Mini AMOS

Here are some pictures of the latest AMOS version (perhaps to be called "Mini AMOS"). It uses the same electronics boxes as the regular AMOS, except it only uses a 4 foot long bodyboard, doesn't have a solar panel, and uses a water propeller instead of the air propeller on the standard robot. The board shown below doesn't have a survey-grade GPS antenna (just uses a GPS / USB stick), but that could be added later if desired. As it stands right now, its weight is only 4.5 kg. 

There will need to be some minor software modifications to drive and control the water propeller, but these should be relatively minor. It will be interesting to see how fast it can go, and / or what kind of performance it has in wind, waves, currents, etc. 

Flexible Underwater Ribbon Cable Guide

 The previous rigid 3-D printed shell that was used to join the underwater WeatherBox to the main electronics box on the AMOS surfboard needed to be replaced with something flexible that could flex and swing out of the way whenever underwater obstacles were encountered. 

Some inexpensive plastic tubing was purchased at Home Depot, and 3-D printed adapter parts were constructed for either end of the tubing, to join it to the WeatherBox at the bottom end and the main electronics enclosure at the top end. 

This made a nice, water-tight conduit for the camera cable to follow, but it proved to be difficult to design the top piece to be strong enough to withstand large bending moments that were produced whenever AMOS passed over a shallow, rocky area. Three different top-piece designs were fractured in separate field tests before switching to a slightly different design using a large cable gland at the top. Instead of fitting the top end of the tube over a 3-D printed male plastic piece, the top end of the tube was fitted inside the cable gland. A small amount of heat treatment with a heat gun was applied at the top end of the tube to allow it to compress slightly and ensure a snug fit. 

This design worked perfectly: it had enough "flex" to be able to swing up out of the way of obstacles, without putting too much stress at the top cable gland connection. Here is a video of AMOS crashing into an underwater rock. The WeatherBox and its cable guide swung out of the way and were undamaged:

I enjoy combing through the videos from these tests, looking for fish. Here were a couple that were briefly captured in the most recent test yesterday (October 6):

My favorite clip came at the end of the test when AMOS was just floating near a partially submerged tree. I really like how the light from the sun is shining on the tree in this video, it looks kind of magical:

AMOS Captures Some Fish

 Things have been busy lately, and there hasn't really been much occasion for taking AMOS out in the field. Over the last week though, I was able to develop some software for saving 30 fps 1920 x 1080 video files on AMOS, while still continuing to do all of its regular navigation and data saving stuff. Testing and debugging was done in the pool, and everything seemed to be working well. 

This morning I took AMOS out to Kelly's Creek to test how the navigation, sensor data saving, and video recording all worked together. I was worried that the addition of the video recording in a real environment would slow down the other functions, possibly resulting in sluggish handling or missed data samples. Everything seemed to work pretty well though, although when I had plotted the course the night before, I had not realized how low the water level actually was. The waterline was about 10 m in from where it appeared to be on the ArcGIS map that was used to setup the course. Unfortunately, the WeatherBox  that housed the camera underneath AMOS struck a rock at full speed, and the 3-D printed extension piece that connected it to the main electronics enclosure snapped under the strain. The WeatherBox was quickly flooded, but I was following close behind in the kayak and was able to turn off AMOS's power switch a few seconds later. Clearly a more flexible extension piece will be required here. Perhaps something like a short rubber hose could work?

Despite this accident, the rest of the test was a success. Depth, temperature, and conductivity data were all recorded normally, AMOS navigated itself normally, and 9 video files were recorded, mostly of air bubbles and river vegetation, but at 1:10 of the video below, you can see 3 small fish swimming by for a few seconds:

The end of the above video is where the WeatherBox struck the rock and the camera module was flooded. Unlike the last camera flooding which occurred in salt water, this one was in fresh water, and after storing the camera module in a bag of desiccant for 12 hours, it was confirmed to be unharmed. 

