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Batteries Not Included, or Required, for These Smart Home Sensors

coe.gatech.edu

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Re: Batteries Not Included, or Required, for These Smart Home Sensors

#11

Post by SimplyUnknown »

croes wrote: post #6
fragmede wrote: post #4

Earlier quoted context omitted.

The microphone is on a smart watch the user is wearing.

Do you need a signal that tells you the window is open if you are in the same room?

Obviously not, but there is larger potential than that. A microphone in a watch or phone can pick up the signal and relay the trigger to another server via for example MQTT. Then, you can have homeassistant act upon this signal.

The flow is then Open door --> Signal triggers --> Signal caught by microphone --> Microphone device relays to server --> Server turns on smart lighting in that room.

There is a lot more that you can do, but this is just an example. The microphone to pick it up is a limitations, but the gain is:

- reduced power usage as the signal generators are not power-operated

- less waste as no empty batteries need to be discarded (if non-rechargeable batteries are used)

- improved security because the signal generators are not connected to the internet, reducing the attack surface.

Re: Batteries Not Included, or Required, for These Smart Home Sensors

#12

Post by phh »

ogig wrote: post #10

I can see some uses, but calling this system batteries free seems a stretch. A sensor is worth nothing if it can't be read, and to read this you need a powered microphone and computing. Some already common magnetic door systems do the same; door plate and magnet movement is enough to create a detectable current, (using no external power), then that signal is read and computed by an electronic/digital system (using po…

I'm on the side of "clever, fun, but feels useless". But to defend the project, all sensors require a powered central system. It's pretty common for Zigbee to have one repeater per room [1], which is just what is needed for this system.

[1] Because any AC-powered Zigbee device is a repeater, so just a bulb or a plug is enough

Re: Batteries Not Included, or Required, for These Smart Home Sensors

#13

Post by harg »

There already exists "kinetic" switches for lights etc whose switch contains some passive electronics that when actuated produces enough energy to emit a radio signal that can be read by a relay module. They're pretty handy as you can basically place the switch anywhere you want without the need for the wires to be there. The relay can live in the light fitting or somewhere else convenient.

There's probably no reason why these kinetic switches can't also be used for detecting other events like doors opening/closing etc. I feel like a radio signal is a bit more reliable and easier to detect than high frequency sound.

I also think calling these a "sensor" is a bit of a stretch. They detect events but have no knowledge of the current state of the thing they're sensing. E.g. the can detect a door opening/closing, but have no idea if the door is open or closed at a given time

Re: Batteries Not Included, or Required, for These Smart Home Sensors

#14

Post by buescher »

cyberax wrote: post #8

Trivia time! The first practical wireless remote control for TVs also used ultrasound: https://www.youtube.com/watch?v=MLPk1Us62xQ

Right, and they were superseded by battery-powered infrared remotes for good reasons. I would recommend revisiting those reasons before proposing this sort of technology for wireless sensors.

Re: Batteries Not Included, or Required, for These Smart Home Sensors

#15

Post by buescher »

harg wrote: post #13

There already exists "kinetic" switches for lights etc whose switch contains some passive electronics that when actuated produces enough energy to emit a radio signal that can be read by a relay module. They're pretty handy as you can basically place the switch anywhere you want without the need for the wires to be there. The relay can live in the light fitting or somewhere else convenient. There's probably no reason…

Piezo harvesting switches and similar (I think there’s a flywheel design out there too) are quite expensive, not terribly reliable or consistent, and require substantial activation force. Conventional switches and batteries that can last for years in remote push buttons and sensors are extremely inexpensive in volume.

Re: Batteries Not Included, or Required, for These Smart Home Sensors

#17

Post by anVlad11 »

It's research, not a product. Even with that, framing it as a smart home sensor in the press release is a stretch.

1) 93.75% success rate in controlled conditions, 92.1% in a somewhat-realistic deployment scenario - too low for reliability. I wouldn't use something like that to trigger smart home automations.

2) Range hardcapped at ~1m due to how ultrasound works, you can't centralize detection. Their answer is to give everyone in the household a wearable receiver, which is eeeeeeeh idk, doesn't look consumer-friendly to me.

3) Paper suggests a mix of durable and consumable parts for the transmitter. Their numbers show that the 3d-printed PLA cantilever needs to be replaced every 900 cycles or so. Should work fine, but...

4) ...every transmitter pair needs to be tuned per-setup, every time. Not a plug&play in the consumer sense.

Re: Batteries Not Included, or Required, for These Smart Home Sensors

#18

Post by [deleted] »

phh wrote: post #12
ogig wrote: post #10

I can see some uses, but calling this system batteries free seems a stretch. A sensor is worth nothing if it can't be read, and to read this you need a powered microphone and computing. Some already common magnetic door systems do the same; door plate and magnet movement is enough to create a detectable current, (using no external power), then that signal is read and computed by an electronic/digital system (using po…

I'm on the side of "clever, fun, but feels useless". But to defend the project, all sensors require a powered central system. It's pretty common for Zigbee to have one repeater per room [1], which is just what is needed for this system. [1] Because any AC-powered Zigbee device is a repeater, so just a bulb or a plug is enough

[deleted]

Re: Batteries Not Included, or Required, for These Smart Home Sensors

#19

Post by cucumber3732842 »

anVlad11 wrote: post #17

It's research, not a product. Even with that, framing it as a smart home sensor in the press release is a stretch. 1) 93.75% success rate in controlled conditions, 92.1% in a somewhat-realistic deployment scenario - too low for reliability. I wouldn't use something like that to trigger smart home automations. 2) Range hardcapped at ~1m due to how ultrasound works, you can't centralize detection. Their answer is to gi…

From the artwork it looks like they're targeting industrial use. Seems like a low grade replacement for bar/qr code scanning. The "wearable" (more likely integrated into some other thing than worn IMO) receiver seems to point in that direction too.

Author probably has a specific use case in mind. Probably some application where EM emissions are undesirable or power is complicated that has thus far resisted automated industrial data entry. Investigating the use of something like ultrasound would align with constraints like that. Someone (department head? PR department?) said that was too niche and to make up some bullshit with mass market appeal.

Re: Batteries Not Included, or Required, for These Smart Home Sensors

#20

Post by SOLAR_FIELDS »

ogig wrote: post #10

I can see some uses, but calling this system batteries free seems a stretch. A sensor is worth nothing if it can't be read, and to read this you need a powered microphone and computing. Some already common magnetic door systems do the same; door plate and magnet movement is enough to create a detectable current, (using no external power), then that signal is read and computed by an electronic/digital system (using po…

Even the layout you describe has massive advantages over the status quo from a placement perspective. Having a reduced footprint device that goes in the actual measurement location that can phone home to a more robust central location like this is not only already very common but also the existing solutions that do it still suffer from the design constraint of requiring a battery which this innovation goes a long way towards
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