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CleanSpace CO Sensor Runs On Freevolt RF Harvesting 110

mspohr writes: A few years ago, a Kickstarter was set up to develop a locator tag powered by free radio frequency (RF) energy harvested from the environment. This was called a scam here on Slashdot and was shut down before it was funded on Kickstarter. However, it now appears that the concept is not as far-fetched as some predicted. A UK company CleanSpace has developed a carbon monoxide (CO) sensor which is powered by free RF. A review of the product has been posted on YouTube. It uses Freevolt technology to keep a battery charged and the CO sensor running. Since they have several thousand of these devices collecting data, they do appear to work and it seems to be in the 'not a scam' department.
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CleanSpace CO Sensor Runs On Freevolt RF Harvesting

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  • You can run a CO detector on it. You might be able to run a smoke detector on it, although you'd think they'd be doing that if they could. Perhaps you could run a wireless keyboard or mouse over a very short range. Harvesting radio noise isn't a new idea.

    It's not a general battery replacement. Their website says "RF Energy Harvesting For the Low Energy Internet of Things" which is a fairly ugh slogan, but it seems relatively accurate. I don't see any reason why you couldn't fire up a microcontroller, do a little bit of sampling, and report your results before going back to sleep until the next time your capacitor was full.

    • by mattack2 ( 1165421 ) on Thursday July 14, 2016 @05:48PM (#52514281)

      But isn't it also very limited by how many people try to do the "RF Energy Harvesting"? and line of sight? The guy 'behind' the other one who did the RF harvesting won't have as much energy to harvest..

    • >> You can run a CO detector on it

      Better not run CO or smoke detectors.
      If you wifi fades, or your detector is in a blind spot of your wifi (and these can move over time), then you will potentially die.
      Don't do that. it'S dangerous.

      Also. Its still BS to call that "free" energy. There's no such thing.

      • I don't get your reasoning.

        If you have no CO detector, you die as well ...

        • by stooo ( 2202012 )

          Perhaps, but then it's your own fault.
          A safety device that's defective by design is not allowed...
          If people die, the manufacturer, and the seller will be held liable. At least that's in Europe.

          • And why should it be defective by design?

            Sorry, you make no sense.

            Also, a CO sensor is not necessarily a "safety device".

            Perhaps I simply want to have one?

      • by mspohr ( 589790 )

        Free to me, that is...
        I get free energy from the sun on my solar panels.
        This device captures RF energy in the environment. Someone had to pay to put it there but it's free for me to harvest.

    • by AmiMoJo ( 196126 )

      Smoke detectors have to be extremely reliable, so they don't use RF harvesting. In order to have a large enough store of energy to sound the siren for long enough they would need a battery anyway (probably NiMH for safety). Easier and cheaper to have a simple disposable battery that is replaced periodically, and which can beep for weeks when the battery is getting low.

      RF harvesting is an interesting idea but of somewhat limited utility. A simple and extremely low cost solar cell is usually preferable, unles

      • Easier and cheaper to have a simple disposable battery that is replaced periodically, and which can beep for weeks when the battery is getting low.

        Some detectors have a lithium primary cell wired in and fixed in place so it's not replacable. They generally last for the entire recommended lifespan of the detectors, so when the battery dies it's time to throw the detector away anyway.

        • They generally last for the entire recommended lifespan of the detectors, so when the battery dies it's time to throw the detector away anyway.

          And since detectors already require special recycling, it's a plan with no drawbacks. I like it. We have one wired and one battery-only detector in our house, and I've gone through about three nine volt batteries in a decade. It's not a horrible hardship, but it's still an annoyance.

  • However, the amount of power is available is very small, and is not suitable to power wifi or bluetooth devices - even BLE. This does not mean in principle you can't use it for things that use orders of magnitude less power.

    • by Qzukk ( 229616 )

      is not suitable to power wifi or bluetooth devices

      What?! Are you telling me I can't scavenge enough power from background RF noise to broadcast a signal stronger than the background RF noise?!

