hello.

16 Jan 09

Big generator still out today so we’re still operating on the small one. Conserving power, and no internet this morning. Running on battery power as long as I can.

Proxmity Tracking paper

Reading the proximity paper I mentioned a few days ago. A few interesting things stick out:

The collars had a weight of 125g. That’s too high for us. Are they less now?

The error rates look high to me. In the field, 34% exhibited problems they could not correct in the field. Apparently this is similar to the rates for GPS collars. Given my own experience with small GPS units, I wonder if that’s due to the size of the GPS collar. In any event, a 34% failure rate for proximity collars seems high.

The number of erroneous contacts is worth noting. Below a 15-second sample rate, they saw many continuous contacts show up as multiple contacts. That’s not so useful, though they do note that as the sample rate is taken higher, the number of erroneous multiple contacts decreases.

The number of “phantom radio detections” they had seems high too. I wonder if they are all analog radios, which is what’s causing the error?

They state that “because this was the first field deployment of these collars, such problems were not unexpected and determining their causes should enhance design modifications to limit similar problems.” In other words, they might be functioning much better now. This paper is from 2006, meaning there’s likely been another revision or two of the collars.

Their tests were all for the 1 – 1.5m range, though the collars can supposedly go out to 100m. I wonder if any research has been done on the longer ranges.

Further research: “Passive integrated transponder (PIT) tags have been used successfully to monitor individuals’ proximity to structures or use of certain areas (Prentice et al. 1990, Harper and Batzli 1996, Boarman et al. 1998, Kunz 2001, Gibbons and Andrews 2004) but have not been used to document individual-to-individual contacts. To our knowledge, the only previous attempt at proximity detection has been the MateID system (Sirtrack Ltd.; Ji et al. 1999, 2005)….. This system is limited in that contact can be estimated between, but not within, the 2 groups (e.g., genders) and only at very close ranges.”

“One-way systems may be available in the future, utilizing fixed-location receivers and animals carrying only transmitters, which would be similar to some current PIT tag applications (Gibbons and Andrews 2004). Such an arrangement would have positive implications for power consumption and collar size.” It would also have positive implications for our relay idea.

The rest of the day

In other news, it was a fairly quiet day. After a morning reading up on animal telemetry, we had a nice small lunch — only two tables out of about twelve were filled, because it’s Friday, and the boat took the last large group of undergrads back up the river after breakfast this morning. We had a leisurely lunch, filled with stories from Rudy the ornithologist about his travels around Bolivia, the hallucinogenic effects of ayahuasca and San Pedro cactus, and so forth.

After lunch, I finished off a little code and some email, then went for a walk on my own. It was a gorgeous sunny day, and the view from the canopy tower was spectacular. Lots of butterflies, but sadly, no monkeys. Then, on the way back, I ran across a group of wooly monkeys and got the chance to take some more pictures. Finally got a half decent one of a monkey staring down at me while he wrestles with another monkey. Those little bastards are hard to get pictures of!

Came back to camp and coded a little more, then did a quick run into the forest with Tony and Margaret looking for a wooly group she had been tracking earlier in the day. We didn’t find them, unfortunately. There is some confusion at the moment as to which monkeys are in which groups, because both Margaret and Peter have run across at least two signals at the same time. Tony’s not sure what it means, but he’s intrigued.

A new batch of undergrads have arrived this afternoon. We’ll see what they’re like at dinner.

13 Jan 2009

Question: what are the regulations on long-range 2.4GHz and associated bands in this area?

25-30 animals in a group typically, although spider monkeys typically move in smaller groups ( less than 5-6?)

Didn’t go into the field today, stayed in to read up on wildlife telemetry.  Found an interesting product from Sirtrack that already does proximity detection. These collars have to be retrieved from the field, though. It’s not clear from the Sirtrack site what the range on the collars is, but there’s a decent paper on them:  New Radiocollars for the Detection of Proximity among Individuals, by Suzanne Prange, Trevor Jordan, Colin Hunter and Stanley D. Gehrt in the Wildlife Society Bulletin, Vol. 34, No. 5 (Dec., 2006), pp. 1333-1344 Published by: Allen Press. I think these are worth some experimentation. I started to work up a simulation of what we might do with them in Processing.

Today is laundry day, oh joy.  Clean clothes tomorrow.

