Hi there! In this BLOG, I will explain how the electronic hardware development (PCB’s) is done by the electronics engineers of the Solar Boat Team. Our team is building a boat on solar energy, which operates as efficient as possible. For this purpose, we use hydrofoils, which can lift the boat out of the water. However, as our boat is electrical, we need a lot of electronic systems to make our boat work as efficient as possible.
To do this, we spend lots of time behind the computer, which is very close to the coffee machine, so we have a constant flow of people coming by, seeing something with a lot of colours that looks very professional on the screen and saying “lekker bezig!”. But what are we doing?
First, PCB stands for Printed Circuit Board, and it is basically a board (usually green) that has traces (lines of copper) and pads that connect various points together. In the picture, you can see, for example, the PCB of the logger. We think it is very important to know how each component works and that’s why almost all the boat’s electronics are designed and built by ourselves. We have designed, among other things, our own Battery Management System, Energy Management System, 24V distribution, height control, MPPT switch, dashboard and steering wheel and a logger.
When starting with your design, you first need to consider exactly what functions the design needs to fulfil. For example, the logger serves the function of taking data from the CAN bus and storing it on a MicroSD for testing. But the board also needs power to be supplied. This power, in the case of the logger, will come from a 24V bus line. However, your components will work with 5V or 3.3V, so you need to install a set of buck-converters. You will also need a subsystem in charge of the control, in which the microcontroller will be placed, and a subsystem for debugging and programming this microcontroller.
The next step is to translate these design functions into a circuit schematic. Almost anyone can come up with specific functions for a design, but only electronic engineers have the expertise and knowledge to design the boat’s complex circuits. Many design aspects can only be learned by practicing, so the help of Luc Does from the old team has been necessary. The schematic design is the most challenging part in the PCB design process and takes the longest.
Once all of the schematics have been drawn, the actual board needs to be designed. In this phase, components such as resistors and chips have to be placed on the board and connected to each other. This is the most fun part of the design because it is like solving a challenging puzzle and you get a good glimpse of how the final PCB will look like.
Once the board design is finished and everything is properly routed, we need to order the PCBs from Eurocircuits, one of our sponsors. The nice thing about Eurocircuits (besides them sponsoring us) is that they have an online tool that immediately tells us if something is wrong with our production files and if it fits in the technology class we had in mind. When Eurocircuits tells us that the design is OK, we order it and in two weeks’ time we can start assembling the design for real.
When doing small batches, we solder everything by hand. However, for large batches or very complex PCBs we use specialized equipment. In the D:Dreamhal there is a room full of Eurocircuits’ equipment such as a pick and place machine, reflow oven and functional testers. Last week we ordered a lot of different PCBs so we expect to be pretty busy the coming weeks, assembling and testing our designs.
Suzanne Assen / Chief Electronics
TU Delft Solar Boat Team
2628 CN Delft