Clean looking sensor node
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Epilogue: I get a call from Digikey to tell me that they can't ship the button cells by first class mail because they contain lithium. Mind you, I only ordered 3 of them. Instead, they can only be shipped by either UPS ground or FedEx ground, both of which will cost me about $10 for the shipping alone. :grimacing: Yet, USPS apparently had no trouble delivering the CR2477 button cells from China using ePacket delivery. Argh, it's all just ridiculous!
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@NeverDie no, USPS are not ok with that. http://pe.usps.gov/text/pub52/pub52c6_004.htm#ep270347
@mfalkvidd said:
@NeverDie no, USPS are not ok with that. http://pe.usps.gov/text/pub52/pub52c6_004.htm#ep270347
Not that it matters, but I wonder why is it acceptable for lithium batteries to be shipped installed in equipment, but unacceptable if not installed?
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@mfalkvidd said:
@NeverDie no, USPS are not ok with that. http://pe.usps.gov/text/pub52/pub52c6_004.htm#ep270347
Not that it matters, but I wonder why is it acceptable for lithium batteries to be shipped installed in equipment, but unacceptable if not installed?
@NeverDie my guess is that the rulemakers took a pragmatic approach. Banning batteries in equipment might have been too hard, which could have brought down the entire proposition. So they opted for rules that are less safe than total ban, but more safe than no rules at all.
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@NeverDie my guess is that the rulemakers took a pragmatic approach. Banning batteries in equipment might have been too hard, which could have brought down the entire proposition. So they opted for rules that are less safe than total ban, but more safe than no rules at all.
My two cents :D
Batteries inside equipments are protected from shock by said equipment, shocks/bending beeing one of the main reasons for battery fires.
It could also be related to the "density" of batteries. Having one battery burning inside an equipment will slow down the propagation of the fire and is relatively easy to deal with a fire estinguisher.
Having a fire in one battery that will propagate to other batteries shipped together is a nightmare.But I'm surprised they apply this rule (that I thought were made to deal big rechargeable batteries) to a bunch of button cells
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LOL. This is the ultimate catch-22: I can't mail the falsely advertised batteries back to China, even if I wanted to! The only way to do it would be to first install them in some equipment and then ship the equipment, but then they would be used batteries and no longer new, so the seller could refuse a refund on those grounds. Since returning them is impossible, maybe I can appeal to Ali Express for a refund without returning them. This is becoming entertaining.... A refund from Ali Express would almost cover the cost of shipping from Digikey.
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I just received the white version and it's gorgeous ! Ordering bunch now to put everywhere in the house :D
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Link is here but unfortunately it says "no more available" :(
Found some here at 3€ :
https://www.aliexpress.com/item/Qi-Wireless-Newest-Charger-for-iPhone-Samsung-Galaxy-S3-S4-Note2-Nexus-All-free-shipping/32735986077.html -
And same seller has one it seems, at 2€78, but only interesting if you buy 1 item to get free shipping, else the one at 3€ is cheaper as there's no limit in item count for free shipping option
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@NeverDie I found a good way to open them without any damages.
I have that cheap DIP chip extractor that's very bad at doing it's job, but it happens that it's the perfect size to fit in the vents at the bottom, if you put it inward and pull you can pop up the bottom cover easily.I bought 10 white chargers from the "woweinew" shop for 30$ with China Post Registered Air Mail included after a few seconds of negociations.
I also found some SMD 7021 breakouts with only minimum components onboard, they are a bit more expensive but save some space in PCB surface and thickness. And no need to waste time removing and shorting the voltage regulator.
https://www.aliexpress.com/item/Industrial-High-Precision-Si7021-Humidity-Sensor-with-I2C-Interface-for-Arduino/32524005324.html
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Just FYI: it turns out you have to avoid exposing the si7021 sensor to high humidity (>80%) unless you turn its buiilt-in heater on--which, unfortunately, will drain a battery rather quickly. It's in the datasheet, but not as prominently as it should be. Therefore, going forward, I'm switching to the BME280, which costs more but appears not to have this issue. I do have some si7021's, but I think I'll probably only trust the temperature reading and consider the humidity reading as a rough gauge only.
