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Post by SDL on May 27, 2021 13:48:19 GMT -8
Folks, I've been investigating a problem with one of our test units down in Palm Springs. And I've found something interesting. It went off line (actually, not off line - everything was still sending perfectly) but the AQI reading had gone to 0 and stayed there. I was coming down to Palm Springs (I know, tough duty) and so I brought a spare Laser AQI with me. After taking apart the box, I reset the power and the AQI started working again. So, there is a mode where the AQI sensor processor hangs. Hmmm. Even surviving the low power mode (I have that installed). Here's what I am going to do to the AQI code. I'm going to start looking at the AQI readings and if I get two readings in a row (over 15 minutes) I'm going to shut off the patting watchdog code, which means the system will reset in 200 seconds. I think that might get the AQI running again. I'll post the code on the repository when I get it done. John
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ncjay
Junior Member
Posts: 71
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Post by ncjay on Jun 1, 2021 14:29:51 GMT -8
I may be having this same problem. I have not yet disassembled and reassembled the unit.
When you say you reset the power - what did you do? Just unplugged the battery and solar array?
Thanks ncjay
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Post by doxidad on Jun 1, 2021 15:14:28 GMT -8
Just turn the switch off on the SubAirPlus card and turn it back on. This turns the power off to all the active components.
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ncjay
Junior Member
Posts: 71
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Post by ncjay on Jun 2, 2021 4:57:22 GMT -8
Thanks. I had tried that when I first noticed the problem, but with no change (i.e. the only LED that was lit was the Solar indicator, with the unit under my desk task light). But I just tried it again and all the appropriate LEDs lit, and it's back outside now happily collecting readings.
Looking forward to an eventual software update.
ncjay Wake Forest NC
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ncjay
Junior Member
Posts: 71
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Post by ncjay on Jun 2, 2021 6:57:29 GMT -8
...and on the next check: no updated readings, no LEDs illuminated except for the solar power indicator. It might have worked for 15 minutes or so. Power cycling didn't change anything this time.
I'm stumped here.
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Post by doxidad on Jun 2, 2021 7:13:16 GMT -8
Just a guess. Check your battery voltage. You need to have a minimum V to run (not sure what it is without looking it up). Your solar LED may be illuminated and it may be trying to charge the battery but there is not enough between solar + battery to run your Mini Pro Plus + AQI hardware.
If the battery is way low you may want to plug a charger into the SunAirPlus board - the mini USB connector for a few hours to get your battery charged back up. The Red LED on the SunAir board will be red when charging and will go out and the green led will light wen totally charged.
My battery V runs between 3.8 - 4.2V - I am not running the AQI but TB - but it is the same boards just different sensors.
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ncjay
Junior Member
Posts: 71
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Post by ncjay on Jun 2, 2021 12:46:36 GMT -8
This one is showing 5.1v (not under load), measured as the battery sits in the unit (i.e. I didn't tear it apart, I just tested at the points coming out of the battery connector receptacle). If that method would provide a bogus reading, please let me know. The battery is brand new - the newly-assembled sensor unit only worked a day or so before AQI dropped to 0 as @sdl encountered in the original post.
It's been five hours since I last tried to power it up - so I just did, and I got a full complement of LEDs illuminated. I'm keeping the unit right here next to me, under the desk task lamp, and only about three feet from the antenna. Looks like I got a single reading, then moments later the reported AQI dropped to 0, and now I only have the solar power LED lit again. There should be additional LEDs lit during normal operation, right?
Guess I'll patiently wait for @sdl to weigh in here.
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Post by doxidad on Jun 2, 2021 16:11:03 GMT -8
There should be a blue LED on the MiniProPlus. If it's not lit, you're not getting power or enough power to it.
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ncjay
Junior Member
Posts: 71
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Post by ncjay on Jun 3, 2021 5:28:39 GMT -8
As I suspected, thanks. When there's power things are fine, but something is shutting down the sensor and (hence) shutting off the blue LED.
It's been powered down for 16 hours now. I just turned it on, and - there's the blue LED! And after a minute - it's out again. It transmitted one reading: AQI 0, load voltage 5.0, battery voltage about 2.8 (?), battery current 225 {units}, load current about 80 {units}.
It appears the sensor is shutting down even before the solar panel has a chance to charge the battery....?
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Post by doxidad on Jun 3, 2021 7:33:23 GMT -8
The 2.8V is the problem. Have you tried to charge the battery through a USB charger connected to the Sun Air board (turn off the power on the Sun Air board and charge through the mini USB port till the the green LED lights). You may read 5v on the battery but when under load it may have enough current to run things.
Charging the battery to full capacity will give you somewhere to start from. If it is fully charged and then dies quickly after turning on the system then we could assume there is a problem with the battery or one of the components in your setup.
