Monitoring Home Power Consumption for less than $25 • Hacker News Board

Re: Monitoring Home Power Consumption for less than $25

#91

Post by zeep » Sat, Dec 30, 2017, 3:31 PM UTC

PostOnce wrote: post #2

Tangential, but what other fascinating things can I do with an SDR dongle? I've had one for years and have not heard of this. * Listen to various radio stations * Track airplane positions * Receive weather images from a satellite what else? One other thing off the top of my head is combining ship position and cargo databases: https://github.com/marcdacosta/ambient-shipping

You can read TPMS sensors in car tires, wireless weather stations and much more, see this app: https://github.com/merbanan/rtl_433 for more examples.

Re: Monitoring Home Power Consumption for less than $25

#92

Post by SergeAx » Sat, Dec 30, 2017, 3:33 PM UTC

gh02t wrote: post #88

matthewmacleod wrote: post #82

Earlier quoted context omitted.

They’re not. I’m confused why you think this would be particularly expensive, though; the components aren’t that expensive, and neither is data service for the minimal data the meter will send. I would imagine it’s more expensive than a PLC or general radio solution, but on the other hand it’s got the benefit of requiring minimal new infrastructure.

Considering the alternative is employing a person who has to go around and read every meter versus the very low cost of a GSM radio I think it very clearly makes sense cost wise.

The alternative is to use more appropriate tech for once-a-day/once-an-hour tiny data transfer, like LPWAN. Maybe NFC-like tech, when the host device is installed in a car, which drives around the block once a day/week.

Re: Monitoring Home Power Consumption for less than $25

#93

Post by SergeAx » Sat, Dec 30, 2017, 3:43 PM UTC

matthewmacleod wrote: post #90

SergeAx wrote: post #87

Earlier quoted context omitted.

GSM assembly with SIM holder costs about $5 in a mass-production-wise quantities. I don't know about UK, but here in Russia typical "dumb" resource meter costs between 10 and 30 USD. Smart meter could not be more than 2x expensive to be competitive. So you should squeeze all other functionality into $5 production cost just to have zero margin, and you should completely forget about autonomy. And I don't even want to…

You’re ignoring the marginal cost of requiring meter reads with dumb meters, though, let alone any other benefits that the meter might offer. I agree that the WAN tech is perhaps more suitable in theory, but that ignores the fact that there is already a ubiquitous GSM network in place.

Hope UK has 100% GSM coverage, otherwise you have to set up brand new GSM cell to read meters from a remote village, which is 1000-10000 times more expensive than LPWAN base station with active signal amplifier and/or relay station. Pulled a feat like that in Siberia just two days ago)

Re: Monitoring Home Power Consumption for less than $25

#94

Post by qaq » Sat, Dec 30, 2017, 3:45 PM UTC

I wonder if there are people who abuse this to reduce their bill or to run up someone else's bill.

Re: Monitoring Home Power Consumption for less than $25

#95

Post by zzzcpan » Sat, Dec 30, 2017, 3:47 PM UTC

matthewmacleod wrote: post #90

SergeAx wrote: post #87

Earlier quoted context omitted.

GSM assembly with SIM holder costs about $5 in a mass-production-wise quantities. I don't know about UK, but here in Russia typical "dumb" resource meter costs between 10 and 30 USD. Smart meter could not be more than 2x expensive to be competitive. So you should squeeze all other functionality into $5 production cost just to have zero margin, and you should completely forget about autonomy. And I don't even want to…

You’re ignoring the marginal cost of requiring meter reads with dumb meters, though, let alone any other benefits that the meter might offer. I agree that the WAN tech is perhaps more suitable in theory, but that ignores the fact that there is already a ubiquitous GSM network in place.

GSM network can be used to aggregate data from cheaper devices near by. Putting GSM into every device is somewhat silly.

But well, there is always a "preference" to solutions offered by certain companies no matter the cost.

Re: Monitoring Home Power Consumption for less than $25

#96

Post by krzyk » Sat, Dec 30, 2017, 3:54 PM UTC

SergeAx wrote: post #93

matthewmacleod wrote: post #90

Earlier quoted context omitted.

