For next week, build a functional electronic prototype of your project. It should behave in the way you’d like your final product to, which may require construction of essential mechanical elements as well. That is, you want to make something that allows you check, for example, whether the sensors you’re using can measure what you need them to and that the actuators can affect the world in the way you want. This prototype should allow you to evaluate the technical feasibility and interaction design of the product.
It’s fine to use things like Arduino boards or SparkFun modules. We’ll be doing custom PCB designs after the mid-term. But, remember, you’re trying to evaluate the feasibility of an eventual product, not just build a one-off. Keep in mind things like the total cost of the components you’re using, the power source you’ll need to use, the way you put things together, etc.
Please note that ordering components will take time. You should whatever you need on Friday, and even then they may not arrive until Tuesday or Wednesday, which doesn’t leave much time for prototyping.