Photomonitoring gear

[PatShaw]

In 1994 (yeah, I know...not just yesterday!), the Werkers had an article in the NSS News conservation issue which described and showed pictures of a sweet photomonitoring system. The article was very short, just one page, and didn't have a lot of details...like few beyond the couple of pictures.

I'd love to make a similar system and components and wondered a few things:

1) has anyone seen or used or have one of these systems? Maybe have some pictures of the business parts?
2) I've tried contacting Jim Werker using a couple of likely email addresses to see about any construction details, but no joy yet. Is anyone in contact with either Werker and could pass along this request?

That's it - fingers crossed!

Cheers,
Pat Shaw NSS15815

[KsCaver22]

Hi Pat -

I have been working on a cave intrusion detector. It is based on an Arduino microcontroller and a light sensor. It is intended to be placed in the dark zone of a cave. If it detects even a sliver of light, it records an event on a MicroSD memory card. A "sliver" means a few ten-thousandths of a lux. Yeah, it is very sensitive.

The entire device, batteries and all, fits in a 1 pound peanut butter jar. It runs for 6 or 7 months on a pair of 18650 rechargeable batteries.

Is this about what you have in mind? If so, contact me and I will send more details. bgee at campercaver.net

Bill Gee
NSS49528

[PatShaw]

Hi Bill,

That sounds quite cool. Years ago I (with much help from an electronics-savvy friend) made some caver-counters which were really just a photocell connected to a HOBO event logger...and appropriate cave-proofing. Quite small and easily hidden - it was difficult to get a real count since every pass of a light was a single increment, but great for getting an indication of traffic. Seems like the quick-fix compared to the system you've created. I hope some details of your Arduino system show up in something like the CREG Journal or another suitable place!

However, that's not at all what I was thinking though. The Werkers had a nice system for repeated photographs of a single scene to monitor any visible attribute ... colour, mud spread, broken stal ... whatever. There was a combo of a drilled hole with a glue-in insert and a monopod for the camera with a matching (and apparently locking) base to fit the inserts. It's a simple concept, but I'd sooner not reinvent the system in making one. Their article with pictures was in the NSS News, February 1994, Page 66.

Cheers,
Pat Shaw NSS15815

[KsCaver22]

Hi Pat -

I have only been an NSS member since 2001, so I don't have back issues to 1994.

It sounds like what you want is something similar to a trail or game camera. I think many of them can be programmed to take a photo at regular intervals. Lighting could be an issue as many of them do not have visible light flashes.

There are good camera modules for Raspberry Pi computers. Power and lighting would be the major issues. Raspberry Pi does not have any kind of sleep mode, so it eats power all the time. Even an automobile-size battery will run a Pi for only a few weeks.

Bill Gee

[chac]

Hi Pat,

I think Bill is correct in suggesting you look into game cameras. These are about the size of a book and incorporate highly responsive infrared motion sensors. The images are stored on a micro SD card and are of excellent quality. Being a game camera, they are suitable for the cave environment. Folks have used these in Quintana Roo dry caves for many years as a means to study jaguar use of the caves.

To retrieve the photographs, just replace the SD card and change the batteries. The camera will take pictures for quite a while depending on the amount of traffic that triggers the motion sensor. Temperature of the cave (cold or warm) will also affect battery life. If the cave is humid you can place small desiccant packages in the camera if you are changing the batteries or SD card in the cave.

I suggest you use a second camera in the same area that is shooting from a different angle. That is just in case one camera goes missing.

Have a look at Amazon for game cameras.

Jim

[PatShaw]

Hi Bill and Jim,

Thanks for the replies, but trail cameras are not at all what I need. As fun as they are! The 1994 NSS News issue where the Werker's article was published is included in the news archive. It's a system using glue-in locator sockets, a monopod to fit the sockets and a digital camera...which was a film camera when the article was published, of course! I have recently gotten in touch with the Werkers directly, and if I have any luck pulling the system together I'll post pictures.

Cheers!
Pat

[KsCaver22]

I went to the archive and downloaded the Feb 1994 issue of NSS News. Reading through the article by the Werkers, I now have a much better understanding of what they did. I still think a game camera is a better tool, unless there will be vandalism problems.

The basic objective is to get identical photos of a section of a cave over a period of months to years. The Werker's solution is to glue a camera mount into the cave so that a camera can be aimed exactly the same way over multiple trips. They do not leave the camera in the cave, and the photos are taken at irregular intervals which depend on how cave trips can be planned.

It is an interesting idea. It is cheap and fairly easy to implement. I see several possible problems. First, over the course of years camera technology changes. The Werker's system assumes you are using the same camera on every trip. If the camera changes, then it is much more difficult to compare the photos over time. They also assume you can duplicate the lighting on every trip. Last, there is an assumption that cave trips can be arranged at more or less regular intervals. That requires a team of dedicated project cavers along with a plan to hand off the project to new generations.

Most game cameras can be programmed to take a photo at regular intervals instead of depending on a motion sensor. Some research would be required to find one that can delay a month or more between photos. I suspect most of them want to take a photo every few minutes to perhaps once a day. You would also need to find one that uses a visible light flash. IR flash systems will probably not give you the kind of photos you want.

Some of the same problems still apply. The game camera has to be visited every now and then to retrieve the memory card and change the batteries. The built-in flash may not be suitable to light the subject area. I already mentioned possible vandalism problems.

Bill Gee