LowPowerLab Forum
Hardware support => Moteino => Topic started by: WhiteHare on August 31, 2015, 03:23:37 PM
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Thinking of a quick hack to modify one of:
(http://i.ebayimg.com/00/s/MTAwMFgxMDAw/z/oW0AAOSw~gRVyiiS/$_57.JPG)
http://www.ebay.com/itm/2xSUPER-LED-SOLAR-POWER-RECHARGEABLE-PIR-MOTION-SENSOR-SECURITY-LIGHT-DOOR-WALLS-/252053834350?hash=item3aaf944a6e-SOLAR-POWER-RECHARGEABLE-PIR-MOTION-SENSOR-SECURITY-LIGHT-DOOR-WALLS-/252053834350?hash=item3aaf944a6e
to include a Moteino inside and thereby make an inexpensive outdoor motion sensor. I like that it's solar powered, but if it were to get direct sunlight I suppose the sun might heat it up to 150F or maybe more inside. What's the practical upper limit for how hot a temperature it's safe to operate a moteino?
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if it were to get direct sunlight I suppose the sun might heat it up to 150F or maybe more inside. What's the practical upper limit for how hot a temperature it's safe to operate a moteino?
I'm not sure where you're located but it seems unlikely that the temperature would go that high given that the enclosure appears to be metal (shiny at that) and attached to a wall. Maybe the wall is a super insulator, but most construction materials would act as a heatsink to some degree and only a portion of the enclosure is a solar collector.
I don't know the answer to your question, but I've had motes running in my Workshop loft when its reached 118 degrees during the heat of the day without failure. I'd be more inclined to expect battery failure before the Mote fails and, since this is a commercial unit where presumably they'd be out of business if the batteries routinely fail, that further reinforces my suspicion that the temps don't reach a point of failure. However, this is pure speculation on my part ;)
Tom
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I was thinking of using a similar LED outdoor assembly with built-in solar panels earlier. It should be noted that this panel is only providing 2V and it seems to have a single 1.2V battery to hold the charge. I'd expect a direct connection between the 2 using a protection diode. This is not going to drive the Moteino without a step-up converter of some kind. But there are many kinds of similar LED nigt lights on the cheap...
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I'm in Texas, and the sun is truly fierce in July and August.
Looks as though for ATmega168/328 maximum ratings
Operating Temperature.................................. -55 C to +125
According to the RFM69 datasheet, the absolute maximum temperature it can tolerate is 115C.
So, aside from the battery, what else might fail? Isn't it usually a capacitor? Are they all ceramic on the Moteino? I don't know enough to ID what they are made from or have a good guess as to what their upper temperature limit is for continuous use.
I picked 150F as a hopefully worst case, only because I've read that some asphalt roof shingles can get that hot under the sun, because that's the only top of mind reference that I have, imperfect though it is. Polished metal isn't very emissive though, so it might get just as hot or maybe even hotter, so it's just a ballpark figure.
It's frustrating to shop for consumer gear. For instance, I'm now realizing the picture I posted above probably doesn't even have PIR, even though it says it does. I say that because I found what looks like the same thing on Amazon, and it makes no mention of PIR, and there's no obvious visual indication either that it might be there.
I thought the metal would be preferable to plastic, despite the emissiveness problem, if only because I've seen plastic get yellower and yellower after hours of sun exposure accumulated on some expensive Optex PIR sensors I once had. So, I could address the emissiveness by painting it, but then that's more work for me. Or, I suppose I might just as well paint a plastic enclosure, and then it wouldn't yellow. However, in both cases, that's me doing the work and not chinamation, which is where it should be done. Furthermore, anything that isn't metal or painted will probably fog over under sun exposure, including the epoxy enclosing the solar cell itself, plastic lensing, etc., since it's not behind glass. Argh, so often it seems there's just almost never any consideration whatsoever given to product longevity...
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Uh, yeah. I remember I was eyeing a variant of this one (http://www.ebay.com/itm/16-LED-Solar-Power-Motion-Sensor-Garden-Security-Lamp-Outdoor-Waterproof-Light-/151713489739?hash=item2352d4234b), exactly because its cover around the solar cells is made of aluminium alloy where the sun hits it the most.
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I wouldn't worry about emissivity. It's conductivity that you care about. You want the enclosure to conduct the heat into the mounting walls and away from the heat source.
