Quote:
Originally Posted by Bob Denman
(Pretend you're talking with someone who has NO idea what you're talking about...  )
Is there a practical use for this knowledge; or is it best to just purchase a tire pressure and temperature monitoring system?
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LOL! Yeah just pick up a TPMS and don't worry about this.
I'm basically reverse engineering the hardware so I can write my own software for the TPMS. The sensors don't output numbers in the units you want (it'd be great if the pressure sensor just spit out a PSI value every few seconds, but it doesn't do that). Instead, what they did is use the range of available values and scale it to that range.
Lets say you had a system that let you transmit only the number values from 0 to 200 (for whatever reason). You want to make best use of what is available so you scale your sensor output to that range (say you have a voltage sensor that outputs 0-20V). Then you'll want to transmit a value that takes advantage of the available values so you transmit the sensor value multiplied by 10 (then the receiver divides by 10 and displays xx.x values).
My graphs above are my attempts at determining what the conversion is from the raw data transmitted by the sensors to a human readable value (PSI, degrees F, etc.).
Like I said: What engineers do when they are bored... LOL math problems
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