Custom USB tyre pressure monitoring interface

**Xargon321** · 07-23-2009, 11:10 AM

i will lok im hoping to use the same logic analyzer program to get enough samples to enable you or robbie to figure out how to implement it into some universal format.

Az1324 at the end of the day your still going to need a programmed chip it handles the learning sensors etc.

**Lok** · 07-23-2009, 01:40 PM

Az1324 I think you are hoping for a bit too much. These receivers are being built in runs of 100 boards, there is simply not enough volume to reduce the costs to that point. If I could make a run of 1000 boards the cost of the kit would easily be less than $150.

@ Xargon, i think Ax1324 is right, you won't need the PIC chip as the protocol is probably completely different. The learning process may even differ significantly. You need to get a logic analyzer and see what kind of communication is going on in your exisiting TPMS system, chances are you may need to tap into your actual TPMS electronics and see the 1's and 0's that are being transmitted on the frequency. You may not be happy with how your car looks at the end...

**az1324** · 07-23-2009, 02:01 PM

Originally Posted by Lok

Az1324 I think you are hoping for a bit too much. These receivers are being built in runs of 100 boards, there is simply not enough volume to reduce the costs to that point. If I could make a run of 1000 boards the cost of the kit would easily be less than $150.

Even at 100 qty parts costs should be <$25. It's just that expensive automated assembly line driving up the costs.

**Xargon321** · 07-23-2009, 03:08 PM

i am aware that the programming for the tpms system will likely be very different but i cant tap into my cars setup with out delving into the dash and i drive the car daily im hoping that i can use the reciver setup to capture the data packets sent by the sensors to see see if we can decode them. the main problem for me is that the tpms system is built into a smart junction box on my car that handles all the communications traffic for the car.

im using you setup as i just need a platform that i know is working and powered, i am going to use a laptop and the logic analyzer program that robbie found to see if i can capture the data packets just to see where it can go. this is just my idle tinkering and im not expecting much out of it. my programming skill are not the greatest so i would probable send you and/or robbie the data so you can have a look at it

**Lok** · 07-23-2009, 03:34 PM

Originally Posted by az1324

Even at 100 qty parts costs should be <$25. It's just that expensive automated assembly line driving up the costs.

Are you suggesting that placing the components by hand is cheaper? If that were the case then whats the point of automated machinery? why not do everything by hand? Parts actually cost much more than $25, I can tell you because I have made the bill of materials. Also parts are not the only costs associated with the device (labor, development, support, packaging, advertising). Even after the product has left my facility I still have to provide support in case there are issues or people need help getting software installed. Also I am not sure if you know this but my parent company is a Contract Electronic Manufacturer so I am getting the boards manufactured with internal pricing, I don't think you will find too many developers in the Car PC industry with the kind of resources I have. I operate out of the US so I can't pay my employees 50 cents an hour like they do in China.

**WuNgUn** · 07-23-2009, 04:48 PM

Originally Posted by Lok

Do you have the LED version of the board??? If so then there are two LED's on the device, one should remain on once the USB link has been established and the other should blink every time you recieve a new packet.

Red is on when plugged in...red flashes when new data arrives. Haven't seen the green LED do anything yet!

**az1324** · 07-23-2009, 06:21 PM

Originally Posted by Lok

Are you suggesting that placing the components by hand is cheaper? If that were the case then whats the point of automated machinery? why not do everything by hand? Parts actually cost much more than $25, I can tell you because I have made the bill of materials. Also parts are not the only costs associated with the device (labor, development, support, packaging, advertising). Even after the product has left my facility I still have to provide support in case there are issues or people need help getting software installed. Also I am not sure if you know this but my parent company is a Contract Electronic Manufacturer so I am getting the boards manufactured with internal pricing, I don't think you will find too many developers in the Car PC industry with the kind of resources I have. I operate out of the US so I can't pay my employees 50 cents an hour like they do in China.

Obviously automated is better but usually involves high setup costs so small runs are hard to justify.

I'm not trying to imply that you are adding unreasonable markups I am simply saying it would be possible to get the receivers made and distributed much more cheaply if different choices were made. Personally I would be happy with a $30 unassembled receiver kit and no tech support but that's just me. I think plenty of people are happy with what you are offering.

**Lok** · 07-24-2009, 08:56 AM

Originally Posted by WuNgUn

Red is on when plugged in...red flashes when new data arrives. Haven't seen the green LED do anything yet!

I belive Robby may have made the changes to the latest firmware which only required 1 LED as opposed to two. Let me do some testing with a new board and get back to you.

**WuNgUn** · 07-26-2009, 03:12 PM

I've also had strange data readings...
I don't think my front 2 wheels have updated since I 'learned' them...I've gotten new data from the rear, but it never updates regularily.
Actually, I recieved data on the front right once...but that's it.

Could it be the reciever is too CLOSE to the front? It's mounted INSIDE the center of the dash, behind the touchscreen...