The rain last night was very intense at two points, strongest I’ve heard other than a hurricane or nor’easter.  No wind, though, which probably made it all the more intense.  There’s been much more rain than everyone expects (this being the dry season), so most everyone’s tracking is less productive than they’d like.  The dragonfly researchers (Rosser and Nataliya) have found only half the species they expected to so far, and spend much of their time in camp because it’s just not worth going out, for them.  The monkey folks go out most of the time, though.
A typical day around here for most of the researchers looks like this:
6:30 AM breakfast. 7 – 7:30ish prep for fieldwork. Most of the morning is spent in the field.  Some come back for lunch at noon, others take lunch and keep going. Afternoon is more fieldwork until about 5 or 5:30, followed by checkin at the lab, shower, and dinner at 7.  Most head back to the lab after dinner (8ish) and work until the electricity goes off at 9:30.  Then bed. By then it’s very dark, and you’re going to be up early, so you might as well go to sleep. Sometimes people head out earlier.  For example, I’ve seen Tony’s team head out at 5:45 some mornings to get to the monkeys earlier.

Electricity is on twice a day, from 10:30 until about 1 I think, and 6 or 6:30 until 9:30.  In the labs, the power comes on earlier, about 8:15 AM, and stays on later.  The network connection is up from about 8:30 until 9:30 in the labs, when it’s working.   There’s no media that I’ve noticed: no TV, haven’t heard any radio.

The showers are cold, but after a hike they’re refreshing once you get past the initial shock.  The cabins are all open to the air (curtained and screened, but that’s it), so you’ve got a pretty good idea what everyone else is saying in your group of cabins, and can hear the forest all night.  It’s a rich soundscape, and pretty loud, I’ll try to record it one night.

In addition to the researchers, there are a number of school groups that come through.  All the ones I’ve noticed so far are undergrads from the US, on biology fieldtrips.  They’re typically in the field all day, and have night classes after dinner.

There are ants crawling across my screen as I sit here programming.

Camera Traps

Tony brought two camera traps back in from the field today. One’s a video camera trap and the other’s a still camera trap. They’re about the simplest things I’ve seen so far, it’d be easy to build them from scratch.  The video camera trap is just a Sony Handycam in a Pelican case attached to a microcontroller.  The microcontroller’s got a PIR motion sensor in it, and a photocell.  The photocell is there to tell if it’s day or night.  The PIR, of course, is for motion detection, and when it detects motion, the microcontroller sends a signal to the camera using the Sony LANC protocol.  There are a series of DIP switches on the back of the controller board to set the operating mode, and tuning potentiometers to adjust the sensitivity of the sensors.  Couldn’t get a look at the controller, but it looks like an 18-pin PIC. There’s also an IR LED array attached to the front, but they don’t use it since the monkeys aren’t nocturnal.  The still camera trap is about the same thing, except it’s using a different protocol for the different camera, also a Sony (PSC41).  The controller on that one is a little fancier in that they incorporated an LCD display for feedback about the operating modes.  I took some pictures which I’ll post on Flickr when I get home.

One thing that fascinates me about the gear they’re using in the field is how old the battery technology is.  Most of it relies on AA, C, or 9-volts. Seems like converting the stuff to something with a higher energy density, or easier recharging, would be an easy first step. Even some of the new equipment I read up on was using C cells.

12 Jan 2009

It’s getting a little easier here, for a few reasons. My stomach is getting stabler (still a ways to go), Tony and co. are only taking me on short baby walks. In fact, it’s quite a pleasant day today.

Have to consider rain in every component. There is always rain.

Everyone’s asked for photos. Here are the largest I can upload at the moment, more to come when I get home.

These monkeys are not in the station.  They’re at the resort where we waited for the boat the first time.  I don’t think they’re legal pets, though. I haven’t gotten any pictures of monkeys in the wild yet, because we’re usually on the move (because they’re on the move) and because I am way clumsy in the forest, and likely to throw the camera in the river and end up on my butt.

We learned something interesting today though:  my camera (Nikon D70) emits RF noise that interferes pretty heavily with the telemetry units.

I love this tree.  It’s huge.  One of the canopy towers is in this tree, about 35 meters up.

