The Most Beautiful Spot in Costa Rica


Today was such a great day! We went on a hike and found the most beautiful spot in Costa Rica.

The morning began bright and early at 7am. We had breakfast at the lodge and hopped into the car to head to the base of the volcano we would be hiking up. Just before jumping into the car we found our first lizard of the day! It was bright green and Prof Clark was able to grab it to get a better look.

This is where we initially found the lizard.
Can you find the lizard on the tree?
Can you find the lizard on the tree?
Prof Clark holding the lizard.

The hike was a two kilometer trek with a lake at the end. Unfortunately it was steeply uphill the entire way, but we all made it. Along the way, we found three lizards, one butterfly, one frog, and one giant spider. That we got pictures of that is. 🙂

Lizard number one found by Prof Clark on the way up.
Butterfly found by Emily and Nick on the way up.
Frog found by Nick on the way up.
Basilisk found by Prof Clark on the way down.
Big spider found by Don on the way down. Can you spot it?
Lizard found by Nick on the way down. Look closely.

After the two hour hike to the top, we stopped by the viewing area to take a look the volcano. It was stunning.

The view of the volcano from the top of the other volcano.

Next, we descended the last hundred meters to reach the Green Lake. It lived up to its name! It was definitely green and cold. We had all either brought or wore our suites so we went for a quick swim. Nick and Prof Clark actually swam across the entire lake. It was decently impressive, at least to me.

The Green Lake

It was all downhill from there! However, there were still some spectacular views.

The view from just outside of the forest looking out.
The view from just outside of the forest looking at the way up.

Luckily food was not far from the end of the trail. We ate lunch at the hotel where we got more than we thought we ordered. For example, Don thought he was just ordering a drink for himself when, apparently, he had ordered it for the whole table. Plantains, limes, and ice cream magically appeared, too! It was great and very much needed. We were able to hop in the hotel  pool before heading back to work on sensors.

Sensor work was the same as usual. We got the Ph sensor working by rewiring and fixing the soldering on the PCB. The CO2 sensor got its final connections epoxed after all other options were explored.

After some good quality sensor work, we skipped out to head to dinner and to follow Don to a free hot spring. The hot spring was a bit off the beaten track and under a cement bridge that was obviously not meant for tourist eyes. However, the water was beautiful! It was so warm and the current was so much fun. It almost pulled me down stream multiple times! It is so hard to describe just how beautiful this spot was. After the freezing cold Green Lake, the steaming hot spring was incredible.

Akhil and Prof Clark in the hot spring.
Nick and Prof Clark in the hot spring.
All of us in the hot spring falling over. 🙂

Today was incredible! There is no doubt. Akhil went on his first hike and we got to relax in the steaming hot spring. Can’t wait for another day!



ROV testing hotel style

We got to test out the ROV and the CO2 sensor in the Holiday inn pool on Sunday morning. We had trouble finding an outlet outdoors, so we had to drive the ROV from a hallway inside of the hotel. It was a lot of fun zipping it around the small pool, and Emily was able to breach the ROV.

ROV Breach

Akhil Rov

Nick ROV

Our CO2 sensor tests on the other hand, did not fair so well. The sensor kept giving us the same value regardless of what condition we put the sensor in. we ran out of time before we could figure out what was wrong, and decided that we would work on it again later that night. We then drove to the hotel that we would be staying at for the next couple nights. It is amazing. This is the view from outside of the room:

Hotel Room

We also found our towels nicely arranged when we got into our room:


After getting something to eat we began working on debugging the CO2 sensor, and were ultimately able to figure out that our issues were due to a small coding error. After another long night working we are excited to get a day of rest exploring the area around the Arenal volcano.

Our First Day in Costa Rica

Saturday started with a very early morning. We met at the lab at 7:30am to double check that everything was packed before we left for Costa Rica. We decided to bring along the ROV because the AUV has been held up in customs for the past couple days. As we were leaving the lab, we noticed that the very thin Teflon tubing, which acts as the membrane for our CO2 sensor, had snapped at one of the joints! We did not have enough time to try to fix it then so we just had to pack it and worry about it later.  We landed in Costa Rica at 9:00pm local time and went out to get a quick bite to eat before we started working on the sensors. Image We worked late into the night to get the CO2 sensor running, and we were able to get it into a working state before the end of the night. We are excited for our field test in the Holiday Inn pool tomorrow where we will test the complete CO2 setup and drive the ROV for the first time.

Sensor Developments

We have been working super hard on completing our CO2 sensor over the last week or so. Once we designed the circuitry and tested it successfully on a bread board, we soldered it on to a PCB. Here’s what the final PCB looks like:Image

In case you’re wondering, the golden box-like structure on the left of the PCB is the CO2 analyzer. It shines an infrared light and measures how much the intensity of the beam falls in order to calculate the amount of CO2 in the analyzer. 

Once we made sure the circuitry was working fine, we started building the physical setup on which we would mount the sensor. To do this, we hit the Mudd machine shop and started battling with the 3D printer. 


After hours of battling, we emerged victorious and the printer gave us the following part on which we are going to mount the membrane which separates dissolved gases from the surrounding waters of the lakes.