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Link is here but unfortunately it says "no more available" :(
Found some here at 3€ :
https://www.aliexpress.com/item/Qi-Wireless-Newest-Charger-for-iPhone-Samsung-Galaxy-S3-S4-Note2-Nexus-All-free-shipping/32735986077.html@Nca78 said:
Link is here but unfortunately it says "no more available" :(
Found some here at 3€ :
https://www.aliexpress.com/item/Qi-Wireless-Newest-Charger-for-iPhone-Samsung-Galaxy-S3-S4-Note2-Nexus-All-free-shipping/32735986077.htmlThe first link has them back in stock. I just now ordered one from them.
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Just FYI: it turns out you have to avoid exposing the si7021 sensor to high humidity (>80%) unless you turn its buiilt-in heater on--which, unfortunately, will drain a battery rather quickly. It's in the datasheet, but not as prominently as it should be. Therefore, going forward, I'm switching to the BME280, which costs more but appears not to have this issue. I do have some si7021's, but I think I'll probably only trust the temperature reading and consider the humidity reading as a rough gauge only.
@NeverDie said:
Just FYI: it turns out you have to avoid exposing the si7021 sensor to high humidity (>80%) unless you turn its buiilt-in heater on--which, unfortunately, will drain a battery rather quickly. It's in the datasheet, but not as prominently as it should be. Therefore, going forward, I'm switching to the BME280, which costs more but appears not to have this issue. I do have some si7021's, but I think I'll probably only trust the temperature reading and consider the humidity reading as a rough gauge only.
Yes I have seen that but I wonder how much the "drift" really is. As long as the temperature is still precise (and it is from my observations) a drift in humidity measurement is acceptable, as long as it can still reflect changes. I've also ordered BME280 (6 pins version with no voltage regulator) from 2 different suppliers anyway, so I will be able to compare sensors side by side with every other part coming from the same batches.
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Great. I'd be interested to hear of any conclusions you might reach from whatever comparisons you're able to perform.
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At the moment I have still not received my BME280 sensors so I'm testing with the si7021 only.
For the first step I have put 3 of them on top on each others and checked their reported values over nearly one week.
I must say I'm very impressed by what I have seen at the moment, the maximum temperature span I have seen was 0.3°, and 3% for humidity.
Now I can confirm the sensors report the same values, I'll move one of them in the children's bathroom where it's supposed to have the maximum humidity exposure. If reported humidity is high enough (>90%) I'll leave it there for 2 weeks then move it back together with other sensors and see if it got a shift in humidity measurement.
Typical display in Domoticz: very reproductible values between the 3 sensors.
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Sounds like a good experiment.
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So unfortunately when I started this test it was "dry" season so even in batchroom it didn't prove very conclusive.
Had problem with battery life also due to bad settings + power cuts. Limitless reconnection time before going to sleep was fatal with 4h+ power cuts :)Just reprogrammed them today and put them back in place, 2 @1MHz with CR2016 and 1 @8MHz with CR2025.
Rainy season is back and I have high humidity values on the 3 of them, 91% in bathroom right now so I should be able to run the test. -
These chargers are looking really good... Great job on this!
Has anyone used these garden lights? They look like they'd be ready to go as a PIR/multi-sensor considering there's already a AA holder and plenty of room under the lens. Maybe they could be tucked up by the ceiling. It wouldn't quite be flush because of the sloping top, but it may not be bad.
Searching around I see at least two different variations--one has a smoother, cleaner look to the lens and the other looks more "knobby." Some come with a battery and some do not.
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These chargers are looking really good... Great job on this!
Has anyone used these garden lights? They look like they'd be ready to go as a PIR/multi-sensor considering there's already a AA holder and plenty of room under the lens. Maybe they could be tucked up by the ceiling. It wouldn't quite be flush because of the sloping top, but it may not be bad.
Searching around I see at least two different variations--one has a smoother, cleaner look to the lens and the other looks more "knobby." Some come with a battery and some do not.
@hautomate well it doesn't look so great imho.
There's no space for PIR lens so you have to make one yourself, it looks like hard plastic and it won't be easy to drill without generating any cracks.
No holes to put other types of sensors like temperature/humidity/... so same problem. In addition if you put it under the sun to charge, the temperature inside will not allow any measurement of this type.
Charging circuit is primitive, it's probably the same IC than in the 1$ garden lights and it just puts voltage to the battery +/- without any control of voltage: not a good way to maintain a good health for the battery.So in the end you have a box that you need to modify to make it a sensor (except maybe a light sensor), you have a solar panel that provides a too low voltage so you need a step up converter, you have a charging circuit that's too bad to use and that in the end won't make the rechargeable battery last longer than 2 AA... Rather expensive for a plastic box :P
