Clearly your aesthetic is your strongest point, the minimal style with a small creative spark works and in my view you can hold onto it and further refine it.
As far as ideas go, I love the customizable stool, class work. Being able to go into a store and pick your own parts out of different colors/materials is a great addition to a product and the buying experience.
My remarks are mostly about depth and details.
I would like to see you take your projects further and incorporate more information from multiple perspectives into your product design process, to establish a sense of realism about how your products could come into the world. I also miss a bit of a backstory about the context with some of your projects.
I very much appreciate you including other fields of work - interactive prototyping and art. Keep on integrating your different works into future projects.
At the school where I am from, that Arduino stuck to a T-shirt - though it's nice you got the Flexinol to work - would hardly be called a prototype but rather a first demonstrator and not something you would show beyond your first project days, let alone in a portfolio website. I also don't specifically see what the concept is. I like the idea of remotely being able to touch someone, say you want to greet someone or let someone know you're there. But I feel the concept needs to be worked out and supported much further.
Also your project Pinched lacks depth - it's a nice shape but could be refined much further. The digital model looks different than the physical model doesn't it. Also you see how scale is so important. It would be a nice exercise to play with different parameters such as scale, surface tension and curves and rapid prototype them to learn about form and process.
It's more important to communicate your code structure than showing the code itself. You generally don't show code in a portfolio. From your CV it is clear that you have a great set of abilities and your portfolio only reflects that to a small extent. Do you have more work to show that you can handle certain software programs or other skills? With the foresight of applying for jobs that may be an important criterium.
Your art piece is very nice. I would have liked to see more of your process there. A tiny detail is that it would probably have looked better with a gradual exponential increase of height. How about adding some splash and painting the outer sides in a fluorescent orange? A tiny detail about the corner lamp is that it needs a cord winder because it does a lot of disregard to the nice clean feel of the overall concept.
See if you can define yourself a bit more - for example think about what can go under your name as a tagline or title.