Smart Buoy [Waterproofing, Dashboards and Deploy]
Introduction: Smart Buoy [Waterproofing, Dashboards and Deploy]
This Smart Buoy series charts our (ambitious) attempt to build a scientific buoy that can take meaningful measurements about the sea using off-the-shelf products. This is our final tutorial— make sure you’re up to date, and if you need a swift introduction to the project, check out our summary.
Part 1: Making wave and temperature measurements
Part 2: GPS, Radio (NRF24) and SD Card Module
Part 3: Scheduling Power to the Buoy
In this article, we show you how we designed the casing to protect our Smart Buoy from water, waves and shark attacks. We also explain how we connected it to the base station, which hosted a database and interactive dashboard to explore data in real time.
Supplies
As this is the final stage for the project, you’re going to need ALL the supplies:
* Arduino Nano —Amazon
* Raspberry Pi Zero —Amazon
* Battery (18650) —Amazon
* Solar panels —Amazon
* Blocking Diodes —Amazon
* Charge controller —Amazon
* Buck booster —Amazon
* GPS module —Amazon
* GY-86 (accelerometer, gyroscope, barometer, compass) —Amazon
* Water Temperature sensor —Amazon
* Power monitor module —Amazon
* Real time clock module —Amazon
* Radio modules —Amazon
* i²c multiplexer module —Amazon
* 3D printer —Amazon
* PETG filament —Amazon
* Epoxy —Amazon
* Primer spray paint —Amazon
* Rope —Amazon
* Floats —Amazon
* Glue —Amazon
Get The Smart Buoy Code On Github
Step 1: Tutorial 🤖
Step 2: Casing — Buoy
When we designed the Buoy, we had a couple of key things in mind: it needed to fit all the electronics inside, have slots for the solar panels, radio aerial and water temperature sensor. It also needed(!!) to be watertight and float. It also required an anchor point, so it wouldn’t just float away.
We used Autodesk Fusion 360 software to design the Buoy and we’re pretty happy with how it turned out. However, we shot ourselves in the foot slightly by not including a sealable slot for programming the Arduino, and were at the mercy of getting everything working perfectly before we glued it together.
Step 3: Casing — Base Station
The Buoy communicated via radio and the messages were received by a base station. In the previous tutorials, we used the radio module with an Arduino for simplicity. The base station used a Raspberry Pi, which connected in the same way but allowed for much more processing.
There are many great open source cases on Thingiverse, including this one that prints in one piece and has cut outs for wiring.
Step 4: Print — Buoy
3D printing is great fun but also time consuming and rage-inducing. 33
Luckily, however, some people are much more experienced than we were and were quite helpful. Thanks to reddit user @dbcottonhead, we looked into PETG filament, which is meant to be much more durable and creates stronger shells. These are important things to take into account when making something that is expected to float in a salty sea in 40°C sun, while possibly smashing into some rocks…
To ensure waterproofing, our main focus was on layer adhesion:
* Thin layer heights of 0.3mm helped reduce the size of gaps
* 4 perimeters to reduce possibility of gaps and give wall strength
A completely solid Buoy would be watertight, but it also wouldn't float as the density of PETG is higher than that of water. We chose to have a 15% infill on the print.
Each half took around 24 hours to print and used 500g of PETG. The finished print was quite smooth, but with the stringiness and blobs you would expect when using PETG with FDM printing.
Step 5: Solar Panels
The Smart Buoy featured four solar panels equally spaced around its circumference. Each cell was capable of producing 5V at 60mA. A typical Arduino nano requires ~20mA, so we hoped this would be fine for our system. We soldered wires to the rear of the solar panels and connected to the rest of charging system.
We threaded the wires through and then glued the solar panels into water-tight position.
Step 6: Motherboard — Perfboard
With a lot of determination, solder, and wire, we connected the electronics together on perfboard.
We pushed the radio aerial and water temperature sensors through their respective holes and glued them into position.
The perfboard slotted neatly into the Buoy and we glued it into position. 98