A month at MakerBay with ScoutBots — Protei Rohak
During the month of July 2017, I did my internship with Cesar Harada at ScoutBots Protei and contributed in the projects going on at MakerBay such as WWF’s Marine Litter Detective. I had been working on Marine Litter Detective and Protei_Rpi from March to June and I wanted to continue the work throughout the summer. Thus, I was super excited when Cesar called me on board to collaborate on the next version of Protei (now called Protei Rohak v12.0). This post traces my journey at ScoutBots and MakerBay, the things I learnt from the amazing people and the projects around me and serves as a documentation for all the undertaken work.
tl;dr : I made this webpage for the data visualization part of Marine Litter Detective and I gave this talk about the project at an event organized by the Consulate General of Switzerland in Hong Kong at MakerBay. I wrote about the first two weeks with ScoutBots here. In the last two weeks, Cesar and I developed v12.0 of Protei — Protei Rohak. The design and fabrication of the boat was handled by Cesar, while the electronics and code was formulated by me. Some videos and pictures of Protei Rohak can be found here.
Week 3 & 4
In the third and fourth week of the internship, the focus shifted entirely on Protei. Complying with standards, we decided that the goal for the following version of Protei would be to be controlled via an Android app (computation) and an Arduino (motor control).
This is the first version of Protei which has an Android phone on board, extending its computational power and bringing it a step closer towards autonomous navigation.
The design and fabrication of the boat was handled by Cesar, while the electronics and code was formulated by me.
Making Protei Rohak — Electronics & Code
The idea of Protei Rohak was to move in the direction of giving Protei autonomous control. This includes setting a waypoint on Protei and letting it decide where it should go next. Although this goal may seem far right now, the first step was to incorporate an Android phone on board Protei. In this section, I will provide details about the electronics parts list and the Android and Arduino softwares on Protei Rohak. More technical details can be found on our GitHub repository.
- Arduino Bluetooth Module — HC-06
Since we had to include an Android Phone which would act as a control center for the boat, it needed to communicate with the Arduino which manages the motors. We chose serial over Bluetooth as the communication protocol because of its ease of setting up and use. - Motor Controller, Motors and Battery
We decided to use the electronics from Seeed Studio’s Hercules kit since it included high torque motors and their controller, which was perfect for our application. - Arduino
The Arduino controls the motors according to the MQTT commands it receives via Bluetooth from the Android App. Through the app, it subscribes to a MQTT channel via the broker, which is set up on an AWS server using Mosquitto. A python script publishes messages to control the direction of the motors. - Android App
The Android App is the control center of the boat. For testing, we used HTC Butterfly, but any Android Phone can be connected to the Arduino via Bluetooth after installing the Protei App.
- The MAC address of the bluetooth on the Arduino
- Connect Button to pair the phone with the Arduino using Bluetooth
- The RX field shows the last command received by the Phone from the Arduino
- TX shows the latest command sent from the laptop to the Android phone, and to the Arduino.
- The app keeps a counter for the current position of the Rudder and the Sail. A negative sign indicates the left direction.
- The app also indicates the Phone Gyroscope status. We can log this data to estimate the wave direction and speed.
Making Protei Rohak — The Body
The first step of building Protei Rohak was to mark all the dimensions of the boat which need to be cut out. Cesar chose EVA Foam as the main material of the boat as it is a light weight, durable and waterproof material. He chose to build the deck and keel of the sailboat out of pure wood.
After marking the dimensions and cutting out the pieces, we proceeded to stick them together with an adhesive.
We made space for putting the electronics on board — which are placed in airtight containers in the front and back of the ship.
After Cesar prepared the mast and the sail, the boat was ready! The last step was to add the weights on the keel to stabilize the boat and test the electronics and the Android on board the boat.
We also fabricated our own 3D printed parts for the sail and rudder winch, which is attached to the two motors. Thanks Cesar for teaching me how to design stuff on Tinkercad.
Testing
Here are a few videos on the testing process of Protei Rohak:
And here’s a video explaining the features of the Android Phone, App and electronics on Protei Rohak:
Sail Day!
For testing Protei Rohak in waters, we chose the Kai Tak Cruise Terminal because of its proximity to MakerBay and ease of access.
But before we set sail — there was one last thing to do:
After we made sure everything was set up according to this document, we were ready to go!
Acknowledgements
Thanks to all the folks at Makerbay for being their awesome selves. Thanks to WWF-HK for making me a part of Marine Litter Detective and the Consulate General of Switzerland in Hong Kong for having me as one of the presenters at CHIC. And finally, I cannot thank Cesar Harada enough for giving me the opportunity to collaborate with him and contribute to the MakerBay, ScoutBots and Protei family.
