How do I build a prototype and team with a small budget?

Just get started. I have been using this site with great success. https://www.freelancer.com/affiliates/bgriffey

I am working multiple ventures at the moment and the resources available on this site are tremendous. Very affordable high quality work. You can have an instant team of professionals.

I concur with the other poster. A 3D printed mockup is a great place to start.

I would not worry about your idea being stolen at this stage. Investors are going to be more concerned that the idea was someone else. For that sake seek patent pending when feasible.

The most critical thing is to get outing the market to validate the product. That is what business is really about.

I advise and mentor Startups in San Francisco Bay Area, and some of them, like you, are in the hardware sector, including Robotics and Computer peripherals.

With prototypes, I would say there are two kinds - representative (a miniature model) and functional (actually performs the task).

If all you want is the representative kind, there are 3D printer services - I googled for Mexico City and found some fairly easily. You would have to see if they are in your budget.
http://www.makexyz.com/printer/rockit-print

It is difficult to talk about functional prototypes without more knowledge of the product. Let me know if you'd like to get on a call.

This 3D printing option would give you a starter kit to take to investors - there are some great investors in the Bay Area that could incubate and grow Non-US startups. Would traveling to the US be an option?

More than happy to discuss further, this is a very admirable field you have chosen. Good luck!

First, you're going to want to patent the system of creating the energy, as long as you're sure it doesn't exist already. While the patent is pending, you should create a business plan that goes into detail about how you're going to create the energy (you can use the patent application as part of your business plan), and how you're going to monetize, or sell it.

You can also go in depth about how much money you're seeking and what you're going to need it for; this is important for investors. Investors will also look at the potential size of your business and the capability of your team; how diverse their backgrounds are and how much they bring to the table.

I'd love to hop on a call with you to further discuss the formation of your team and any other questions you may have. Good luck! :)