With an initial prototype complete, it was time to test it out! In terms of functionality, the rudder and motor speed can be manually controlled, data is sent back to a live dashboard and data is periodically sent to a database for reporting purposes. We wanted to test how it performs in the water and how much power it consumed in reality vs our experiments. I also created a function to keep the boat moving at a constant speed, so we tested that as well.
So one chilly evening I went down to the pond again with my friends Phil and Catrin. We unpacked the boat, turned it on, put it on the water and we realised our first problem. The boat was so light that the propeller wasn’t in the water. So with some bottles of water at hand we strapped them to the back of the boat to make some weight adjustments. The good news is that the boat didn’t leak and the prop didn’t fall off, but it was very difficult to control. One of the features I designed was that when a speed or position is set for the motor or rudder, it makes the change gradually, so that excessive forces do not suddenly happen. Whilst this was fine for the acceleration of the motor, it meant that the rudder took a second or so to move. But by the time the rudder had moved all the way over, the boat had already passed the direction I wanted to steer in. So a yo-yo-ing affect developed as I steered the boat left and right and left and… That’s one feature I’m going to modify! The boat was a bit sluggish in it’s turning as well, so I’d probably have a bigger rudder. Although issues like this don’t really mater as what I’m testing here is the software rather than the design of the prototype boat, as the real boat will be completely different.
The other feature that got in the way was my safety feature. The boat motors kept cutting out, which would have been because of a dodgy wifi connection. So every minute or so I had to recreate the connection to the boat. But at least the boat didn’t storm off, oh no wait, it almost did. I activated the speed hold function and the boat rocketed off, so I hammered the kill button because by this time the back of the boat was now very close to the water! Luckily the boat remained dry and we were able to take everything home in one piece.