Just got this from Futurlec:

The HP01D is the barometric pressure sensor. So looks like I'll need to find another source. Mr. Amp's english isn't too clear on whether or not I'll be getting those two parts, figure it might be a while.

Finding the serial comunications is a huge mess. Kind of wondering what sort of nighmare I walked into here. TWI and I2C seem to be the same thing, or very similar. Some AVR impliment in hardware, or sort of... but, it can be done in software. SPI is different, and may or may not be hardware, but again several software solutions. Seems like a lot of problems and questions using this stuff. Been looking for an AVR tutorial for this stuff, but looks like I'll be learning AVR stuff from a PIC site again. Wonder if Nigel's PIC tutorials has something. Haven't visited in a while....

 

Do what I do... Register with Freescale, and blag some freebies.. Plenty of pressure sensors to choose from..
Shipping time from placing my sample order was 3 days! Not bad eh?
I now have a barometric altimeter using the local QNH from Heathrow that cost me less than £10 to build..

Hope this helps..

__________________
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Shax.
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A bus station is where a bus stops...
A train station is where a train stops...
On my desk I have a work station...
Nuff Sed!!!

 

Got my Futurlec order yesterday, so have a lot of work ahead of me on this project. I'm going to try and post everything here as I progress, and hopefully keep it complete. Wish it wasn't summertime so soon, hours at work are already picking up, and a couple of minor repair jobs (hopefully), that got dump on me after Mother's Day dinner Sunday. Good news though, have a week vacation end of the month, should work out well.

Shouldn't take too long to throw this together once I figure out how to read the sensors. I want to store the min. and max. values on chip, and find what percentage of that range is the current reading. That percentage will be sent out to an LED as its brightness level. The actual numbers, precision, and calibration aren't going to be a concern, since I'm not looking to display them, just RGB levels for Temp, humidity, and pressure. Will probably use an LCD to watch numbers in the beginning, mostly to see that I'm actually getting a reading, and they change throughout the day. Eventually, I'll need to go wireless, and put the sensors outside, or just run a cable for the LED.