Texas? Been there, done that. I had moisture sensors installed 6" underground reach temperatures of 117 degrees by mid-day. The WORST thing that happens, besides battery contacts corroding, is the PVC NEMA 4 enclosure edges curling up from the heat! Aluminum? Excellent. Stainless? Wow, if you can afford it. Plastic? NFW!
However, besides all that, do you really need to have a light that emits only 12lumens in the best case? As a 'security' light? Uh, I'll bet you could find SOME other power source for this application. And I'll bet you can find a PIR sensor you can rely on.
Tom
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@Kobuki Not bad. If mounted on a north facing fench wall, it might be the best. For a different direction, here's a stainless steel one that may be angled to catch a bit more energy:
(http://ecx.images-amazon.com/images/I/61JbqKXCooL._SL1000_.jpg)
http://www.amazon.com/Wireless-Activated-Security-Lighting-Staircase/dp/B00N4L1VMS/ref=pd_rhf_gw_p_img_2?ie=UTF8&refRID=1D65EW5ZSC31X002TNB4
I'd still prefer to know the heat risk, if any, to the capacitors though...
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Uh, yeah. I remember I was eyeing a variant of this one (http://www.ebay.com/itm/16-LED-Solar-Power-Motion-Sensor-Garden-Security-Lamp-Outdoor-Waterproof-Light-/151713489739?hash=item2352d4234b), exactly because its cover around the solar cells is made of aluminium alloy where the sun hits it the most.
@kobuki
By chance I noticed a few reviews on youtube for it while I was looking for something else :
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Yeah, thanks. Though my purpose was rather removing the light and hack some other electronics and a moteino inside. I didn't need a night light. But these have a solar panel + charger and plenty of space inside for so little money they're asking to be hacked. OTOH, you could even order one and tuck in any temperature sensor you can find to check the inside temperatures if that's your only fear.
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I had moisture sensors installed 6" underground reach temperatures of 117 degrees by mid-day.
What part of Texas was that? I don't think my soil temperatures ever exceed 80-85 degrees at that depth. The "cold" city water comes out of the tap at about 80+F during the hottest part of the summer, which still seems freakish to me.
Nonetheless, that temperature would be cool compared to above ground, so for the longest time I've been thinking it would make sense to have just the solar panel and antenna and "peripherals" like LEDs or sensors above ground and plant the rest of it, especially batteries, into the ground. For one thing, it would address my safety concern about using Lithium batteries in the heat because if, worst cast, it burst into flames, I don't know that it would cause any danger at all if it were buried.
That idea starts to fail though if your underground temperature reaches 117 degrees at 6 inches. In such a case I guess you'd just have to dig deeper (not necessarily easy if your native soil is rocky) or else go for something shaded above ground.
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You should have no issues from -20 to 130 - FAHRENHEIT, tested by myself in various deployed nodes around the home.
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I had moisture sensors installed 6" underground reach temperatures of 117 degrees by mid-day.
What part of Texas was that? I don't think my soil temperatures ever exceed 80-85 degrees at that depth.
Georgetown, just north of Austin. Yes, the 'soil' was very rocky (actually layers of limestone separating thin layers of some kind of sandy dirt). That particular sensor was in the middle of the sunny 'lawn' (if you can call burnt Buffalo grass that). The temperature sensor type was an MCP9700 IIRC with a PIC processor and Linx 418MHz transmitter module 'tucked' away, in the shade of a tree, in one of those 4" PVC NEMA 4 boxes whose edges curled from the heat after 5 years... Still the whole thing ran for years on two AA Lithium batteries.
Tom
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I had moisture sensors installed 6" underground reach temperatures of 117 degrees by mid-day.
What part of Texas was that? I don't think my soil temperatures ever exceed 80-85 degrees at that depth.
Georgetown, just north of Austin. Yes, the 'soil' was very rocky (actually layers of limestone separating thin layers of some kind of sandy dirt). That particular sensor was in the middle of the sunny 'lawn' (if you can call burnt Buffalo grass that). The temperature sensor type was an MCP9700 IIRC with a PIC processor and Linx 418MHz transmitter module 'tucked' away, in the shade of a tree, in one of those 4" PVC NEMA 4 boxes whose edges curled from the heat after 5 years... Still the whole thing ran for years on two AA Lithium batteries.
Tom
That's interesting. I'm in Austin, so I guess the temperature difference must be due to all that hyper-expensive water I'm foolishly dumping onto my mostly green St. Augustine lawn. So, I guess the ground temperature difference is mainly, or at least partly, due to cooling from evapotranspiration and the way living grass reflects IR and green wavelengths and the way dead grass doesn't reflect IR or (obviously) green wavelengths either.