      • by MightyMartian ( 840721 ) on Thursday July 14, 2016 @05:57PM (#52514333) Journal

        "Curse you, thermodynamics! I'll get you next time." (jumps into perpetual motion flying machine and plummets to earth)

      • It won't work continuously, but for burst transmission it might.

      • is not suitable to power wifi or bluetooth devices

        What?! Are you telling me I can't scavenge enough power from background RF noise to broadcast a signal stronger than the background RF noise?!

        Actually, in theory, yes, you could - collect stray RF energy 99.99999% of the time, and transmit in very brief bursts.

      • is not suitable to power wifi or bluetooth devices

        What?! Are you telling me I can't scavenge enough power from background RF noise to broadcast a signal stronger than the background RF noise?!

        Well... There is this giant shiny thing in the sky during the day that puts out a LOT of background RF energy - some of it you can even see. If only there was a way to harvest that. :-)

      • by Khyber ( 864651 )

        "Are you telling me I can't scavenge enough power from background RF noise to broadcast a signal stronger than the background RF noise?!"

        Depends on the noise level of the wavelength you want to overpower versus the power in the wavelength you're harvesting from!

      • by segin ( 883667 )
        You can, actually, but only for very short bursts, and then you must idle for quite a while to charge back up.
      • is not suitable to power wifi or bluetooth devices

        What?! Are you telling me I can't scavenge enough power from background RF noise to broadcast a signal stronger than the background RF noise?!

        Actually, you can do this, just not in real time. For instance, you can scavenge the power and store it in a super-cap and then use it, but probably only for a very short burst. Think of it as an air compressor running a tool that utilizes more cfm than the compressor can produce. The compressor fills the tank, the tool drains the tank and then you must sit and wait until the tank refills to use the tool again. Not necessarily practical if your needs are great, but certainly doable.

      • by unrtst ( 777550 )

        What?! Are you telling me I can't scavenge enough power from background RF noise to broadcast a signal stronger than the background RF noise?!

        Actually, by harnessing the harmonic frequency of the incoming waves of disparate sources, they are capable of amplifying the power generated enough that they can sustain a stable and comparably strong signal generation.

      • I imagine you can as long as you 'scavenge' for longer than you 'broadcast' and you have somewhere to keep your scavenged energy in between transmissions.
    • Some more research finds that some instances of the blurb say it uses the RF to 'boost' the battery on the device.
      In principle, the device is large enough that a $1 battery would run it for years. In some cases (if you put a phone on top of it) it will actually probably net charge. In a normal office environment, it will not.

      Note also https://store.clean.space/prod... [store.clean.space] "Battery Life: Up to 5 years"

    • by mspohr ( 589790 )

      Actually, the CO sensor they have built transmits data to your smartphone using Bluetooth so they do seem to have enough power for Bluetooth (not sure if it's BLE).

      • There is also a large battery in, which has enough energy to power an infrequent (30s?) BLE sample for the specified battery life of 5 years. This raises the obvious question of if the wireless energy harvesting does anything in most cases.

        • by mspohr ( 589790 )

          I don't know of any rechargeable battery which will go for five years without charging. Most rechargeable batteries have a substantial self discharge rate and will go to zero in a few months with charging.
          I can't find anything on the size of the battery but the whole device is only 51 grams so it would be difficult to fit a "large" battery in there.

          • by jiriw ( 444695 ) on Thursday July 14, 2016 @07:39PM (#52514983) Homepage

            Most rechargeable batteries have a substantial self discharge rate and will go to zero in a few months with charging.

            This used to be the case, but for a decade or so now there are rechargeable 'ready to use'/'low self-discharge' (LSD) NiMH batteries on the market that can hold a significant amount of their charge for several years (for good ones, 75% after 3 years). LSD NiMH's do have a bit smaller capacity per volume but that is maybe a 10-20% difference, at the most.

