How could we take a HEXBUG and make it swim underwater? That is the challenge we set out to answer with this product design. We knew it would require both programming and complex sensors, as well as attention to the physical design attributes. To create a realistic swim pattern, our first challenge was to get the fish to swim right to left. We loaded the on-board software with 9 different swimming sequences that are randomly executed so that it would always do something new and appear to never repeat itself. Once that was accomplished, we moved on to engineer the tail. Instead of a basic left to right motion, we used electromagnetic coils and magnets to push and pull the multi-position tail to the right, center and left positions very quickly. Now that the Aquabot was swimming, we needed it to climb and dive. In order to achieve this, we had to tweak the software programming so that the fish would swim at different speeds – slow, medium and fast. We also had to fine-tune the tail design so that when it moved fast it would swim down, and when it moved slowly it would swim up. This created a more fluid, organic swimming pattern for our Aquabot. The final feature we wanted to imbed was to make the fish energy efficient. This called for a complex sensor and processor that would automatically turn the fish on when in water, by measuring the electrical conductivity of its environment. We also installed a sleep feature, so that after five minutes in the water, the processor would put the fish to sleep to save battery life. The result? A mesmerizing water activated robotic fish that moves so realistically that it fools most cats and some humans into thinking it’s alive! Here are some of the key steps and supporting images that document the development of the HEXBUG Aquabot. Enjoy!