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So, I guess the ground temperature difference is mainly, or at least partly, due to cooling from evapotranspiration and the way living grass reflects IR and green wavelengths and the way dead grass doesn't reflect IR or (obviously) green wavelengths either.
Yes, very likely. The case that I cited occurred toward the end of a very long dry spell where no amount of watering would help so I simply gave up. Buffalo grass can deal with that to some extent. St. Augustine probably won't.
When I first deployed my moisture sensing units, I proudly told a colleague (who was born and raised in TX) at work about it. His comment was, "What's it gonna tell ya? That its dry?"
Yup, that's pretty much it.
Tom
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I have a moteino inside my car engine bay for months and nothing stopped working until now. I have made about 3 hours or continuous rides with it next to the 90º Celsius engine and never stopped working.
As far as I know, there is a slight shift on the transmitting frequency when the crystal is heated but I still get a very good range out of it, even from inside the metal structure of the car.
Top notched peace of technology!!! ;) ;) ;) ;)
Just go ahead with that project and don't forget to shows us some pics.
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His comment was, "What's it gonna tell ya? That its dry?"
;D That's a good story. ;D
I think for indoor PIR I'm going to try an Optex EX-35R, which is intended to be battery operated and allegedly draws just 3.5uA while in standby and has a wide 2.3 to 10v operating voltage. Looks like they can be acquired for around $30. One thing I don't know is whether the Moteino will fit comfortably inside it or not, but I'm hopeful.
Panasonic used to (still does?) make a 1uA PIR sensor element, but I can't seem to find anywhere that has it in stock. It would have cost around $15 for just the PIR element itself, and I think that's a fair price if it can really do its business. It would be easier and require much less maintenance than a solar installation. So, I mention it here in case anyone finds that intriguing and wants to chase one down for themselves.
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This EX-35R looks like a really good candidate. Its casing is purposefully built with a lot of extra space inside to accomodate a battery and a radio transmitter.
Datasheet. (http://www.optex.co.jp/e/sec/download/catalog/EX_35.pdf)
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I have a moteino inside my car engine bay for months and nothing stopped working until now. I have made about 3 hours or continuous rides with it next to the 90º Celsius engine and never stopped working.
As far as I know, there is a slight shift on the transmitting frequency when the crystal is heated but I still get a very good range out of it, even from inside the metal structure of the car.
Top notched peace of technology!!! ;) ;) ;) ;)
Just go ahead with that project and don't forget to shows us some pics.
I'd probably need your amazing OTA programming technology before I could attempt such a feat because it will need to be weatherproof. ;)
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re: Panasonic 1uA PIR do you mean this one;
http://uk.farnell.com/panasonic-electric-works/ekmb1103112/sensor-motion-12m-black/dp/2095745
EKMB1103111
Anyone tried one?
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re: Panasonic 1uA PIR do you mean this one;
Good find! Yes, that one and the 1uA variations in that data sheet: http://www.farnell.com/datasheets/1537855.pdf
The prices, at least in the US based Element 14, seem very high though (maybe because their inventory is in the UK?)
Also, looks like Digikey has them after all: http://www.digikey.com/product-search/en?
http://www.digikey.com/product-search/en?s=16115&FV=ffe831e5&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=500
For whatever reason, they didn't seem to show when I looked previoiusly.
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re: Panasonic 1uA PIR do you mean this one;
Good find! Yes, that one and the 1uA variations in that data sheet: http://www.farnell.com/datasheets/1537855.pdf
The prices, at least in the US based Element 14, seem very high though (maybe because their inventory is in the UK?)
Also, looks like Digikey has them after all: http://www.digikey.com/product-search/en?
http://www.digikey.com/product-search/en?s=16115&FV=ffe831e5&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=500
For whatever reason, they didn't seem to show when I looked previoiusly.
I cannot seem to find them for less than £15 odd, which is $25 ish
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I'd like to note that this Panasonic one is the bare sensor. You'll need a shelter that fits the Moteino, the battery, possibly a movement indicator led, etc. The Optex one has it all and consumes 3.5 uA sleeping, which is 99.9% of its operation. The +2.5 uA doesn't make a difference in reality.
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The +2.5 uA doesn't make a difference in reality.
Why doesn't it make a difference?
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Was that really a question?
