A reliable source informs me that when he accidentally dropped a USB lead into a full cup of coffee, Windows informed him that it had found new hardware. Well, indeed it had, but not an actual peripheral.
However, it would be possible to do this. Get a USB cable and put a number of sensors on the end. At this point, i could just go "blah, blah, blah", but i won't. However, i will inevitably get some of this wrong. This is how it works:
The peripheral is built into the USB plug and looks identical from the outside. It detects conducting fluids by default, so if nothing else is picked up, it simply identifies it as such.
If the level of current is comparable on the way out compared to the way in, the fluid is interpreted as a salt solution.
One contact on the plug is copper, one zinc, so if it's in an acid, it works as a battery. This is reported as sour. It can also measure alkalis, but i don't know how. There is also a white LED and a photocell. These can report the colour of the liquid and sometimes hazard a guess, for example, an acidic orange liquid is interpreted as orange and a salty red liquid as blood. There is also an array of antibodies which react to antigens, mainly proteins, allowing certain proteins to be identified such as milk protein - these would have to be changed every time it was used. Tannins enable alkaloids to be identified - they "curdle" them and the alkaline pH allows them to be identified as something like nicotine or caffeine.
In order to slow corrosion, the plug is flushed with isopropanol after use, and when it actually corrodes, it can be changed.
I know this is seriously underbaked, but i'm sure something can be done with it.
-- nineteenthly, Oct 23 2008

Not this USB_20Coffee_20Mug
Completely different [nineteenthly, Oct 23 2008]

Agilent http://www.chem.agi.../pages/default.aspx
Lab-On-a-Chip manufacturers [wagster, Oct 24 2008]

Two Cups of Coffee Two_20Cups_20Of_20Coffee
One of my favorites [csea, Oct 25 2008]

Hmm, this looks like coffee, smells like coffee, and tastes like coffee. Better ask the very coarse algorithm to be sure though.
-- Texticle, Oct 23 2008


now all we need is a laptop that will run longer when given coffee (it's battery runs low, it's 'tired', and goes into standby mode ('sleep' or 'dozing off') given coffee, it stays awake!
-- theperson10, Oct 23 2008


A mini pH meter along with your photocell might be sufficient. A 4oz. mini meter goes for 56 USD online. Below is an example of what liquids can be roughly distinguished based on pH alone.

Substance pH
Acid Mine Runoff -3.6 – 1.0
Battery Acid < 1.0
Gastric Acid 2.0
Lemon Juice 2.4
Cola 2.5
Vinegar 2.9
Orange or Apple Juice 3.5
Beer 4.5
Coffee 5.0
Tea 5.5
Acid Rain < 5.6
Milk 6.5
Pure Water 7.0
Blood 7.34 – 7.45
Sea Water 8.0
Hand Soap 9.0 – 10.0
Household Ammonia 11.5
Bleach 12.5
Household Lye 13.5

-- daseva, Oct 24 2008


This is a lot more bakeable than you seem to think. LOC (Lab-On-a-Chip) devices are all the rage these days and can easily be USB powered. Just buy one from these guys (link) and write the drivers.
-- wagster, Oct 24 2008


I was thinking Lab on a Chip, actually, but i can see a lot of irreversible processes happening which would gum things up, so i envisage disposable parts like urine or pregnancy testing strips. I'll look at the link. Thanks.
-- nineteenthly, Oct 24 2008


Found new hardware: ROHYPNOL
Found new hardware: RED BULL
Found new hardware: MD 20/20

I shudder to think what it will report after your porn fest.
-- phoenix, Oct 24 2008


CHOCOLATE ! CHOCOLATE !

(Damn, why did we ever try to assimilate Deana Troi ? STUPID STUPID STUPID)
-- 8th of 7, Oct 24 2008


You really have your chem-shit together. You think it's half-baked, but your description paints it as an all-in-one instant analysis tool. Build it and they will come.
-- MauiChuck, Oct 25 2008


//It can also measure alkalis, but I don't know how.//

That's got to be worth a [marked-for-tagline].
-- Wrongfellow, Oct 25 2008


I suppose you could always cheat by having a USB connector on the coffee cup. Maybe it could tell you temperature as well.
-- Ling, Oct 25 2008


What if it found two cups of coffee? [link]
-- csea, Oct 25 2008


That would be a huge improvement!
-- 4whom, Oct 25 2008


You could get a virtual cup of coffee if you forgot to remove hardware before drinking it. Or would it get corrupted (perhaps turn into tea) when it was halfway down?
-- Ling, Oct 26 2008


Now you need to add a new line:

NEED NEW HARDWARE: TUMS. Install Y/N?
-- elhigh, Oct 28 2008


Found New Hardware: CUP OF COFFEE
Found New Hardware: DIGESTIVE SYSTEM
Found New Hardware: CIRCULATORY SYSTEM
Found New Hardware: KIDNEYS
Found New Hardware: SEWER.
...
-- nineteenthly, Oct 28 2008


"Do you wish to safely eject the hardware ? OK/Cancel".

"OK"

<SPLOSH>
-- 8th of 7, Oct 28 2008


Decaf: instant.

Abort! Abort!
-- 2 fries shy of a happy meal, Oct 29 2008


What happens if two of these are plugged into each other.... found new hardware... myself!.. but how can that be, if I'm myself who are you?? Smoke starts rising. Croissant starts toasting.
-- xenzag, Oct 29 2008



random, halfbakery