Further thoughts (for the OP and anyone starting a business):
1. You probably don't need an investment, you need sales. How are you going to get sales if you don't have an investment? That is a good and difficult question, but the reality is that most investors don't like investing in businesses that don't have sales. So if you don't have sales, then you need to find users, happy users, very happy users, users who will say your product is so much better than any others they have used. And then they will have to explain why if your product is so good they only use it for free as opposed to paying for it. Bottom line - unless you create enough value that someone wants to use and purchase your product you won't have much of a business for very long.
2. So, let's say you can get some users to try and like your products. At some point after proving that you have happy users you need to get paying customers. How many customers do you need? That will depend on things like your projected selling price for each product. That price times some volume will equal your revenue for that product. And likewise for each other product. When you add up all the revenue from all the products for a year that will be some number. You need to get a grip on what that number is. If that number is X your own personal income (salary) will be something less than X. In addition to your salary and other expenses (Sales, General, and Administrative), you will of course have the Cost of Goods Sold (for parts and labor). All of that will need to be subtracted from the total revenue. If there is any money left over that is your profit, of course.
Revenue - SG&A - COGS = Profit
How much profit can there be in the first year, second year, third year? Whatever profit there is, over time or at some time, some % of it will eventually have to go the investor to pay for their investment.* How much $ do you want the investor to invest? How much will they get back as a return on their investment? When (and how)? Is the ROI big enough for the investor to take the risk and spend their time studying your business plan and trying to manage/keep an eye on you. Without some idea of these numbers you have no frame of reference for whether any of your products are big enough to be meaningful to the overall revenue and profit targets. You have to at least chop with an axe to get some idea of these numbers and then iterate.
If you go to an investor and say I want you to invest $10,000 or $50,000 or $1 million (or any amount) they will ask “how much are your revenues now?” And you will say zero. They will then ask “if I give you the investment you are seeking how much will your revenues be in a year, and two years, and in three years?” If you can't answer these questions the discussion will end without an investment. If you can answer these questions the investor will ask “how much profit you will make on each of these annual revenue numbers?” If you can't answer that with compelling information the investor won't be able to determine how much of your company's equity they need in order to get a ROI. If you can answer these questions the investor might then say "OK, your revenue projections seem plausible, and your profit projections seem plausible, so I will need "N" percent of your company's equity in order to get my ROI.” That would be the start of a good negotiation but before the investor wires you any funds the investor will ask "how do I know you can sell that much of your product?" To which you will say because it's better than all the other products and because you have some users who are happily using the product but you don't yet have any revenue producing sales. To which the investor will say "Sounds like you have some good ideas and a good start so come back and visit me when you have some sales where the customer actually pays for the product." And when you go back with a report on your first revenue producing sales the investor will say "Congratulations, that's exciting, come back to me when you have some more sales - and by the way, how much revenue do you think you will have this coming month, the next month, and the month after?" To which you will say, "it says right here in my spreadsheet, I will have A, B, and C revenue for the next three months". To which the investor will say "ok, if you get on that pace and trajectory, come back and see me and we'll talk about an investment." Investors like to see a plan so they can determine if the founder can operate to the plan (because they will be entrusting their investment $ to the founder’s performance, so they have to be very confident in the founder’s ability to consistently execute).
(And by the way, when you show the spreadsheet to the investor, you better be very sure those first 3-6 months are sales numbers that you will meet or exceed - because closing the investment might take roughly that long and if you miss any months during the closing process the investor will either renegotiate to account for your misses or worse yet the investor will bail out because they will figure if you can't make the early and usually lower projections on the front end, what are the chances you are going to make the later and usually much more challenging projections later in the plan?)
In the end, the purpose of the business plan is to i) set your investor's expectation in a way that you can meet and exceed their expectations but also to ii) help you figure out how to run your business in a reliable manner. Without a plan it's like building a building without a blueprint. You don't want to disappoint the investor and you don't want to disappoint yourself. You want to be able to reasonably forecast and then reasonably perform to the forecast. If you do this, the investor and other investors will probably give you more chances with more investments on ever more favorable terms. If you whiff there might not be any more help from any investors. This is your track record, build it well.
At this point, you might be thinking "wow, this is a bunch of work beyond designing and manufacturing products." To which you should be happy the light bulb came on sooner than later. Designing and manufacturing can be very complex and challenging, but so can selling and marketing (determining what to sell as well as how to promote it). The first part is "production", the second part is "distribution" (either with direct sales, or indirect sales). Unless you have a grip on both production and distribution you might only have half a chance for success. Either you need to step up to managing production and distribution, or you need someone to help you, or you need to go join another team where you can play the role you enjoy playing. This last part is really important. If you enjoy something it won't feel like work; if you don't enjoy it could become overwhelming to the point of being a significant impediment to the success of the business.
You need to find something you can not only design and build but that people will buy often enough and for a price that will give you a chance at success and happiness. No sense in kidding yourself about any of this.
In summary, you either need a) revenue producing customers before investors, or b) some very happy users before investors, and then in addition to a or b, you also need c) some very clear answers on what your revenue will be for the next 36 months or so. Without clear and fairly specific answers to questions about customers and revenue, nothing else will get you there unless you find some investor who doesn’t care about their ROI (in which case they might be a philanthropist). With a few exceptions, most investors probably didn't accumulate their $ without having some ideas about how to manage their $. So you need to have some good answers that can only be derived from good planning and analysis - almost certainly in a spreadsheet. Further, the fewer good answers you have the about these matters the more risk the investor will assume and the more expensive (to you and your company) will be the investment. More risk requires more reward; your job is to minimize the risk (for you, your company, the investor, and your customers) by building a business plan that can be reliably executed.
Net, net: you must be able to project your revenue, costs, and profit in order to give an investor any chance at determining if there is any particular likelihood of ever getting their investment back along with some return.
PS, when you call for "Veterans" to help you, you should probably acknowledge that you saw and received the help. Investors will want timely and succinct feedback on any Q&A as will anyone who might help you.
*PSS, these are the simple basics. It's a little bit like ideal vs lumped elements. Until you get a grip on the ideal it's hard to figure out the lumped. So, there are more layers to the process of building a business plan and a business, and securing investments, but this is about as basic as it gets. Having great products is great, but now your top priority needs to be figuring out how you can reasonably forecast and actually secure revenue, or at the very least get some very happy reference users - because eventually, without the topline (revenue) there is no chance at a good bottom line (profit), and without the prospect of a good bottom line there isn't much chance of providing an investor with a ROI. However with a clear and concise view of the future topline and bottom line - and how they will be attained - there is a chance for an investment.
Revenue
- SG&A
- COGS
Profit
It all starts with revenue and flows from there to profit, to a potential ROI for the investor, to a chance for you to get an investment.
PSSS, if this was easy, everyone would be doing it