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Cell Phones Could Sniff Out Deadly Chemicals
Hugh Pickens writes "Science Daily reports that Homeland Security's Science and Technology Directorate's Cell-All is an initiative to equip cell phones with a sensor capable of detecting deadly chemicals. A chip costing less than a dollar would be embedded in cell phones and programmed to alert either the cell phone carrier to the presence of toxic chemicals in the air, and/or a central station that can monitor how many alerts in an area are being received. While one alert might be a false positive, hundreds would indicate the need for evacuation. 'Our goal is to create a lightweight, cost-effective, power-efficient solution,' says Stephen Dennis, Cell-All's program manager. Does this always-on surveillance mean that the govenment can track your precise whereabouts whenever it wants? On the contrary, DHS says; Cell-All will operate only on an opt-in basis and will transmit data anonymously."
You mean this?
Ah the The Vaughans, I have waited patiently for years to link to thee.
Cheers, Chris
Now I have to turn off my cellphone when I cook meth.
You should do that anyway.
http://viaspace.com/ms_about.php
Awesome now another chip in my phone to help trim away my already bad phone battery life!
Most broad spectrum gas detection sensors generally work by heating up a strange oxide catalyst and measuring a resistance change. Not entirely unlike an O2 sensor in a car exhaust system.
You can buy a gas sensor off the shelf from boutique online stores for about $5 each, so $1 in bulk wholesale is believable, or at least possible.
The problem is power consumption. Check out a MQ-4, at a whopping 750 mW heater power. Thats probably more than the entire rest of the phone at peak. And the heater has to preheat for a minimum of 24 hours to provide good data, this is not something that "goes to sleep mode". Thats 3/4 of a watt, all day, every day. It will literally make a poor hand warmer in ones pocket.
http://www.sparkfun.com/commerce/product_info.php?products_id=9404
http://www.sparkfun.com/datasheets/Sensors/Biometric/MQ-4.pdf
The parts in the sensor are not cheap. The manufacturer is already highly motivated to make it as small and light as possible, which would incidentally make it low powered. At this time, thats the best "we" can do with current technology. Its not like I cherry picked the highest power unit available. However, higher power would imply bigger would imply more durable, so I'd think a cell phone model might actually be worse.
My very-much-non-smartphone uses a 3.7V lithium battery and runs "several days" between charges. Lets claim 4 days. So, 5 volts / 33 ohms = 150 ma times 5/3.7 (voltage upconverter) means 200 ma continuous draw from my 3.7V battery. 200 ma times 24 hours/day times 4 days, equals about 19 AMP-HOURS just to run the gas sensor. We'll add another amp-hour to run the phone itself, and round up to 20 AH.
Batteryspace sells a nice 20 AH lead acid battery... 14 pounds, 7 inches by 3 inches by 7 inches. Rechargeable lithium, maybe half that size and weight. We are looking at the revival of the "bag phone" circa 1980s.
http://www.batteryspace.com/sealedleadacidbattery12v20ah240whs.aspx
I would qualify this idea as an epic fail.
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
How were you modded insightful?
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My sig will be released in 2015 third quarter. Rating pending.