            But maybe these sensors have a rechargeable Li-Ion battery? I don't know about LSD types of those but Li-Ion have very bad charging characteristics when almost empty (high internal resistance - so it's harder to charge the emptier it is) so I don't think they are useful when recharging in these extremely low power conditions. And then there are supercapacitors, but they have a way too high self-discharge rate to be able to claim 5 years of operation on the 'battery' alone.

          • so perhaps they are using the RF charging to help keep the battery in that weird 'goldilocks' zone where the battery's life span is best, like the one that they ship smartphone batteries at, what is it, between 40-80%?
          • 'Large' in this case is a 450mAh lithium-ion battery (as shown in a teardown).
            Properly chosen lithium ion do not suffer from self-discharge much.
            This weighs about 15 grams. The battery will permenantly lose some capacity - but as the discharge is very slow and at very low rate, most of the capacity will be usable.

            • So you are saying that this is a scam and they aren't even trying to capture and store energy?

              • Not quite. The hardware is capable of energy recovery and in some circumstances may extend the battery life.
                It's just that in most circumstances, for most users, it is going to be largely, or entirely reliant on battery to the point that it will work just fine for 5 years without any energy recovery.

                If, for example you put it close - 50cm? to your phone or router, it may actively stay charged, and not discharge at all.

                But, the battery is large enough, with low enough self discharge that it meets the publish

    • http://www.eevblog.com/forum/r... [eevblog.com] - I am unsure if this link will work. This shows a teardown of a tag.
      On eevblog, under the title "weird "energy-harvesting" broadband (?) antenna ".

      This shows a 450mAh rechargable lithium-ion battery.
      http://www.ti.com/ww/en/wirele... [ti.com] - this is a TI device which is designed for sensor tags, and sports a 1 year battery life reporting once a second over BLE with a 2032 battey. This is one half the capacity of the lithium battery used.
      It also won't be sending data at one second

  • From the scam article: " this one claims it doesn't require any batteries

    From the current article: " It uses Freevolt technology to keep a battery charged

    Can anyone spot the difference?

    • From the scam article: " this one claims it doesn't require any batteries

      From the current article: " It uses Freevolt technology to keep a battery charged

      Can anyone spot the difference?

      It's marketing speak.....it doesn't 'require' any batteries because it's already got one.

      Of course it needs a battery to work, it just doesn't require one yet, ergo it "doesn't require any batteries".

  • by citylivin ( 1250770 ) on Thursday July 14, 2016 @06:28PM (#52514561)

    Localizers here we come! Vernor Vinge would be proud!

    http://blog.regehr.org/archives/255 [regehr.org]

    https://en.wikipedia.org/wiki/A_Deepness_in_the_Sky#Localizers [wikipedia.org]

    • by Agripa ( 139780 )

      Localizers here we come! Vernor Vinge would be proud!

      Ubiquitous law enforcement here we come! Vernor Vinge wouldn't be proud!

  • by bobbied ( 2522392 ) on Thursday July 14, 2016 @06:55PM (#52514719)

    Oh come on. I've seen the "I can run my on harvested RF energy!" scams come and go on Slashdot. Yes, they get shot down, but not for being *technically* impossible, but being *practically* impossible.

    Yea, you can transfer energy using RF from one point to another without wires, but the problem here is it's pretty inefficient to do this because the amount of power falls by at least the square of the distance. So what may work at 1' fairly well using 10 watts of input RF power, is going to require something like 100 watts when you double the distance and 1,000 when you double it again (4'). (Please feel free to correct my math, but you get the idea).

    So, yes, if you have a "low power" device, something that doesn't consume much power on average, you can likely scavenge enough power from the RF around you in most places to keep running. HOWEVER, most of the scam devices are for applications that REQUIRE always on radios and significant computational power. These devices consume too much power to be practically powered by foraging RF energy, especially in the home or office where the largest amount of RF power is likely coming from your Part 15 regulated WiFi devices which are limited to about half a watt and can be tens of feet away.