AMOS Looks Underwater

 Last month's assumption that the o-ring seal on the WeatherBox required improvement proved to be correct. The printed part had tiny imperfections underneath the o-ring that allowed water to slowly leak through. A WeatherBox customer who was using it to observe a muskrat underwater came up with a brilliant solution: he found that using some marine goop (ex. https://www.homedepot.ca/product/amazing-goop-marine-109-4-ml-3-7-oz-/1000183125) in the channel holding the o-ring worked to fill in the small imperfections in the plastic and create a watertight seal. I've built a few WeatherBox enclosures since then with the channel filled with Marine Goop and they have all worked quite well.

To take pictures and video underwater with the 6 foot AMOS surfboard, an extension piece was required to get the WeatherBox below the waterline. The bow of the surfboard where the camera is located is pitched upward at about a 20 degree angle, so this requires a curved extension piece. The creation of this extension piece required a couple of weeks. At first, rendering the model in OpenSCAD took days for my laptop to finish, although later iterations of the model used some 2-D optimizations with extrusions that shortened the rendering time to about 24 hours. The first two model attempts also had small gaps on the side with the largest radius of curvature, which led to leaking. Eventually a working model of the curved extension piece was created:

The extension piece was fitted on AMOS and used to capture this underwater backyard pool video:

Apologies to viewers for the acting talent used in the above video. In Nature Robotics operates on a tight budget. 😉

Coming up next week is the final round of  the 2021 edition of the Ocean Startup Challenge (https://oceanstartupproject.ca/challenge/). In Nature Robotics is in the mix again this year, and will be pitching on Thursday, September 9. 

Drip, Drip, Drip, How to Make a Watertight Window?

 Some work has been done over the last couple of weeks on trying to adapt the WeatherBox to function as an underwater camera enclosure. This work has been educational but not entirely profitable. Some underwater tests had been done in the pool, and at the time appeared to be successful, but they were too short (less than 5 minutes) to really prove out the leak-worthiness of the enclosure.

A longer test in a real-world environment confirmed that the enclosure leaks too quickly to be of any use for underwater pictures or video. A slightly modified version of the enclosure with a longer stem was attached to the underside of AMOS and used to record a video frame every second, for a 1 hour test along the shoreline in Cap Brule, New Brunswick. The stem was not really long enough to keep the camera underwater all of the time, and the mounting pins inside this particular enclosure had snapped off, so the camera board was not properly centered. The camera software uses an auto-brightness adjustment, which I think was confused by the alternating views above and below the water. 

The camera ceased to function after about 20 minutes of operation. When the boat was taken out of the water about an hour later, it was half-full of sea water. The camera board was immediately rinsed and dried off, to no avail. A subsequent test confirmed that it no longer functioned at all. 

Some decent depth, temperature, and conductivity data was collected for the test, showing a nice correlation between the 3 parameters: the shallower water was warmer and had a higher measured conductivity.

 Conductivity

Depth

                                                                        Temperature

Here is a video created from stringing the individual 1 Hz video frames together and increasing the playback speed by 5x. Not much to see really, just a lot of bouncing up and down and the occasional piece of seaweed:

I'm going to test out some changes to the camera enclosure cap this week; at this point it looks like the weak point is the O-ring seal with the enclosure window. 

AMOS Goes Camping

This past weekend I went with my daughter to her triathlon training camp at Kejimkujik National Park in Nova Scotia. We purchased a campsite for two nights and brought the tent, her bike and other triathlon-related equipment, a kayak, and of course AMOS! While Kirsten practiced swimming, biking, and running, I figured I could test out AMOS and follow around in the kayak.

The weather on Friday turned out to be awful though. Tropical storm "Elsa" passed through the area late in the day with high gusting winds and buckets of rain. The fly on our camping tent kept nothing dry, as rain was easily blown underneath, so that by Friday evening, it was basically raining INSIDE the tent too. We  decided to put AMOS, the bike, and most of the other equipment in the tent, and ended up spending the night in the van instead. 

