Samsung RF energy harvesting - Page 1
Forum section: electronics / general

author: f4eru
author_rank: Super Contributor
timestamp: January 04, 2022, 09:55:06 am
content: Samsung just showed RF energy harvesting.It will no doubt work when close to the transmitter, but isit really practical for everyday use?Probably not really.I would try to get one for analysis whenever possible.https://www.theverge.com/2022/1/2/22860390/samsung-eco-remote-2022-solar-rf-harvesting-charging

author: PlainName
author_rank: Super Contributor
timestamp: January 04, 2022, 12:20:52 pm
content: A TV remote is probably a perfect scenario for this kind of harvesting. Very low power sucked up 24/7 and then used rarely for a quick stab of a button. Think how long batteries last in remotes - my Logitech Harmony with LCD and backlight lasts long enough that when it does go flat I've forgotten it won't charge from the USB port and have to go through the motions of finding that out again!But... the expensive routers (they should say WAP instead, since this is sucking up WiFi stuff and not IP routing in a wire stuff) have beam forming capabilities, so the off-piste RF would likely be much less than with cheap WAPs. Could be a case of getting to production just after the technology it relies upon has moved on.

author: Haenk
author_rank: Super Contributor
timestamp: January 04, 2022, 03:22:13 pm
content: Considering I have about a dozen listed WLANs available - and that is within a quasi-rural single-family-homes-only area - it seems possible to collect enough energy over time.

author: SiliconWizard
author_rank: Super Contributor
timestamp: January 04, 2022, 08:03:10 pm
content: Yeah. Would warrant some calculations just to figure out how bullshitty this can possibly be - or not. So, would it realistically be able to get at least as much power (+ efficiency for charging) per day as an average use of the remote takes out.

author: thm_w
author_rank: Super Contributor
timestamp: January 04, 2022, 10:32:18 pm
content: The headline is RF, but it has a fat solar panel on the back that is going to be capturing 90% of the energy here:QuoteI don't see any actual specs for it. Also can charge with USBC.http://cdn.cnetcontent.com/99/b6/99b649ea-6983-49fc-9785-24f959d03951.pdfMaybe if someone gets one they can measure the charge currents.

author: Marco
author_rank: Super Contributor
timestamp: January 04, 2022, 10:36:41 pm
content: If you switch from high duty cycle IR with the standard transmitters and receivers which haven't changed for decades to something more modern, using short pulse based IR for instance, I could see a capacitor and some rectenna harvester to be sufficient.

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: January 05, 2022, 12:09:48 am
content: Won't this cause an overall increase in energy consumption, as Wi-Fi endpoints need to increase transmission power due to this device sucking energy out of the aether?

author: Marco
author_rank: Super Contributor
timestamp: January 05, 2022, 12:28:12 am
content: No, in the far field antennas cast a shadow. Pretty much irrelevant.

author: f4eru
author_rank: Super Contributor
timestamp: January 05, 2022, 05:57:50 am
content: it will work, but only like in 30% of cases, because past 2-3m, power budget will be negative.So kind of dodgy.

author: Haenk
author_rank: Super Contributor
timestamp: January 05, 2022, 07:51:13 am
content: Quote from: I wanted a rude username on January 05, 2022, 12:09:48 amI don't think so - the energy would just be absorbed by "something" (walls, air, you name it - and turned into heat).

author: PlainName
author_rank: Super Contributor
timestamp: January 05, 2022, 09:42:48 am
content: Quote from: Haenk on January 05, 2022, 07:51:13 amNot to mention that this isn't being sold as free energy, just another way of not having to keep changing batteries.

author: MrMobodies
author_rank: Super Contributor
timestamp: January 05, 2022, 02:41:13 pm
content: If they did manage to make it work could it also interfere with wifi operations like affect signal/thoughput and latency depending on how much charge it is draw from it?

author: tszaboo
author_rank: Super Contributor
timestamp: January 05, 2022, 03:38:41 pm
content: It is just virtue signaling. Rechargeable battery is only worth it, if you can charge it at least 10 times during it's lifetime, otherwise their environmental impact is larger than Alkaline batteries. With this, you need to place a rechargeable battery, a USB port, a solar panel, charge management IC, protection IC, and so on.I was basically estimating for my product, that all these cost a lot more than a simple lithium primary battery, that would also give virtually infinite lifetime to the device. Just a high quality solar panel and an energy harvesting IC costs more than the battery.

author: PlainName
author_rank: Super Contributor
timestamp: January 05, 2022, 04:13:37 pm
content: QuoteQuite possibly. And bandwagon jumping. But without such efforts many things wouldn't get a start and lead to actual useful products years later.

author: f4eru
author_rank: Super Contributor
timestamp: January 05, 2022, 05:31:29 pm
content: Who said that there are batteries inside ?It may as well be a supercap.

author: BrokenYugo
author_rank: Super Contributor
timestamp: January 05, 2022, 06:00:32 pm
content: It's a nifty concept but I'm also not sure it's all that environmentally friendly. I doubt I've ever burned through more than 2-3 sets of AAAs in a regular IR remote that was functioning correctly. I just changed out the original set in a 2013 Samsung remote, and that one has a backlit keypad.It's the RF based remotes like you find on the higher end Rokus (and probably other streaming sticks) that really tear through batteries to a point a rechargeable solution of some sort probably makes ecological and economic sense.

author: thm_w
author_rank: Super Contributor
timestamp: January 05, 2022, 10:44:54 pm
content: Quote from: f4eru on January 05, 2022, 05:31:29 pmThey call it a rechargeable battery on their website. Either way, supercap or li-ion are fairly similarly priced. Li-ion can be recycled, supercap unsure of that, it can be re-used but thats assuming it goes into the proper e-waste channel.So question is if 10 alkalines is equal to the environmental cost of a small li-ion pouch cell. I've probably gone through 10 AAA's on my TV remote by this point, its about 3-4 years old.