And here’s the money shots for the geeks:

This was taken from the top of the tree:

This morning, Kevin and Tony and I went to look for titi monkeys. We didn’t find any, but we did manage to get lost, or as Tony prefers to put it, “got to know the forest a little better.” It was a good hike, but frustrating for them because no monkeys were found. I did another test with the GPS micro-mini, and got the same results. I’m pretty sure it’s going to take a bigger antenna to make it work.

This afternoon, we ran some tests of signal strength of 2.4GHz using XBee radios. Transmitter was sending 1 sample of AD0 and AD1 at 80 ms intervals for all tests. I don’t necessarily want to use XBees, but they were the only high frequency radios I had in hand to test with. The current telemetry gear works in the 148 – 152MHz range, which supposedly gives better penetration through the foliage. Details below.

Tonight we’re in the lab seeing if we can get high by putting a mixture of momnkey poop and ethanol in the dry box to evaporate the solution. This is what happens when there’s not a lot of entertainment. We’re eager to see what happens.

Vertical tests

Test 1: I climbed from the top of canopy tower 1 to bottom (approx 35m). Used an Xbee as transmitter (chip antenna) and an Xbee as receiver (chip antenna). Got inconsistent signal from top to bottom, but consistent at about 25-30m on down. I climbed from the bottom of canopy tower 1 to top (approx 35m), while Anthony waited at the base. I stayed at the top for a minute or two.using an Xbee pro as transmitter (wire antenna) and an Xbee as receiver (chip antenna). Got good signal from top to bottom. -85dB at approx 35m.

Test 2: I climbed from the top of canopy tower 1 to bottom (approx 35m). Used an Xbee as transmitter (chip antenna) and an Xbee as receiver (chip antenna). Got inconsistent signal from top to bottom, but consistent at about 25-30m on down. -94dB at approx 25 – 30m.

Horizontal tests

Test 3: I stayed at the base of tower 1 with a transmitting radio while Anthony walked into the forest. He got lost and walked back, then walked out again (The second rise shows his return) Using an Xbee pro as transmitter (wire antenna) and an Xbee as receiver (chip antenna). Continued to get successful transmission out to approx. 60m. There is a sharp dropoff in signal strength, of 20 – 30dB, when he crossed into the trees and out of the clearing.

Test 4: I stayed at the base of tower 1 with a transmitting radio while Anthony walked back to me from the forest (approx 60m). Using an Xbee as transmitter (chip antenna) and an Xbee as receiver (chip antenna). There is a sharp dropoff in signal strength, of 20 – 30dB, when he crossed into the trees and out of the clearing. Signal consistent from about 45m, and gained strength more or less consistently all the way back. There are dips and spikes as he went, possibly due to the thickness of foliage?

Test 5: Using an XBee Pro as transmitter, the receiver walked as far away as he still had signal, then walked in and out of range at the periphery of the range. A noticeable dropoff when he went into the forest, but consistently increased on his return.

Tony mentioned that they don’t always use GPS because the trails and the trees are so well marked and well known that sometimes it’s more accurate to reference your position by the tree than by lat/long

Some weight limits to consider: We can probably go up to 100 grams on a large monkey. Here are the weights of the things we’ve currently got. Small monkey radios: currently 54g (big one), 22g (small one), large monkeys currently 45g. Logomatic v2 plus battery: 51g. Xbee Pro plus LilyPad power supply plus small LiPoly battery: 27g.

11 Jan 2009

Not much to say about today. I spent the whole day in camp, and much of it in the bathroom, getting intimate with the local microflora.

The researchers use dictaphones to record vocal notes on their observations. My first question was why not use the PDAs (model Palm Z22) to record vocal notes as well as the written notes?  Tony pointed out that the dictaphones are very small and easy to hold up to your mouth to speak into quietly, whereas the PDAs are not, particularly when they are in a dry bag.

Another item that could be handy: Coaxial cable repair kit. The coax cables that attach the telemetry antenna to the base unit go bad a lot.  Repair would save money on new cables.

We did a very slapdash test of the XBee radios in the forest today. I was hoping to see what kind of penetration we can get out of 2.4GHz radios in the forest. I put a receiver radio (XBee series 1 radio as a receiver) on a datalogger, and a second radio (XBee series 1 pro as a sender) on an accelerometer.  The received signal strength was surprisingly noisy considering that the distance between them was relatively constant.  We could see a clear dropoff, though, when he climbed the canopy tower. Will do more rigorous signal strength tests later on, I hope.