Fortunately the weather on Saturday was much better, and by noon it turned into a sunny hot day. While Kirsten was training around Merrimakedge Beach, I mostly kayaked and observed AMOS as it followed a pre-programmed sampling course. Unfortunately I had forgotten to bring a necessary cable for the depth sensor, but did manage to get some good conductivity and temperature data over a few hours:

 Over the last couple of weeks some progress has been made on the Android app for viewing AMOS and phone / tablet positions on an Esri / ArcGIS map: 

At present you can see the position of AMOS (yellow boat outline), and the position of the phone / tablet holder (white stick figure), but there is no data visible on the map yet, just some diagnostic information below the map.

New Brunswick Road Trips

 At the time of this writing, our home province of New Brunswick is closing in on its previously stated target of having given 75% of its populace at least one dose of a Covid-19 vaccine. The achievement of this target is supposed to lead to a loosening of restrictions, although I am not sure exactly what that means. Hopefully it will mean that we will be free to travel outside of the province sometime soon. In the meantime, AMOS has been busy traveling inside the province, doing demonstrations and collecting data. 

On June 03, AMOS was in Salisbury, doing a demonstration at some local wetlands. This was for a community project organized by high school students Daytona McMackin and and Rhianna Johnston. Amongst those in attendance were a grade 5 class from a  local elementary school, researchers from Mount Allison University, and members of the Petitcodiac Watershed Alliance. 

photo credit: Jennifer Colpitts, J Colpitts Photography

photo credit: Jennifer Colpitts, J Colpitts Photography

 photo credit: Jennifer Colpitts, J Colpitts Photography

photo credit: Jennifer Colpitts, J Colpitts Photography

photo credit: Jennifer Colpitts, J Colpitts Photography

The wetland area was fairly challenging in terms of its topography, with numerous grassy hillocks that required some careful route planning and / or manual driving to properly avoid. On a few occasions, these were not avoided, and AMOS became stuck, requiring a couple of outings in the kayak to nudge it into an area of deeper water. Apparently the demonstration was still suitably impressive for at least some of those in attendance: one grade 5 boy stated that he would ask his parents for an AMOS this year for Christmas. 😊

Here is the temperature and conductivity data collected with the AML Oceanographic probe:

The following week I took a trip back to the Lake Utopia area of New Brunswick, to sample Trout Lake, a small lake connected to the east end of Lake Utopia. The day was very hot and humid, and there seemed to be lots of fish (trout?) jumping out of the water to grab tasty flies. AMOS collected temperature, conductivity, and depth data over parts of the stream leading to the lake and the lake itself:

The above temperature data showed an interesting "cold zone" in the southeast corner of the lake where a stream emptied into it.

Much of the lake was quite shallow, although the middle area was a few m deep. 

This past week also included some software updates for both AMOS and the BoatCaptain PC software. It is now possible for customers to easily apply software updates to the AMOS boat by sending them through BoatCaptain. This should make it easy to add new features and improvements going forward. 

AMOS Goes Overseas

 The last couple of weeks have been quite busy getting the first commercial order for an AMOS Board Kit ready for shipment. The order came from South Korea, so the first order of business was trying to find a safe and legal way to ship the 12 V, 10 AH LiFePO4 (lithium iron phosphate) battery by air. This unfortunately consumed a number of days trying to contact local dangerous goods shippers, checking out dangerous goods shipping courses, and then trying to see if there might be some way to find the same (or a similar) battery locally. Eventually a local reseller of the same battery was found, but purchasing the battery required a Korean phone number (for security reasons?) which I did not possess. So the final solution was to simply give the customer a discount and recommend they buy the battery themselves from the local reseller. 

