Gadget Freak Case 145: A Barometer That Measures Your Height
Mark likes to know how much pressure he is under
Design News Staff -- Design News, July 31, 2009
Here's a weather instrument - the Dodecahedral Barometer - that can actually determine how tall you are by reading the barometric pressure between your head and your feet. Mark Thoren notes that his gadget was inspired by the release of some new electronic products. The first is a Serta model 270 barometric pressure sensor that recently came on the market. The sensor is inexpensive and accurate to the point of being suitable for weather stations. The other items that make this gadget possible are some new HP displays that make the gadget's readings visually appealing.
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Part Description |
Allied Part # |
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Hex Display |
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4 character, alphanumeric display |
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Octal edge triggered latch |
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1 |
Quad Digital Isolator |
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1 |
Board; Copper Clad; 1/16 thk; double sided; 1oz copper; high temp |
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I agree with the other comments regarding the poor editing and posting. If you folks are going to publish, take some pride in it! To the author.. When you share a good idea like this, please post the code as well. Evan if it is not commented well it would help us understand your approach. I realize this was done as a lark, but a 20 bit A-D linked to a pic is much more valueable than you may realize. The analog parts of this project are of great value to many of us in real world applications. I suggest you publish this in EDN or Circuit Cellar as a feature article. Thanks
Charles Howey - 2009-4-9 14:25:44 EDT -
Can somebody fix the link for the complete build?
JCA - 2009-24-8 13:50:01 EDT -
I checked ebay and found one used sensor for $25 buy-it-now, but is it untested, sold as-is. NEW sensors on ebay and www.plccenter.com/buy/SETRA/270 are going for $400+. That's not what I'd call inexpensive!!! VERY cool sensor and project though!
I agree with the comments about problems with the DN Gadget Freak web site. I can't count how many times I have run into broken or incorrect links on this site. Also, The Parts Lists are almost NEVER anywhere near complete. How can a parts list for a project like this NOT include the central component?? (Hopefully someone from DN reads these comments and cleans up this site!)
Don - 2009-3-8 10:12:28 EDT -
Mark, Isn't it cool to see the look on peoples faces when you display the altitude difference right in front of them? I introduced my SENTEK altimeter 20 years ago. Changing the sensitivity to display in inches instead of feet usually amazed people. (although once an angry disbeliever told me, "You programmed it just to display THAT"). I used the old SENSYM transducers. Each one had to be tweaked with temperature and slope compensation, but they were cheap.
Darrell Hambley - SENTEKengineering
Darrell Hambley - 2009-2-8 14:09:46 EDT -
Thanks for the comments... Yup, it's definitely not a mattress. And the parts (displays in particular) definitely weren't new - they were scavenged from ancient equipment but Allied still carries them! (I'll keep this in mind for repair jobs.) This was an extension of Linear Tech design note 456, if you want more theory.
I just wanted to put my shiny sensor in a cool box and waste (I mean spend) Sunday mornings writing C code.
Mark Thoren - 2009-1-8 01:29:20 EDT
A Barometer That Measures Your Height
07/31/2009A Barometer That Measures Your Height
07/31/2009
