries last for years. But when the battery dies, yes you have to go and replace it by taking the tire off. This is true in any wireless tire pressure system, even stock ones.

However there was a guy in our university who for a senior design project successfully made a pressure sender with a small power generator that uses the wheels rotation to generate energy inside the car and charges the battery. But I dont think any marketable sensors do this.

Thats I was thinking, having a small off center load to generate power under speed changes. I guess that would make the sensor bigger and more expensive.

**Blue ZX3** · 03-22-2008, 06:50 PM

If the batteries last for years then who would care, just replace them when you replace the tires..

**juve021** · 03-22-2008, 08:03 PM

Robby, Dejan or anyone else...

So I have built the interface and paired sensors and I have initial values for the sensors but today I went to adjust my tire air pressures and the values using the TPMS Doctor, did not change and have not changed at all! Whats going on? Why isn't it refreshing with new values?

**mrbean_phillip** · 03-22-2008, 08:14 PM

How much did you change the pressure by?

Should be approximately 0.28bar (28kpa)

If your system detects new values if you clear the data in the PIC (by using the TPMS Doctor), it works.

Install it in your car, and take a drive - it will start to read increasing tire pressures, and higher temps.

Enjoy.

**juve021** · 03-22-2008, 09:19 PM

Originally Posted by mrbean_phillip

How much did you change the pressure by?

Should be approximately 0.28bar (28kpa)

If your system detects new values if you clear the data in the PIC (by using the TPMS Doctor), it works.

Install it in your car, and take a drive - it will start to read increasing tire pressures, and higher temps.

Enjoy.

I changed the psi by like 8-10 psi and the values didn't change. I performed the data reset like Robby mentioned and it cleared all the readings from the PIC but now no new readings are shown. Its like it doesn't refresh the values of the sensor.

**Robby BMW** · 03-23-2008, 11:00 AM

Are you sure that you didn't performed a "Master Reset"?
Remember, the "Data Reset" deletes the latest data received from the sensors, but the "Master Reset" also removes any sensors associations.

**HiJackZX1** · 03-23-2008, 02:29 PM

Originally Posted by silvi4000

Thats I was thinking, having a small off center load to generate power under speed changes. I guess that would make the sensor bigger and more expensive.

I think they last 5 to 7 years

**juve021** · 03-23-2008, 02:52 PM

Originally Posted by Robby BMW

Are you sure that you didn't performed a "Master Reset"?
Remember, the "Data Reset" deletes the latest data received from the sensors, but the "Master Reset" also removes any sensors associations.

Yup I'm sure, only a data reset