A stock unit was mostly ready for the sale, but a fish finder (for measuring depth) and solar panel needed to be added, and some extra wiring was required. These parts arrived after about a week and the wiring was completed, the magnetometer calibrated, and the unit made ready for testing just in time for the long weekend. We had made plans to go to my parents' cottage in Cap Brule for the long weekend, but could not get there until Saturday night. Sunday was rainy and very windy, with gusts up to 70 km/hr, so no testing could be performed that day. The following day was less windy (20 km/hr) but the cold waves outside the cottage were still a few feet high and smashing against the rocks. Not an ideal location to launch a small kids' foam surfboard. Fortunately the river in town in Shediac was more sheltered, so I took the boat over there. It went through a planned grid course very nicely, although the wind and current did blow it off course a little bit in the middle parts of the river: 

Unfortunately I had neglected to configure the software to record depth and temperature readings, so although the navigational capabilities of the kit were confirmed, the sensing functionalities were not. That's why things are tested before shipping right? We needed to leave soon to get home for a track and field practice, so the software was configured properly this time, and the boat taken over to a nearby lagoon for a quick test. The lagoon was quite shallow however, so although temperature and depth data were both collected, the depth readings were all 0.6 m, the minimum depth resolution of the transducer. The transducer was tested one final time back home in our pool to confirm that it gave readings between 0.6 m and 1.1 m as it was lowered and raised in the water. 

Last evening, some final software was setup to change the wireless module on the Pi to act as an access point. This was first tested out on a spare Pi to make sure that it did not render the unit "unconnectable". Fortunately it worked, and will be nice out in the field for sending and receiving large files. 

This morning was the final boxing up, which required a couple of hours for finding a suitable box, packing materials, and printing shipping labels. Here is the completed shipment, which Kelly kindly volunteered to wait in line (twice!) at the post office to deliver. 

Lake Utopia Canoe Trip

New Brunswick is home to a number of beautiful lakes and rivers that would be ideal for AMOS water monitoring. One such lake that I learned about recently is Lake Utopia, located in eastern Charlotte County, about 1 km northeast of the town of St. George. According to Wikipedia, it has a couple of claims to fame: it is connected to the Magaguadavic River by the second deepest natural canal in the world, and according to local legend, the lake is inhabited by a sea monster known as the "Lake Utopia Lake Monster". 

My daughter Hannah and I had made plans to drive out to the lake with our canoe and AMOS this past weekend. It was quite windy (28 km/h from the northwest according to the Weather Network) and still fairly cold (high of about 12 deg C) so a route was made for AMOS that stuck close to the western shore of the lake, starting from Canal Beach, and following a circuitous route down the canal to the Magaguadavic River. I had previously connected the fish finder / depth transducer to the boat, along with the temperature / conductivity probe, and AMOS was set to collect this data throughout the trip at one second intervals. 

Even in the canal, the wind was quite strong, working against us and making for a slow trip. We were a bit faster than AMOS in the canoe, so would usually canoe a few hundred meters ahead of it, then take a break and wait for it to catch up. Here we are in front of an old covered bridge on one of our breaks:

AMOS came along shortly afterward:

I was encouraged to see that the boat performed well despite the relatively high wind. Hannah shot this video as AMOS was rounding the point to go from the lake into the canal:

We made it to the Magaguadavic River, and paddled a few hundred meters down there, towards the town of St. George and a hydroelectric dam. We soon turned around though, as it was getting late in the afternoon. Here is the data that AMOS collected over the trip:

Depth (m):

Most parts of the canal were about 4 m deep, although AMOS did pass over some much shallower parts (indicated in purple) and there was a much deeper area (indicated in red) near a bridge that was over 15 m deep. 

Temperature (deg C):

I found this temperature distribution to be interesting / perplexing, since it shows that the warmth from the shallows at the mouth of the canal was being "transported" down the canal, although the water at the surface was quite clearly moving from the canal into the lake, since the wind was ~ 28 km/h from the northwest. Perhaps this means that the deeper, non-surface water was flowing in the opposite direction, from the lake into the canal, and that diffusion and / or turbulence from the wind was allowing the warmer water to come to the surface? 

Conductivity (ms / cm):

Overall the conductivity was quite low throughout, with only some slight differences. Conductivity near the shore of Canal Beach seemed a bit higher, perhaps due to the sandy soil and shallow water level. 

