Is this wireless setup possible? (Power supply question)
Is this wireless setup possible? (Power supply question)
(OP)
Hi all,
I plan on contracting technology to have an electronics device built, but before I do I want to see if the energy demands can be met. It's a simple strain gauge (http://www.vishaypg.com/micro-measurements/stress-...) that I want to attach to some type of small microcontroller/radio antenna. The unit will monitor strain in the strain gauge, and then when the strain reaches 2%, it will record 100 data points a second to a small flash drive for a total of one minute and then stop recording. During the course of a 50 year period, it may only reach that 2% strain no more than 10 times. That being said, the strain gauge must be continously monitored so that it knows when it has passed this 2% strain limit. Then, if the data ever needed to accessed, a reciever can send a signal to the device and have it read back the stored data on the card. This recieving process would occur no more than 20 times thoruhgout the lifetime of service. My question is, we want this technology to be solely powered by batteries, and not have to be replaced. Is there a battery that is capable of powering this unit as described for this amount of time, or is this expectation completely unreasonable? Any insight would be much appreciated.
I plan on contracting technology to have an electronics device built, but before I do I want to see if the energy demands can be met. It's a simple strain gauge (http://www.vishaypg.com/micro-measurements/stress-...) that I want to attach to some type of small microcontroller/radio antenna. The unit will monitor strain in the strain gauge, and then when the strain reaches 2%, it will record 100 data points a second to a small flash drive for a total of one minute and then stop recording. During the course of a 50 year period, it may only reach that 2% strain no more than 10 times. That being said, the strain gauge must be continously monitored so that it knows when it has passed this 2% strain limit. Then, if the data ever needed to accessed, a reciever can send a signal to the device and have it read back the stored data on the card. This recieving process would occur no more than 20 times thoruhgout the lifetime of service. My question is, we want this technology to be solely powered by batteries, and not have to be replaced. Is there a battery that is capable of powering this unit as described for this amount of time, or is this expectation completely unreasonable? Any insight would be much appreciated.
RE: Is this wireless setup possible? (Power supply question)
I believe you will need to think out-of-your-current-box. Can you remote the batteries to somewhere accessible?
Does this all happen in the pitch black? Can you not cram a tiny solar cell somewhere?
Is this somewhere energy harvesting can be applied? If it's a bridge or a tower there may be sufficient vibrational energy to run the system.
This company has THE longest lasting batteries available. My 25 years "guess" seems to be spot-on if you note the headline on the home page.
http://www.tadiranbat.com/
Keith Cress
kcress - http://www.flaminsystems.com
RE: Is this wireless setup possible? (Power supply question)
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RE: Is this wireless setup possible? (Power supply question)
What you want is beyond the self-discharge of typical battery technologies. You will have to go to a parasitic power approach - be it thermal, vibration, EM field, micro-solar, whatever. Alternately you can go for a type that would be periodically recharged using a RF or magnetic field - somewhat like a RFID reader that would query the device and at the same time put more energy into it. But even the typical power storage source for parasitic power or RFID devices (supercapacitors) have leakage currents 5X what the AMR industry would consider adequate.
The military does use some special battery technologies that can be 'activated' after years of storage - usually by a small pyrotechnic charge that opens a small chemical vial. Maybe a setup with several of these where when one battery reaches the end it activates a new battery every 15 years or so.
I know - everything I can think of is too complex, too expensive, or too large for your application. Good Luck!
RE: Is this wireless setup possible? (Power supply question)
RE: Is this wireless setup possible? (Power supply question)
http://www.mayoclinic.com/health/pacemaker/MY00276...
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RE: Is this wireless setup possible? (Power supply question)
RE: Is this wireless setup possible? (Power supply question)
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FAQ731-376: Eng-Tips.com Forum Policies
RE: Is this wireless setup possible? (Power supply question)
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RE: Is this wireless setup possible? (Power supply question)
In the realm of impractical exotic expensive power sources, your question made me think of a device I read about a few years ago. A radio-active alpha emitter packaged so it bombarded some substance creating free electrons, and would work as a power source providing a few uA of power to a device for years. Was about the size of a tube of lipstick. I believe it had a price tag that would even make the military wince!
50 years is a LONGGGGGGGG time for a power source - even the Voyager 1 and 2 spacecraft are only 35 years old, and I don't think they're projected to last 50 years on the RTG that powers them (radioisotope thermoelectric generator). BTW It's expected any day now that NASA will announce that Voyager 1 has officially left the solar system into interstellar space.
RE: Is this wireless setup possible? (Power supply question)
RE: Is this wireless setup possible? (Power supply question)
One of my lighting products spends most of its time in sleep mode, waking about 10 times a second (if memory serves) to check on the state of a pin (relatively high-impedance, say 100k)... average power draw is under 50uA. That includes time (and power) to start and stabilize the clock with each wakeup. I was duly impressed with such low power requirements, but you need to power up and read an A/D converter, as well, and that typically requires time to stabilize, which means even more power. I wouldn't expect to eat less than several hundred uA, at best, though to be fair that is merely a guesstimate. Interested in hearing how it turns out.
Dan - Owner
http://www.Hi-TecDesigns.com
RE: Is this wireless setup possible? (Power supply question)
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Is this wireless setup possible? (Power supply question)
Keith Cress
kcress - http://www.flaminsystems.com