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I have a moteino out on the balcony where it gets afternoon tropical sunlight every afternoon. I regularly see temperatures in the high 50 degrees (Celcius). Haven't noticed any problems and even the 3 x AA batteries powering it are still running at 4.37V DC after 2 or 3 months in service.
This compares favourably with 6 other moteinos in rooms in the house.
The moteino in the fridge runs at between 3 and 5 degrees Celcius and it's battery pack is the lowest of the 8 systems at 4.29V DC after 2 or 3 months operation.
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Can I ask what types of batteries are you using? Especially in the fridge. BTW, doesn't your fridge act as an RF shield? Are you having any kind of problems with that mote?
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Just using standard AA energizer batteries. No problems getting the RF out of the fridge which is a new model Samsung. I am updating all 7 wireless nodes at 5 second intervals to the 8th node connected to small PC in the middle of a 1300sq ft apartment.
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In my outdoor weather unit I have recorded temps as high as 115 degrees inside the enclosure on many days in a row. No problems.
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Just closing the loop: I received the EX-35R, and I measured it's idle current. If powered at 3V, it does indeed seem to have somewhere between 3uA and 4uA current (spec sheet says 3.5uA current). If powered at 9v, it has 8uA current, at least by my measurements, which were made using a Fluke 87V in combination with Dave Jones's uCurrent Gold. Even when activated following a confirmed detection (confirmed by pulse count that is), it didn't consume more than about 50-60uA at its peak, and the activation doesn't last longer than 5 seconds. So, it does seem very energy efficient.
Also, there's ample space in the back compartment for batteries and a Moteino. It could easily accomodate 3x AA. It might even accomodate c-cells, though I haven't tested that idea yet. Anyhow, there's a *lot* of space.
It's an open question as to how well it would hold up if exposed to rain. It doesn't look watertight to me, and I'm pretty sure heavy rain might get into it. I think it's probably meant for indoor use, but maybe (?) it would do OK in some covered outdoor locations where it's not getting heavily soaked. Or maybe you could just put it into some kind of watertight enclosure that can pass IR. Without making it ugly by covering all the edges in silicone, I imagine there should be some way to make it work outdoors. On the other hand, maybe if the power source really could last 10 years or longer, I could just seal it up with no intention of ever opening it again...
The one drawback is that it seems to take about 2.5 seconds to trigger after the initial detection, whether it be in 2 pulse count or 4 pulse count mode. It's much faster in "walk test" mode, which doesn't pulse count, but that consumes 9ma (how much of that is from the red LED I don't know) and obviously doesn't have the 2 minute wait for activity to cease before retriggering that the pulse modes have.
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Recently we had an upgrade in our alarm system. I asked the folks a few practical questions. They primarily work with Paradox equipment (our system was working swiftly for about 18 years before starting to choke, and finally a lightning strike nearby has done it in somehow). They said that for outdoors op, you need to get an outdoors sensor, the indoor units are not really up for the task. It might be just the lack of proper weatherproofing, but also temperature tolerances. They also said that the Paradox wireless motions sensors can run on a set of 3 AA alkalines for about 3..5 years. Not bad. Yours is a general Optex one, and the lifespan of the batteries highly depends on what you put behind the sensor in the box. Oh, and the apparent slowness is not incidental, it's to minimise the radio transmitter activity of the sensor to save battery life. It should react quickly for the first detection but then it slows down until it stops sensing more motion in its range. Test mode/walking test is to support testing the sensor array and the alarm system at installation.
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Uh, yeah. I remember I was eyeing a variant of this one (http://www.ebay.com/itm/16-LED-Solar-Power-Motion-Sensor-Garden-Security-Lamp-Outdoor-Waterproof-Light-/151713489739?hash=item2352d4234b), exactly because its cover around the solar cells is made of aluminium alloy where the sun hits it the most.
I came across a picture of what one might look like inside:
(http://ecx.images-amazon.com/images/I/61dHyvEPVcL._SL1000_.jpg)
http://www.amazon.com/Zitrades-Lighting-Waterproof-Landscape-Courtyard/dp/B011E1V7PU/ref=pd_sim_sbs_86_3?ie=UTF8&dpID=51IDQAyLQoL&dpSrc=sims&preST=_AC_UL160_SR160%2C160_&refRID=1103F8FY2HBF83G9E5EE
That particular one is 3x the price, but it seems to have also gotten more favorable reviews.
Sealing against moisture is probably key to any worthwhile longevity. My wife purchased some cheap $1 garden path lights, and they barely lasted a couple of months before corrosion from moisture intrusion caused them all to fail one by one.