  • I worked on this (Score:5, Informative)

    by Anonymous Coward on Thursday July 14, 2016 @07:23PM (#52514879)

    I've worked on this project and it doesn't work.

    Basically all it is is an antenna with a half bridge diode rectifier. This is pretty straightforward however the problem is that despite using 'zero drop' diodes the ambient RF energy does not produce a sufficient voltage (power out of the antenna with the line impedance at the diode) to switch the diode properly which causes a rapid drop off in efficiency. Basically the diode is still in the sloped part of the IV curve (zoom in on an IV curve at the knee). This combined with the fairly low amounts of power available means that the power output of these things is in the 10s of uW, which is less power than is consumed by the charge pump needed to top the battery up! So how does it work then? Check the tear down photos and you'll see a massive battery...

    The other interesting thing about this 'technology' is that you can calculate the energy density of a harvester, it's simply the mean time till failure x power output / volume of device. When you do this calculation you quickly realise that due to the size of the antenna needed to see any appreciable power the device would have to last for 10-20 years to begin to approach the energy density of even coin cells (including the casing)!

    • Why don't people with useful things to say get Slashdot accounts anymore? It's hard to tell the wheat from the chaff when it's all Anonymous Coward.

      I used to think having a Slashdot Id was cool, and it was in the 90's/00's. Times have changed I guess.

    • Yes, this is correct.

      The diodes are operating in their Square Law region, which means that as an RF Detector it must be woefully inefficient.

      Knowledge which should be routine for any RF engineer, or for any kid who has built a Crystal Set.

    • by AmiMoJo ( 196126 )

      I've worked on similar projects, also using vibration to harvest energy via MEMS devices. It works but you have to have a realistically low power budget. I was able to run a clock/hydrometer off an FM band tuned antenna, but it was fairly large (30cm). Generally speaking solar is usually a better bet.

    • I experimented with this myself. I actually managed to get 50mV out of my setup! It helps that I used a slightly cleverer rectifier and a great deal of wire strung all around the room as an antenna.

      Then I turned off the light.

      Turns out the reason I got so much power was the presence of a nearby radio transmitter: The switching power supply in my CFL light bulb was putting out a ton of noise at 200KHz and all the harmonics thereof. Turn it off and the device output drops to practically too small to measure.

      I

  • The fact this works doesn't make the other any less a scam. The prior project still doesn't work and the analysis is still valid. Unless there is a design using freevolt to make the other a reality it's completely irrelevant.

  • One of the side-effects of this device, implicit in its design, is that it will re-radiate mixing products of all received signals. This tends to interfere with nearby radio reception.
  • AM Radios (Score:4, Interesting)

    by Sir Holo ( 531007 ) on Friday July 15, 2016 @04:56AM (#52516579)

    I built an AM radio – with no battery – that would audibly play local stations. This was in the 1970s.

    Surely many slashdotters did the same. Heath-Kit.

    • I made devices to light up a little LED or move the needle of a galvanometer only using the electricity harvested from radio waves. They are resonators, like most antennas anyway, which implies that they only harvest around a given frequency, say 100 MHz FM broadcast or 900 MHz cell phone communication. The "snake", intended for FM broadcast waves, has a LED that will light up a little bit even a few kilometers away from an average powerful emitter. It can easily feed a low-power LCD calculator. http://www [4p8.com]
  • by Anonymous Coward

    This trend has been ongoing for decades. People with no STEM aptitude that are heavily enthused by "science" (or rather their pop-culture knowledge of science) with loud obnoxious voices declaring science is known, that the limits are what they have been fed through limited education and with a degree of arrogance combined with zealotry unseen since the dark ages.

    This is exactly why pop-science shouldn't be a thing - the idiots of the world are better off raving about petty divisive non-issues like those i

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