author: jts
author_rank: Newbie
timestamp: January 07, 2022, 06:19:20 pm
content: I'm not sure if I'm doing it right (probably not), but using the formula from EEVblog #55 , assuming the dimensions are the same as the previous model (6.46 * 2.01 inches)  and a 40 meter range  I'm getting an output of 0.04178 μW.Could that tiny amount of power be enough to do anything useful at all?https://www.amazon.com/BN59-013-Replacement-Control-Compatible-BN59-01357F/dp/B09BKCWMSZ?th=1https://www.makeuseof.com/samsung-tv-remote-power-over-wifi/#:~:text=According%20to%20Samsung%2C%20its%20Eco,by%20pretty%20much%20every%20router.

author: SiliconWizard
author_rank: Super Contributor
timestamp: January 07, 2022, 08:05:02 pm
content: Quote from: jts on January 07, 2022, 06:19:20 pmNope. But just do the math. =)Here is my (quick) take:- Let's assume the remote is reasonably efficient, and requires 15 mW of power while transmitting (about 4.5 mA @ 3.3 V, to get an idea. Not that much for a remote using IR, or even Bluetooth, so it's very likely optimistic here.)- Let's assume it draws about 1 µW when in standby. Optimistic here too IMO. Would require a very careful design.- And let's assume the total time spent transmitting in 24 h is 30 s. Depends on your use, but at least for IR, it's probably even pretty optimistic.Assuming I didn't mess up the calculation, that would be an average of 6.2 µW. And again, probably very optimistic already.Assuming you can harvest an average of 0.04178 µW, that would be 0.67% of the remote's consumption. Let's assume a 90% efficiency for charging the "battery" - probably optimistic too here - we're down to 0.54 %. Even if one managed to harvest 10 times the power you estimated, that would still be only about 5% of the remote's consumption. And again that's with pretty optimistic consumption figures IMO.But as thm_w said, it still has a solar cell, and unless you stick the remote in a drawer when you're not using it, this is where it will get most of its power from. The RF thing is marketing wank.To get an idea of a typical remote's consumption - but maybe here Samsung managed to design an ultra efficient remote: they often use 2 to 4 AAA batteries these days. Let's take the 2-battery option, with alkaline batteries, typical capacity of 1000 mAh, so about 3 Wh. If the batteries last for 2 years, that's an average consumption of about 171 µW.So, yeah.

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 08, 2022, 01:19:04 pm
content: Perhaps the best option would be a magnet in a tube that has a coil around it charging up a capacitor? Just shake it to charge it.

author: PlainName
author_rank: Super Contributor
timestamp: January 08, 2022, 02:11:54 pm
content: You may be thinking of a wanker torch. Got one, don't think I've ever managed to shake it enough for it to be useful. Still, the technology does work and a few shakes could do the biz.However, a better solution, if we're going that way, is the switch that harvests power from being pressed. Got one of those too on a doorbell - no battery, solar whatever, nothing. The act of pressing it generates enough to power an RF transmitter to get a signal to a typical wireless chime. Works very well, but the button has a little more travel than expected and feels slightly mushy. Probably not suitable for a 20-button remote.

author: nali
author_rank: Frequent Contributor
timestamp: January 08, 2022, 02:18:35 pm
content: It's far more likely to harvest RF energy from the mobile phone sat next to it on the arm of the sofa, although that's probably less marketing-friendly.

author: Marco
author_rank: Super Contributor
timestamp: January 08, 2022, 02:22:39 pm
content: Quote from: SiliconWizard on January 07, 2022, 08:05:02 pmUltra narrow band RF transceivers can communicate over kilometers with that power. A narrow pulse IR transmitter with far simpler electronics operating over less than 10 meter should be able to get a couple orders of magnitude below that.

author: tszaboo
author_rank: Super Contributor
timestamp: January 10, 2022, 10:02:54 am
content: Quote from: Marco on January 08, 2022, 02:22:39 pmThis is going to use BLE for the radio, the 5mA@3.3V is in line with the cutting edge BLE microcontrollers. You need approximately the same energy for receiving. The IR LEDs are blasted with with a lot of energy in a IR remote, because they expect to be able to receive even if you point your remote backwards, and you only get reflections from the wall.Quote from: SiliconWizard on January 07, 2022, 08:05:02 pmThese smart remotes have a lot of functionality on them. Microphone, accelerometer to start with. These will consume power even if they are sleeping. Also, I'm fairly sure the remote will have a continuous BLE connection to the TV, so a button press can happen any time, and the pairing is avoided. In my experience this paging requires anywhere 5-10 uA of current, as there is a "hello" message every 2-8 seconds.

author: SiliconWizard
author_rank: Super Contributor
timestamp: January 10, 2022, 05:58:56 pm
content: Quote from: tszaboo on January 10, 2022, 10:02:54 amYes absolutely to your points. I was being overly optimistic - as I said - on purpose. Because even in that case, the RF energy harvesting would prove completely useless.

author: Marco
author_rank: Super Contributor
timestamp: January 21, 2022, 02:40:32 pm
content: Quote from: tszaboo on January 10, 2022, 10:02:54 amOkay then it isn't credible.QuoteA couple bright ns pulses would likely be equally easy to detect as a square wave.

author: tszaboo
author_rank: Super Contributor
timestamp: January 21, 2022, 05:02:10 pm
content: Quote from: Marco on January 21, 2022, 02:40:32 pmTo be clear, this 5mA-10mA is only during transmission and reception. It operates in slots, and it is only super fast pulses, where otherwise the power consumption is 5-10uA-100uA or so in average. It all depends n the settings. Tx power, slot frequency etc.