Burrowing Owl Relocation Sound Box

Gentlefolk, I just found this book ("Internet of Things Projects with ESP32") which I hope will help supplement your learned advice. I'm pretty good at math, but much better at learning by example. I will continue to take copious notes from this thread in order to refine my research.

In addition, I think that I ought to double check the idle power consumption of my sound player...which should be zero, but I'm not sure I ever checked. If the sound player sleeps restlessly, then its power consumption becomes constant C that has not been factored in.

@papajoe0418 If you control it with a MOSFET it will be zero. You want the sound generator on a separate battery, it's a bad idea to share power in this case.

Hi all @zander, @papajoe0418, @byron,

  First, an apology that I made a mistake. The ESP32 wake up timer is apparently 64-bit ... I looked up it the ESP8266, which according to the makers Espressif, is 32-bit ... and made the mistake of thinking ESP32 was the same ... Sorry for any confusion. In (pathetic) mitigation, I didn't see waking up once an hour as anything more than inconvenience, and I had the feeling that the ESP8266 was seen as a cheaper (and hence preferred alternative).

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I note the subsequent discussion about concern the sound module part may have a significant qiescent current draw ... and I think you will be very lucky if it is down to microAmp or two ... I would expect much higher than that, unless it has been specifically designed for a "micropower" application. I also suspect you may need to use a little cunning to measure a current that small.

However, it should be possible to use a MOSFET as a power switch to 'depower it' when it isn't needed. Providing the power draw whilst 'hooting' is reasonably modest, say under 100mA, then the three AAs you planned should be ok but don't forget to put some decoupling capacitors in appropriate places.

Also beware of the control connection(s) between your sound module and the ESP32 ... they are likely to need some form of level conversion.

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Also, the common ESP32 boards may present related issues.

The ESP32 is 3.3V (possibly 3.6V absolute max?) device, and is often provided with a regulator such as AM1117. A quick look at the data sheet http://www.advanced-monolithic.com/pdf/ds1117.pdf says

 and it also says

I am hoping (without evidence) the second is not too much of  problem, I suspect it is more important when external resistors are used to modify the putput voltage,  but the quiescent current is certainly a problem.

Low power regulators exist ... at least in data sheets, I haven't used any ... this is result of some quick Googling

e.g. MCP170x where x seems to be 1,2 or 3    e.g MCP1703

https://uk.farnell.com/microchip/mcp1703at-3302e-cb/ldo-2-7-16vin-0-25a-3-3v-2-3sot23/dp/2218573

Note this regulator is only 0.25A ... I hope this will be fine for hooting time control, but don't try things like WiFi and Bluetooth!

As for availability this century .... I'll leave that to you. 😀 

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Another thing to watch out for on the development boards is any USB conversion chips (CH2102, etc.) ... again not needed for hooter control, but probably not micropower friendly

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So if you start with a simple dev board ESP32, expect to do a little surgery, possibly including switchable options between programming and usage.

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And whilst I apologise for my error above, please note the rest of the message is purely from looking stuff up on the web, and may also have oversights, etc.

Best wishes, Dave

@davee @papajoe0418 I was just looking at the sound module PapaJoe provided a link for recently and I see it has a rechargeable Lithium battery as a power source (can be non-rechargeable also).

This just cries out to be Lithium + solar driven. Any drain on the battery at night will be made up by an 8" x 8" solar panel producing 5W. Now I would consider a single 3.7V 2000 mAh to power the entire setup either an 18650 or the much smaller 14500. Since an entire battery is roughly 7.4 Watts, a 5W solar panel needs less than 1.5 hours to fully charge the battery. Since the hooter and board will take many days to drain that battery, a few cloudy days is of no consequence. With a single 3.7V you will need a boost converter to get it to 5V then it just plugs into the sound board and the esp32 with standard micro USB plugs.

You can choose to build your own solar controller, or purchase an off the shelf solution. I am sure the internet can supply a diy solution to charge either 18650's or 14500's from a solar panel.

You will need to build the step up board, but I use LM2596 Buck/Boost modules for inside my RV as I have a 7,200 Watt hour 12V Solar UPS.

Thinking about this a bit more, 2 of the batteries in series gives 7.4V and that is a better fit using a buck converter to bring it down to 5V That 2 battery solution will run forever.

As a diversion from the pure numbers of this experiment, I've posted a short video of my first prototype device. Luckily, I've isolated batteries from microprocessor from sound player, each in its own separate project box. So when I re-tinker it for power optimization, it won't all be a jumble of wires and soldering points.