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ncjay
Junior Member
Posts: 71
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Post by ncjay on Jun 3, 2021 16:03:10 GMT -8
Sounds good, thanks. Charging it now.
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Post by SDL on Jun 5, 2021 7:07:41 GMT -8
Your issues and data all fit my model of the problem. Working on a solution now.
John
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ncjay
Junior Member
Posts: 71
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Post by ncjay on Jun 6, 2021 12:33:35 GMT -8
Well, it turns out that doxidad put me on the right track, at least for my situation: the battery I was using had an insufficient charge. Weird because I bought two batteries - one for this unit and one for the Lightning sensor - and only this one had the problem. Thanks, doxidad! It took about 20 hours of USB charging for the green LED to come on. That was right before my temporary location ran out of sunlight yesterday, and the battery voltage decreased from 4.14 to 3.86v overnight. It hasn't charged past that, but we're at 3.85v now (and we're out of direct sunlight again). We'll see what happens overnight tonight, then I'll try to move it to my preferred location tomorrow, near the WeatherRack2. It still remains to be seen if the 433MHz transmitter can push a signal to my receiver antenna from there, though (ref. my Lightning Sensor thread). Still looking forward to the eventual software update, though. Thanks for keeping it under active development. ncjay Wake Forest NC
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Post by SDL on Jun 6, 2021 15:48:42 GMT -8
mckay,
Yes, your data fits my hypothesis. Yes, definitely under active development. If I am correct in my theory, this affects AQ, Lightning and AfterShock.
John
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Post by SDL on Jun 9, 2021 16:05:55 GMT -8
Folks, I've analyzed the situation and have a couple of solutions. Can't do it in software, unfortunately! Need a hardware fix. If the battery gets too low (about 2.8V) and the solar conditions are just right (not a ton of sun) then the charge controller decides (rightly so) to just trickle charge the battery, which is the right way to recover a heavily discharged LiPo battery. The problem is that the MiniProPlus with the peripherals can draw the entire trickle charge (especially the AQI. Lightning and AfterShock not so much) and then the controller never gets out of the trickle charge. As soon as it does, the Mini Pro Plus and peripherals can draw a lot of power (with the load voltage now at 5V) and in the right conditions it will take the battery right back down to the trickle charge stage. We addressed this with SkyWeather2, SolarMAX2 and others, but because of the vastly lower current draw of the WeatherSense units, we felt good about our testing. Whoops! We were wrong. Well, kind of wrong. I've seen this in the Palm Springs systems (where the system recovers properly because of the really bright sun!) and in units here in Washington State. During testing, we did the deep discharge and the systems did recover. But now I have discovered there is a set of conditions that might take a long time or never to recover. We call this solar power system "battery chatter". Bang, bang goes the voltage up and down and the controller follows right along! Good news is your LiPo batteries are properly protected. That will kill a Raspberry Pi, but the Mini Pro Plus is essentially totally resistant to this problem. The work around for this problem is to charge your battery up through the USB port on the SunAirPlus2 board. That gets your system up and running. The solution to this problem is to install a hysteresis circuit that will turn the battery off at around ~3.1V (thus avoiding the trickle charge state) and back on again when the battery reaches ~3.7V and is in full charge mode. This is what we do with the bigger systems. We have figured how to fix this and offer two solutions, one short term and one long term. 1) You can install a USB PowerControl or USB PowerCentral between the SunAirPlus board and the Mini Pro Plus and connect a single jumper wire from Battery + (JP4) on the SunAirPlus2 board to the LIPOBATIN on the USB PowerControl or PowerCentral boards. This solution does not fit easily in the 3D Printed box, but with some adaptor cables you can make it work. PM me for a $10 off coupon for either of those boards. Picture attached. This correctly implements the hysteresis solution and everything will work well. I know, not a perfect solution, but for those sets of systems in the low solar power areas, this will work. shop.switchdoc.com/products/usb-powercontrol-board-v2-w-grove-control-usb-to-usb-solid-state-relay-for-raspberry-pi-and-arduinos-v2shop.switchdoc.com/products/copy-of-usb-powercontrol-board-v2-w-grove-control-usb-to-usb-solid-state-relay-for-raspberry-pi-and-arduinos-v2These are cool boards that have a lot of other uses also. 2) We just submitted a new board, SunAirPlus3, to our manufacturer. We have added a hysteresis circuit on the board that will shut off the power to the MiniPro Plus and peripherals (3.1V and 3.7V). This fixes the problem correctly also but will not be available for around 10 weeks or so. When this board comes out, we will give a big coupon (don't know the pricing yet) for those people that want to avoid this rare condition. This will be an expensive board (like SunAirPlus), but we will do what we can. Thanks for all your help in giving me data from your system that supported my engineering study, that resulted in identifying and correcting this rare problem! Best regards, and thanks again! John C. Shovic, PhD CTO SwitchDoc Labs
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