Fredrik Gustavsson - Co-founder of Sensoid Technologies AB
Friday April 27th, 18:00-18:30
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Interview by: Fanny Hahne, Jakob Renmark and Karl Hällström
Location of interview: Zoom-meeting
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Background
Fredrik Gustavsson is an inventor and entrepreneur and is now the co-owner of Sensoid Technologies AB which is a company responsible for Deepod which is a project created to make a small device that can collect different types of data in the water. The purpose of the Deepod project is to increase the knowledge and understanding of the oceans and also let science benefit from this. Therefore Gustavsson has experience in building waterproof sensors and has much knowledge when it comes to the technical parts of a project like this.
Material
For our project, Gustavsson had some good tips in terms of building the sensor and gave us inputs on what the most important things for us to consider could be. First of all, the pressure. After some discussion we concluded that the sensor will probably have to tolerate the pressure at a maximum of around 50 meters. In this discussion we talked about using metal for our cylindric sensor-case, but Gustavsson explained that a plastic-pipe, for example an ordinary drain pipe, would be enough and that it would suit our project better since it’s cheaper and easier to handle.
Technical details of the case
Gustavsson explained that, depending on how we want to be able to use our case in action, different problems will occur. For example, the two ends of the pipe can either be totally sealed or they can be attached so that it’s possible to open the tube without destroying it. It will be more challenging to build the case if both ends should be able to open up, because of the factor that it needs to be waterproof. Gustavsson further suggests a solution where one end is sealed with glue, while the other end is a kind of plug that is pushed in together with an O-ring and some grease, which is then possible to take out. The challenge here is to get the O-ring and the plug to fit perfectly with each other and with the tube so that it’s totally waterproof when sealed. Gustavsson explained that he has worked with similar containers before and said that the best way to do this is to use a lathe to cut a gap in the plug for the O-ring. He also said that if it’s possible, using two O-rings is preferred since it’s more safe if one should break or doesn’t quite work. When it comes to the sensor, the easiest way to attach it to the whole case is to drill a hole in one of the ends, preferably the one that’s stuck. Then let the measuring part of the sensor go through the hole and be outside of the case, and then seal it around the opening. This is the easiest way to get it waterproof but the catch here is that the sensor cannot then be separated.
Testing the cylinder
The best way to test the cylinder and its waterproofness, according to Gustavsson, is to firstly create a higher pressure on the inside than on the outside. Then put the container underwater, and due to the pressure difference the air on the inside will want to get out and thus, any leaks can easily be detected.