I hope to make some return trips to Lake Utopia later this spring and summer, to sample some of its other sections. It's a great spot to spend a relaxing day outdoors! 😎

Swimming With Beavers and a Birthday Road Trip

 While AMOS Orange was being repaired last weekend, I took the foam surfboard over to a local beaver pond to test out the camera software and the new AML conductivity / temperature sensor. The hope was to have AMOS get close to the beaver lodge and snap a few pictures, while at the same time make sure that the temperature / conductivity sensor gave reasonable looking data. 

I turned on the boat, then rummaged around in my backpack to pull out the laptop and wireless transceiver. As I was doing this, I was surprised to hear the propeller whir into action; it had achieved a GPS lock sooner than expected. I set the electronics aside and then ran down to the water's edge to make sure the propeller didn't collide with a nearby concrete culvert. It didn't, but I tripped on some uneven ground, and tumbled into the water. It was only a couple of feet deep at the edge, but was deep enough to get a pretty cold soaking. 

AMOS was off, so I let it follow its programmed route while I tried to dry off a bit in the sun. Once it got close to the lodge, it unfortunately became stuck on a patch of surface ice:

so the pictures that it took of the lodge were not as "close-up" as I had hoped for:

The temperature and conductivity data seemed pretty good though:

Temperature:

Conductivity:

On my birthday (April 07) I had a chance to visit Lime Kiln Cove with AMOS Orange. Steven had recently repaired the leaks in the boat, and added some layers of epoxy to give it more strength and resilience. 

I 3-D printed a bracket to fix the conductivity / temperature probe to the front of the boat, and set the software to collect data at one second intervals as the boat was following its course. The actual vs. planned course of the boat can be seen here:

The planned route is indicated with yellow lines and dots, and the actual route is given by white lines and dots. The satellite data used in this and the other images below is a few years old: the fish farms located in the southern part of the image no longer exist. A local resident who was observing this test told me that they were removed a couple of years ago.

The wind was out of the northwest that day, and tended to push the boat a bit off course near the areas where it was making 90 degree turns. The tide was a bit lower at the end of the test, and the boat became stuck around some rocks near shore as it was returning. I was able to use the remote control at that point to get it turned around and off the rocks so that it could drive itself back to the starting point. 

Some videos of the testing can be found here: 

https://drive.google.com/drive/u/0/folders/1OhqVCtVhsO2azNTflnW3Eh8G-0ZSdGth

In a couple of these you can see that the boat has some issues with stability in the presence of a cross-wind. This was an issue for the conductivity measurements at some points during the test (the spikes in the graph of conductivity vs time below):

The probe likely lifted out of the water at times, resulting in falsely low conductivity readings.

Overall though, the conductivity and temperature data looked pretty reasonable:

The repairs held up for this test, and no leaking was observed. But for most applications, I think a surfboard design would be preferable. AMOS Orange is relatively heavy and is about 3 times slower than the foam surfboard, given the same air propeller (it would probably need a stronger air propeller, or perhaps even a water propeller added). When used without a significant payload, as it was for this test, it sits fairly high above the water, making it unstable in choppy water or windy conditions. Still in some situations, it might prove useful, for example if a very large payload was required. 

The Holey Maiden Voyage

 March winds, April showers, help to bring the May flowers, but those March winds aren't great for doing AMOS tests on the open water. Nevertheless, the forecast for St. John was decent last Sunday: overcast with winds from the northwest at 17 km/h, so I packed AMOS Orange into the van, loaded on the kayak, and drove down to McLarens Beach, just a few km west of St. John. Oddly enough, there were two other kayakers already paddling out on the water, around the Irving Nature Park. They were interested in AMOS, but as I was following the robot from the kayak in a different direction, they warned me to "be careful  out there on your own, you'll die quickly if you fall in". 

