Maybe we should have started 20 years ago when hedgehogs were common here. I'm confident we don't/won't have a resident in our box, because we would have seen the usual evidence dotted around the garden during autumn if there had been any around......that's similar to how I started nearly 20 years ago...
-X- Counting the comings and goings. You would be counting visitors while the "hogs" are hibernating.I am now at a loss about how to tell when it is occupied.
Totally off the wall thought, since just about everything else has been proposed. Gas sensors. There are cheap electrochemical sensors for lot's of stuff. CO2, O2, ethanol, methanol, formaldehyde, hydrogen sulfide, etc., etc. Do hybernating hedgehogs, um, pass wind? Any other odd physiological emissions? Hybernating bears sweat phenol compounds, and stink.Having recently purchased a hedgehog hibernation box, and mounted it in the garden, I am now at a loss about how to tell when it is occupied. Initial thoughts about installing a PICAXE based wireless telemetry unit drew a blank when I realised that during hibernation hedgehogs drop their temperature to match the ambient environment and only rarely wake up and move about during the winter. What then to monitor?
I would therefore welcome any ideas for a non-invasive approach to detect whether a hedgehog box is occupied. Thanks.
who said that had to be reason other than why the hell not.I often find reason an inadequate tool.
Thanks Tex, very good summary of the suggested technique and reasons why they probably would not work. Quite like the latest idea about using an electronic nose but would imagine there would be quite a complex mix of fumes in the den (decomposing vegetation ext).Thanks, Bear. That makes a difference.
The original request is still unresolved.
-X- Counting the comings and goings. You would be counting visitors while the "hogs" are hibernating.
-X- Weight by cell or switch. They pack so much in that the space would be always compressed.
-X- Light. Too much junk in the space.
-X- Temperature. Hibernation means "no" relative temperature.
-X- Sound. They stop making noise while hibernated.
-X- Photos of naked female "hogs". Temperature might now work, but for only half the population. ... Well, mostly half.
-X- XRAY. Probably cause mutant "hogs" in the future. PICAXE doesn't have the power to analyze films.
-X- Eddy current. "Hogs" are non-ferrous.
Here's a thought. Don't laugh. At least not out loud.
Since the critters want to build a home in the box by bringing in other material and make their own space, could you pre-form the space for them so they wouldn't bring in "stuff?" I'm imagining Styrofoam cutout areas within the walls of the box with a path to each "home."
Then you have a place for sensors within the Styrofoam.
OK, BB, you're getting red in the face from holding in your laughter.
Totally fascinating in all respects. But tell me, do you have problems with visiting badgers? I own a small wood and hedgehogs were often to be sighted. Then badgers built a sett in a neighbour's garden (all the gardens are rather large around here) and we watched the demise of the hedgehogs...literally! Badgers are the one predator that can open a rolled up hedgehog. My niece and nephew used to come back from walking the wood with what they referred to as "hedgehog shells" - all that remained after the badger had partly unrolled the hedgehog and eaten it from the inside to the out. Badgers are increasing rather too successfully in the UK at the moment and one theory is that this increase is inversely proportional to the hedgehog population.I'm sure everyone knew you were only kidding.
Hogs are very much in focus in the UK at the moment. Unfortunately, this is because of their rapid decline in numbers. It is believed that there are only one million of them left. Although not yet on the official endangered list, I doubt it will be long before they are. In the sixties and seventies, almost every domestic household with a garden shed had a hog living under it. More recently, hardly any households have seen one. We have done several presentations at local schools and hardly any of the kids have ever seen one, which is really rather sad.
We loan out footprint tunnels and trail cameras to interested parties to see if they have any hog (or other) activity in their gardens. It was amazing how much uptake there was on this and we still have a waiting list.
Hibernation box occupancy is not as simple as it sounds which is why my current endeavours are based around RFID but even if your hogs have been chipped (obviously, only those that have visited the vet are) it is still far from job done. Just putting a scanner on the side of the box does not work. The hog must actually pass through the coil. I've been in contact with a RFID manufacturer and they have produced an "extra sensitive" version but even that struggles to get through the layers of a damp nest to the chip inside the hog. (and yes, it is driven by a PICAXE for the ID decode and data logging with "send text on activity" soon to be added.)
Meanwhile, keep the ideas coming. This is of national interest, not just us guys! Experts up and down the country have been asking the very same question.
The more I thought about this, the more I like your capacitance method, vs. my chemical sniffer approach. I know that it is possible for the Picaxe "touch" routine to be exquisitely sensitive (8 inch detection range) and with thought it can be made self calibrating. Perhaps a hybernation box with a grounded metal plate floor, and a metal plate internal roof connected to a "touch" pin could work. I've actually held a hedgehog. It's a spiny little beast roughly the size of my closed fist. But it's a water filled animal, and assuming (dangerous, I know) that the nesting material it drags in is relatively dry, it should give a pretty hefty capacitance effect when sleeping between two capacitor plates. Even if the plates are stuffed with dry leaves and grass.I'm liking the LIGO method, I was just having a conversation with a physicist friend about gravity waves, for years I thought gravity acted immediately was surprised to find out it propagates in waves like everything else.
I will read up about the sensor I linked, for some reason I thought that it could be made to work with motionless objects as a range finder tho the doppler method is the prefered.
I'm not sure how the more sophisticated wall stud sensors work, I know that most use capacitive method of detecting a stud but there was an innovation to use radar technology for detection, could be another venue to try.
I do like using a WiFi or bluetooth transmitter for detection, very elegant.
Strictly speaking you don't have to generate microwaves. Anything (or creature) containing water emits microwaves, and you can use this radiation to determine temperature in a completely passive way....However, a "microwave" solution just might be possible...
I made a quick mock up with two 7 cm aluminum plate squares feeding an 08M2 touch pin C.2. It's very sensitive, detected my hand with ease and to test it I also placed a small block of maple between the plates and it certainly detected that as well. I did notice that my fluorescent desk lamp had a massive effect but since the box will be sitting outside i would think interference would be minimal.I know that it is possible for the Picaxe "touch" routine to be exquisitely sensitive (8 inch detection range) and with thought it can be made self calibrating. Perhaps a hybernation box with a grounded metal plate floor, and a metal plate internal roof connected to a "touch" pin could work.
I think the theremin/touch pin technique is looking the most promising at the moment but changes in humidity may cause measurement issues. However, provided I look for relative changes (rather than a absolute trigger value) this approach might just work. If only I could find a cooperative hedgehog to conduct some preliminary tests.
Good example of lateral thinking but, based on the comments about hedgehog's personal hygiene, I still think its a task best done as remotely as possible.You could just have a look in the hide
Sorry, after all the negative feedback I just lost the will to go on. I hope you make better progress.Hi,
I stumbled on this thread whilst researching the same subject - wanting to monitor a new hedgehog box.
Good discussion which seemed to cover and reject all the ideas I'd considered and more.
Hence I'm bumping the thread to see what progress there might have been since 2015.
Cheers,
Kelvin