Enjoy!

lHi Ron @zander &  @papajoe0418 ,

   Ron, I may still have the 'spec' wrong, but my impression is that this is currently a small scale/feasibility study to see if owls actually "like" to be hooted at ... it is not a proven technique that to be rolled out on a large scale and for an extended period of time.

Hence, whilst your suggestion may have much technical merit, I suspect it is not approriate at this stage. Assuming @papajoe0418 can get the unit to function as desired, which is for a period of 1-4 weeks, on a set of 3 AA cells, isn't that good enough?

Of course, if I have got it wrong, then my apologies and please indicate accordingly .

Best wishes all, Dave

Posted by: @davee

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currently a small scale/feasibility study

This is precisely correct. A study to this effect was done by the San Diego Zoo Wildlife Alliance. I'm trying to replicate the results here in Arizona. No doubt the publicly funded alliance used expensive equipment to perform the study. If it works, our local organization could reap the benefit at substantially lower monetary investment. 😀 

@davee FYI @papajoe0418 You make a good point Dave, and hopefully, PapaJoe will let us know.

I guess he could defer the Lithium batteries, the solar panel, and maybe even the DS3231 RTC but he will need 2.6 to 3.6 Volts, 3 AA cells will be 4.5V well above the tolerance so the LM2596 is still needed. An alternative is 4 AA which can be used for VBAT or USB which allows 6V. The board will manage the 5V to 3.3V conversion. That is the easiest power supply concept.

One risky aspect to be avoided is if you have both Lithium and Non Lithium cells, make absolutely sure the two battery circuits are isolated as the Lithium will drain the other batteries. Of course, that arrangement precludes charging which is why for the long term a single rechargeable lithium makes the most sense.

Of course when/if he adds the DS3231 RTC to reduce the power drain the code will need to be rewritten but both cases are almost trivial.

Hi @zander & @papajoe0418, @byron,

  Ron, the data sheets suggest that an ESP32 could do all of the timing/control without needing an DSxxxx RTC, but I sure we all know that the 'unexpected' can appear when you try to do something that looks straightforward, so I would have at least one DS type RTC in the cupboard as part of a back up plan whilst doing the development phase.

The ESP32 would prefer 3.3V, certainly not more than 3.6v and I think the 'useful' minimum might be 3.0V, based on some memory chip requirements which  often get packaged under the familiar metal rectangular cover.

Given a principal power source of 3 x AA alkaline cells, the 'obvious' method of meeting this requirement is a 3.3V linear regulator, but some care is needed to pick one with low quiescient current .. the default usually fitted to development boards is probably unsuitable, but that should be easy to unsolder.

There are some 'unconventional' approaches that could also be suggested, of which the simplest is to power it from just two of the three cells. New alkaline cells typically produce 1.6V each, and keep above 1.5V for a fair proportion of their useful life, so this should mean an operating voltage of 3.0 to 3.2V, providing the cells are changed before they are completely exhausted.

Cross charging batteries is always a dangerous, particularly where lithium chemisty based cells are concerned, but obviously can only happen if their are any such cells. The hope is they can be eliminated.

Switch mode power supplies like LM2596 will take much more power than the control solutions we are considering.

The Pico has on onboard buck converter which has been specially designed for the purpose, making it much lower power consumption than general most general purpose buck regulators, but it is probably still the main reason why Pico's mimimum power consumption in 'sleep modes' is still much larger than say the ESP32 in its sleep modes.

DS3231 (or D1307) current drain should be insignificant in any realistic scenario.

Best wishes, Dave

@papajoe0418 

Probably off topic but the question that came to me was: Can the burrowing owl be bred in captivity? No need for fake hooting owls if you have enough real owls to do the hooting. Mice are easy to breed in large numbers. A large caged area like I have seen in zoos with lots of burrowing owls with water and seeds for the mice to eat.

Why haven't the burrowing owls moved by themselves to these areas where you are trying to establish a population? A lack of natural corridors?

As a child I spent a lot of time in the bush (mallee country) which was abundant with bird life. A few years ago the trees were mowed down and the land turned into a desert (for future development) and some of it irrigated and planted up with wine grapes. All those birds and animals are gone. Where did they go? Well there is only so much land and as we take it away from the animals there is no more land to provide them with food so they all died. There was no more land on which to reestablish their population otherwise they would have already spread to that land. The only survivors will be those animals able to live with humans.

@robotbuilder

Posted by: @robotbuilder

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Can the burrowing owl be bred in captivity?

Probably, yes. But this isn't captivity. It's relocation. Land development continues to deplete natural environment. By law (in AZ), we must relocate our owls beforehand. So what is done is that the resident owls are captured and tagged, then we build burrows in safe areas and attempt to "entice" the owls to relocate to those new burrows. Often, they fly off and (hopefully) find existing burrows elsewhere. In any event, we try.