You’re ignoring the marginal cost of requiring meter reads with dumb meters, though, let alone any other benefits that the meter might offer. I agree that the WAN tech is perhaps more suitable in theory, but that ignores the fact that there is already a ubiquitous GSM network in place.

Hope UK has 100% GSM coverage, otherwise you have to set up brand new GSM cell to read meters from a remote village, which is 1000-10000 times more expensive than LPWAN base station with active signal amplifier and/or relay station. Pulled a feat like that in Siberia just two days ago)

I would expect such country like UK to have 100% GSM coverage (e.g. Poland has 100%) - it is quite densely populated - with 2G it is quite easy considering that the meters are installed usually where people live == need GSM coverage.

Re: Monitoring Home Power Consumption for less than $25

#97

Post by jdavis703 » Sat, Dec 30, 2017, 3:55 PM UTC

Heliosmaster wrote: post #42

masklinn wrote: post #30

Earlier quoted context omitted.

That's what my second paragraph is talking about. Note that "least consumption" is not the right indicator, different people have different levels of consumption. What you want is a break in the consumption pattern, a home with lower than usual consumption of electricity.

You just need to build a baseline: hide a device and record activity over a long-ish period of time and then it's easier to sense patterns

Unless your house has something very valuable, I kind of doubt most thieves would spend this much time plotting to break in.

Re: Monitoring Home Power Consumption for less than $25

#98

Post by zzzcpan » Sat, Dec 30, 2017, 3:57 PM UTC

SergeAx wrote: post #49

It is extremely strange they don't use even primitive encryption. I work for Russian company "Strizh Telematics", we are making smart resource meters. We take security very seriously here: all transmits are encrypted with 64 bit keys and data protocols are specifically protected from statistical and repeat-packet attacks.

I'm curious, if someone finds a vulnerability in your algorithms somewhere, will you be able to quickly deploy updates to all the installed smart meters? Because, honestly, "taking security very seriously" doesn't mean anything anymore.

Re: Monitoring Home Power Consumption for less than $25

#99

Post by SergeAx » Sat, Dec 30, 2017, 4:18 PM UTC

krzyk wrote: post #96

SergeAx wrote: post #93

Earlier quoted context omitted.

Hope UK has 100% GSM coverage, otherwise you have to set up brand new GSM cell to read meters from a remote village, which is 1000-10000 times more expensive than LPWAN base station with active signal amplifier and/or relay station. Pulled a feat like that in Siberia just two days ago)

I would expect such country like UK to have 100% GSM coverage (e.g. Poland has 100%) - it is quite densely populated - with 2G it is quite easy considering that the meters are installed usually where people live == need GSM coverage.

I believe you mean "100% of inhabited Poland", and even then you may be wrong. Check this map: https://www.nperf.com/en/map/PL/-/-/signal/ - there are plenty of spaces with gray "no coverage" dots for every operator. The problem is when you have bad GSM coverage in some unfortunate spot even in a big city - you may just can't solve it. And, by the way, there's a habit to place utility meters in basements, where GSM coverage is much worse.

Re: Monitoring Home Power Consumption for less than $25

#100

Post by gh02t » Sat, Dec 30, 2017, 4:23 PM UTC

SergeAx wrote: post #92

gh02t wrote: post #88

Earlier quoted context omitted.

Considering the alternative is employing a person who has to go around and read every meter versus the very low cost of a GSM radio I think it very clearly makes sense cost wise.

The alternative is to use more appropriate tech for once-a-day/once-an-hour tiny data transfer, like LPWAN. Maybe NFC-like tech, when the host device is installed in a car, which drives around the block once a day/week.

I agree, LPWAN is a better solution and this is almost exactly its raison d'etre, but the cost isn't really that much more. They're basically using GSM as an LPWAN substitute. GSM radios cost peanuts and the data costs would be pretty low since they don't need to transmit a lot. Plus, low power isn't that important since these devices are connected to mains.

> Maybe NFC-like tech, when the host device is installed in a car, which drives around the block once a day/week.

This is how my meter works (in the US) and is the same as described in the article. The meter broadcasts on the ISM band every few seconds and somebody in a car drives by while a scanning device records. Still faster than having somebody on foot walking around but I can't help but think a hub system like LoRaWAN might work better, so that no person has to go out on patrol.