After all of this, we tested for 2 things. First, if our physical setup leaked at all. We did this by dunking our work into a sink full of water and then checking the inside of the PVC (where we are going to mount all our circuitry) if any water had collected. Second, we checked if the sensor was still working fine after being integrated with the newly constructed parts. On both counts, we were good after some back and forth trouble shooting. 

Next feat — actually calibrate this sensor. Currently, it displays trends in CO2 rise and fall, but it doesn’t give us sensible numerical representations of the CO2 concentration in the room. Watch out for the next blog to hear about our calibration adventures!


Mission Two: Diving into Trouble

Hello all!

One week after the successful surface mission we went back to the Bernard Field Station to run a dive test. Unfortunately, it was a little less successful as in we temporarily misplaced the Iver in the bottom of the lake. But don’t worry! It was, in fact, temporary.

The trip started off the same way. Jerry and Yukun joined us and we took the Iver across campus in the college’s van. However, this time we had an acoustic shark tracking tag and weights that we attached to the Iver to track it if we lost it and to allow it to dive.

We went out in the boat, got the Iver pointed in the right directions, and pressed go on the mission. It went out, dived as expected, and didn’t come up. After a panicked 10 minutes, Jerry, Yukun, and Nick headed back to campus to retrieve the hydrophone to listen for the tag and to pick up Nick’s snorkeling equipment. Akhil and I waited by the lake hoping the Iver would just pop up. It didn’t.

Nick getting on his gear.

We tracked the Iver to a corner of the lake near its last turning point. It looked like it got stuck in the muddy overhang near the edge. Nick dived for it but couldn’t see it anywhere. The water was quite cold so we called Professor Clark and headed out. We made plans to go back the next day with Prof Clark, diving equipment, and a trained diver.

The next day, the crew went back all suited up and prepared to dive. However, they found the Iver floating on the surface of the lake on the opposite side. We’re still not sure if it was stuck over there or it just floated over. Either way, we got it back and learned a valuable lesson.

It seems as if the Iver got stuck as it was trying to turn. For the next time, we decided to run the same diving mission as a surface mission to check for simple errors such as the turning radius.

However, the surface mission didn’t help. The next weekend we went back out with Prof Clark and a modified mission. We loaded the surface mission, clicked go, and it dove. The Iver had too much weight on it and as it went forward, it dived. Sigh. This time Prof Clark went and got his wet suit and went in himself. We still weren’t able to see it so gave up for the day. The next day it was found the same way. It had floated to the surface except this time it was floating where we expected it to be.

Our new plan is drive the Iver manually to make sure it doesn’t automatically dive, run a surface version of the dive mission, and only then run the dive mission. We could also attach the buoy tether during the dive mission for extra security. Let’s hope it all goes smoothly in Costa Rica. Luckily the volcanic lakes in Costa Rica should have less muddy bottoms and edges than the Bernard Field Station.

Signing off!



Things are progressing very rapidly now as we prepare to depart for Costa Rica in less than 2 weeks time. This is also a very busy time for all of us as all of our classes are presenting us with midterms or finals or mid semester project reports. At the same time, I am pleased with the progress that we have made over the last week or so. The development of the CO2 sensor looks promising at this stage and we are hopeful about completing the building stage this coming weekend. We have also set ourselves a new goal: that of integrating a ph sensor to make alternative models of CO2 emissions from the lakes. 

Meanwhile, we got an interesting e-mail from Don McFarlane this week. For those of you who are not familiar with Don, he is the science lead on this project. He works at Keck Science and brings a rich knowledge of Costa Rica and its volcanoes to the team. 

In his e-mail, he sent us the following picture (taken from BBC):


This is a picture of Poas lake erupting last week. According to the BBC article that Don referenced, the lake is currently erupting and erupting violently. So much so, that this eruption was the worst in Costa Rica this year. 

Here is an excerpt from the article: 

“Earlier this week, Poás in Costa Rica had a small eruption likely related to water flashing to steam in the heating crater lake area. This eruption ended up being the largest so far in 2014, but these types of explosion are fairly common at the Costa Rican volcano. That being said, María Martínez Cruz (OVSICORI) said that the size of this eruption, with a plume that reached 300-meters, is not too common at Poás. This could suggest that more heat is being fed into the upper reaches of the volcano. The webcam at Poás captured the eruption as it occurred, spreading ash mainly within the crater area. If check out the webcam at night, you can see some intense incandesce that betrays the magma just beneath the surface at the volcano.”


Mission One

Hello all!

For these last two weekends, we went over to the Bernard Field Station which is owned by the Claremont Colleges to test the Iver2 in the lake. Jerry and Yukun joined us from the LAIR which is lucky because we weren’t entirely sure what we were doing. 🙂 They showed us the ropes and got us used to the robot. We drove it around in manual mode and tested out its turning radius. We noticed it made much tighter right turns than left.

Akhil running the Iver in manual mode.

We also successfully ran a simple mission. The map was downloaded from Google Earth with some adjustments and by using Vector Maps, the mission was a piece of cake. We plopped a few points down, kept an eye on the turns, and gave it a parking point. Our first mission was a complete success!

Nick grabbing the Iver from the lake.

We went home bolstered  by our accomplishments and began making plans for mission two: diving.


I spy an Iver!