Clean looking sensor node
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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
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Also, at least based on my experience with cheap Chinese solar garden lights, the battery connections (and probably a lot of other parts too) will rapidly corrode/rust and fail soon after. Sorry if that sounds negative, but I see nothing to suggest otherwise in this instance. So, if you do decide to try it anyway, I suggest you try just one and see how it handles your weather first.
That said, my wife bought some solar garden lights at Costco earlier in the year, at about $8 each, and so far they're holding up and are working very well.
However, in that case, you've got an institutional buyer (Costco) with an interest in quality handling the due diligence on build quality and with a very generous and easy return policy. On Aliexpress, that just doesn't exist. -
@hautomate well it doesn't look so great imho.
There's no space for PIR lens so you have to make one yourself, it looks like hard plastic and it won't be easy to drill without generating any cracks.
No holes to put other types of sensors like temperature/humidity/... so same problem. In addition if you put it under the sun to charge, the temperature inside will not allow any measurement of this type.
Charging circuit is primitive, it's probably the same IC than in the 1$ 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
Yeah, I hear ya...
I'm thinking indoor use here and not using the solar panel or circuitry for anything--just use the plastic and lens and pack it with PIR and temp/humidity. Mounted up high on a wall, any holes could be drilled on the top as that side wouldn't be seen.
I'm going to try one out...
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Finding things to make into cases is fun. Here is my raspberry pi.
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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.
@nca78 said in Clean looking sensor node:
Typical display in Domoticz: very reproductible values between the 3 sensors.
So some follow up on the sensors comparison. I'm still using the same sensors, unfortunately my son threw his behind (I think) his wardrobe so I cannot access it. But I put the 2 others side by side in the fridge, waited 20 minutes after closing the door and after 3 years of use they are still impressively consistent !
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And after getting out of the fridge, side by side, only a reasonable difference in humidity level. ( and yes, the weather is unconfortable today :sweat_smile: )