As it turns out, in my area, there is a large community of burrowing owls. It's just not close to where we've built these new burrows. Owls don't build their own burrows. They use what's already there. So we can't even rely on the existing communities to "take in new residents" if all of the burrows are already occupied. Our five burrows are currently empty. 🙁 

I think that answers most of your questions. We could have just let the owls fly away and hope that they found something other than a hole in a berm. But we have a legal obligation to rehome them in the wild.

@davee @papajoe0418 @byron This old brain is having a lot of trouble keeping track of all the details. Is the esp32 in its lowest power mode able to wake itself? I thought it was relying on an external interrupt at that sleep level of HIBERNATION?

My understanding is that switching VR's like the LM2596 are much more efficient than linear regulators but maybe I am wrong. See pic1.

No point talking about PICO, it's DOA until they get the low power code stable.

I am bowing out of this Topic as Dave and I have major differences in design and I can only be 100% sure I am right if/when I build an equivalent project. That will take a few months depending on my health issues

Good luck.

@davee I have confirmed that the DS3231 is NOT needed with the esp32 unless an accurate clock is needed to determine when to do the hooting. The lowest level of sleep called hibernation is               5 microAmps and the onboard RTC still functions. You will lose memory retention across the sleep period so if that is needed then you need to go to deep sleep at 10 microAmps but if you have a DS3231 attached it can be the source of date and time if that is all that needs to be preserved.

Hi Ron @zander, (@papajoe0418 @byron )

  Hibernation would indeed not be helpful, as I think it closes virtually everything down .. but deep sleep looks more hopeful, as it leaves some timers and stuff going, whilst stopping the main processors.

  But the documentation is not the clearest, the common examples show a sleep of about 5 seconds, not hours to days, and there are some contradictory reports of the accuracy of the timer,  so a nasty problem could easily appear at any time - I certainly do not rule needing something like a DSxxxx rtc, but it is worth trying without one to start with.

This project is 'pushing' the boundary a lot further than anything I can find. The nearest 'real data' is @byron has posted his own experience, which was positive.

However, this is the all nature of research  ... you win some, you workaround some, and you lose some. Place your bets which this one will be!

I once heard someone say 90% of money spent on research is totally useless ... the tricky bit is no one can figure out which will be the useful 10% spend without spending the other 90%.

I don't know if 10%/90% is accurate ratio, but I think the underlying principle is fairly sound.

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As for efficiency of switch mode power supplies, you are right to consider they are more efficient than linear regulators when dealing with appreciable power levels .. certainly at the Watts and above level, and even down to say 10s of milliwatts, and sometimes down to milliWatts.

However down at the microwatts, the situation changes. A linear regulator is essentially a 'magic' resistor ... it reduces the voltage by inserting a dynamic resistance which drops just the right voltage ... and 'magic' is the resistance changes to compensate for changes with load, input voltage, etc.

Now obviously resistor can only drop a voltage by converting some of the power flow into heat ... which if your power levels are high, tends to mean lots of heat and poor efficiency.

By comparison, a switch mode power supply tries to be in one of two states ... full conduction (no resistance) or no conduction (infinite resistance), and the control system alternates between these two conditions so that 'just the right amount' of power flows through, when averaged over time. And, in theory, because there is never a time when current is flowing through a resistance, there isn't any power loss.

The downsides are that the switch mode is not perfect ... the switching action involves losses, particular on each transition, and also it requires a control circuit, typically a microprocessor to make it all happen.

So at the microwatts level, the linear regulators can be much more efficient.

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Best wishes, my friend, take care of yourself. Dave

Hi Ron @zander,

  Re esp32 unless an accurate clock is needed to determine when to do the hooting.  etc. etc.

Thanks for the confirmation .. nice to know I haven't made too many more obvious mistakes.

I am assuming the owls aren't going to be too fussy about the timing accuracy, so long as it doesn't conflict with the obvious day/night cycle ... so hopefully not more than (say) an hour drift over a maximum period of 4 weeks.

Whether the ESP32 can manage that is unclear, but I think the only one to find out maybe to try it.

Perhaps it is worth mentioning, I am assuming the 'schedule' of when to hoot, etc. will be 'programmed in', either as a table or an algorithm, and hence stored in the non volatile memory section. So, that each 'wake up' can be more like a reboot, albeit a 'warm' reboot, since some things like the inbuilt RTC musn't be reset, than a resumption of running program. 

Best wishes, Dave