Journal Alioth's Journal: Good grief! 6
So I'm looking for a barometric pressure sensor.
I saw what looked like a good one - a small sensor which would output 0.1 to 5.1v depending on the pressure, and measured from 800mb to 1100mb. Absolutely ideal.
The first warning bell was that although the website had a few items you could buy directly by credit card through their online shop, this particular device did not and had no price. Prior experience says that anything where they don't advertise a price means inordinately expensive. I thought it would probably be $50-$100.
Well, I was an order of magnitude out. Nearly $500 just for the sensor (and probably $600 by the time I've paid for shipping and import taxes).
No Frickin' Way.
So I'm on the lookout for the pressure sensors that exist in inexpensive electronic barometers. The barometers exist, but nowhere have I found the actual component. Now I know what someone will reply - buy one off eBay and desolder the sensor.
Unfortunately, that means I still don't have a data sheet. It's likely it'll be connected to some ASIC (for which I won't have a data sheet either). I presume an electronic barometric pressure sensor is going to be some kind of quartz crystal with a vacuum chamber on one side, whose frequency will change depending on how hard the atmosphere is pushing on it. So I'd need to know what it's nominal frequency is - and probably most importantly, because I bet these baro sensors are actually really good temperature sensors but very poor pressure sensors - how to account for temperature, i.e. find the pressure needle in the temperature haystack. So I also must have a data sheet.
Farnell don't sell one. RS don't sell one. Web searches only bring up ones labeled as "low cost" - for values of "low cost" if you're the Government or a manufacturer of weather stations for the Government. You can tell it's not really "low cost" because they usually give you an individual person's email address to ask for a price quote. Any time it's worth a company giving out a sales droid's individual address or telephone numbers we're talking about high cost, high margin products (probably another order of magnitude higher than the first sensor I enquired about!)
Sigh.
I thought about possible solutions while at the gym tonight (having successfully recovered from Saturday's session, where I decided my legs weren't getting a good enough work out so slung on a random quantity of extra weights and ended up hurting for two days). About the only viable solution I can think of short of finding an actual pressure transducer IC that costs tens of $CURRENCY rather than hundreds or thousands is to find an electronic barometer on ebay with a serial port.
On the gym - this is the first time since I got back from Houston that anyone else has been there while I was there. I prefer to be on my own at the gym, because then people can't snicker at the tiny weights that I can manage (I'm up to 30 kilos on the bench, although it is free weights not a machine!). The two who were there when I arrived tonight, I've seen a few times before. One is good looking and slim and about my height and the other is head and shoulders taller than me - but probably twice my weight (i.e. quite severely overweight). Both are probably in their early 20s. It's quite interesting seeing how they work out (or don't). The slim one does a little bit here and there, but spends 60% of his time chatting or looking out the window in to the pool, while the overweight one works out continuously. Come March, I just know who's going to be the fittest of those two, and it ain't gonna be the slim good looking one!
Psst... (Score:2)
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Shudder. Might as well go back to IE 6 then.
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I suppose I'll have to get used to it if some of my favorite
But dear lord, why the fuck must every single piece of software that allows post and reply style conversations re-invent the freaking wheel for interfaces. I mean there was decent newsreader software that supported threads 20 years ago. I still have yet to see any sort of web based forum or blog
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Try asking over here... (Score:1)
(PS: Not everyone has moved to Multiply.)