Below are a couple of videos of launching the boat, and having it go in a circle close to shore, shortly after the launch. It actually kept going in circles, which I believe was the result of a bug from having the first waypoint designated for taking 10 pictures at different angles. Only one picture got taken, but the boat kept going around in circles, close to shore, so likely there is an infinite loop that will need fixing later in the software. In a way it was good for getting the videos though, because I was too nervous later on in the kayak to fumble around with my phone, and only used it while still on shore.

To get around this problem with the first photo waypoint, I pulled out the laptop and created a new set of waypoints that did not include any photos. AMOS followed these quite faithfully:

only occasionally deviating a few m from the intended course. I followed along in the kayak, but stayed close to shore, within about 50 m. With the offshore, northwest breeze there were only some slight, gentle waves, and nothing very risky, but I didn't want to risk leaving the safety of shore until AMOS's battery went low and it went into low power mode, on the return trip. I paddled out to the boat, and noticed that it was listed a bit to one side, which could only mean one thing: water intrusion. I attached the tow rope, and towed it back to the McLaren's Beach starting point. There, I tried to pick the boat up, but could only barely do it, as quite a lot of water had gotten in. By tilting the boat on its side, I was able to drain most of the water out through a small gap between the solar panel and the gasket, enough so that I could lift the boat into the back of the van and drive it back to Hanwell. 

A closer inspection at home revealed the source(s) of the water intrusion. One large hole and a second damage area on the bottom of the boat:

There were some pebbles and rocks on the beach where AMOS was launched from, and I did push and pull it in and out of the water from that beach a few times that day. 

At some point those rocks must have damaged the bottom. Steven is currently working on repairing and strengthening the bottom in order to withstand this sort of (typical) abuse. He is also working on ideas for reducing the weight of the boat, as its current speed is relatively slow: only 2.4 km/h for the sampling course in this test, vs. about 5.5 km/h for the surfboard model. Some of that slowness could likely be attributed to the extra water weight the boat was carrying though. 

In other news, the Raspberry Pi driver software for the AML Oceanographic temperature / conductivity sensor has been completed, and a test program has been written to try it out: it seems to work great! The temperature seems quite accurate and precise, and it had no trouble detecting a teaspoon of salt dumped into a few liters of water. 

The Boat Captain software has also been updated to allow the user to easily create lawnmower-style sampling grids by clicking and dragging a surface area: 

Ready For a Water Test

 The last couple of days have been warmer than usual, so hopefully it will soon be time to try out AMOS Orange in some actual water. A more solid, stainless steel mounting post for the GPS antenna was substituted for the 3-D printed version that had been used previously, and some wiring was completed to add humidity / temperature sensors and a solar power level circuit.

For now, the interior of the boat is just filled with scrap pieces of pink insulation foam:

as a precaution in case the hull gets punctured.

The conductivity / temperature probe arrived this week from AML Oceanographic, and a software driver for capturing the data has been written already. I've also started writing a test application to try it out. It just uses a simple RS-232 serial connection, so I'll hookup a USB-RS232 to the AMOS computer for it. 

AMOS Orange

It was an exciting day yesterday, as Steven delivered the newly built AMOS hull:

The orange color is really vibrant, which should make the boat easily visible from a distance on the water. It weighs about 30 lbs, so heavier than a surfboard platform, but the interior has plenty of room for batteries and other equipment, which should provide it with plenty of endurance and measurement flexibility. 

In other news, we now have a distributor in New Zealand, Australia, and the Pacific Islands. The Stream Ltd. (https://www.thestream.nz/) has signed on as our new distributor on the other side of the planet. They are an environmental services company, specializing in river, coastal, and watershed monitoring.

And lastly, the AMOS Board Kit can now be found on RobotShop's Canadian and US websites (https://www.robotshop.com/ca/en/amos-board-kit.html). (Product photos provided by Moments By Kassie: https://www.facebook.com/momentsbykassie). 

We're always trying to spread the word about AMOS; if you have any good ideas, or would like to help out, please contact us!