Updated Tue, Apr 13, 2010 by Space Junkie
Step Four: Get A Data Interface
The next item used in invention is called a Data Interface. It's kind of an "okay, now you can invent modules in this race's category" module. The various data interfaces used for module invention with each race are:
These are pretty cheap, on the market in Jita, because they are not expended or used up in any way, with use. Once you have one, you can always use it to run invention jobs of that category. Make sure that you don't buy the 'ship' or 'tuner' versions of these, by accident, as they are used for ship and rig invention, respectively.
Step Five: Get Datacores
Datacores are a commodity item produced by special agents. They are best purchased in Jita, or if you have R&D agents you can get them directly from them. Each invention job attempt consumes an amount of datacores. Unlike the data interface, they are used up in the attempt. This expenditure takes place whether the invention attempt succeeds or fails.
In our continuing example, we see on the Salvager I Blueprint's information that it requires two kinds of datacores: Electromagnetic Physics and Electronic Engineering. These are, of course, the skills that you need to train in order to invent this module. Which are the skills needed to procure those datacores from R&D agents. None of this is coincidence. It's fairly easy to set up a mass invention business, based entirely around things that you produce.
Because invention jobs often involve several attempts, it is a good idea to get a bunch of datacores at once. In our example, we might buy 20, each, of Electromagnetic Physics and Electronic Engineering datacores, so that we can try ten invention attempts.
Step Six: Run The Job
If all of your ducks are lined up in a row, find a station with available invention slots by clicking on your 'Science & Industry' button, selecting the 'Installations' tab, and setting 'Invention' as the option under the 'Activity' menu. Get all your stuff into that station.
Right click on one of your max-run tech one blueprint copies, and select invention. Don't worry about any of the options, for now. Just click accept, and assuming you've done everything right, you should be able to click 'Accept' and the job will be up and running. Each invention job takes a variable amount of time. For most modules, it will only take a few hours for a job to run. The slots used on your character are lab slots, the same that you would use for researching or copying blueprints.
Once the job has finished, you must use your Science & Industry window to complete the job, just like any other industry-related job. For each invention job that you finish, a window will pop up to indicate whether your attempts have been successful or not. Eventually, one or more will succeed. Congratulations, you have your first tech two blueprint copy!
If you did everything correctly, it should have ten runs on it, and have a material efficiency of -4. You can sell the blueprint on contracts, or if you're up to the task, assemble the tech two module yourself. Future guides will cover the process of actually making tech two goods, in greater detail.
Odds and Ends
When inventing modules with the related skills (see three) trained only to I, your base chance of success is about 42% per attempt. With those skills trained to IV, the chance improves to a little over 48% per attempt. The price of the items involved includes this ~50% loss rate. Just be sure that when you are calculating your profit margin, you take this into account.
When you are installing an invention job, you have the option of including a 'base item'. A item means a tech one or "named" version of the module that you are trying to invent. That item will be consumed, but will raise the chance of success by a bit. It usually doesn't make much sense to futz around with these, as they rarely improve the chance by enough to offset their cost.
You also have the option of including a Decryptor. Decryptors are colorfully named special items that may modify any of the following when included as an invention ingredient: chance of invention success, material efficiency or production efficiency of any BPCs produced, or number of runs. These are not recommended for use with modules because of their high cost, as they are expended when used. Some have their uses when inventing certain kinds of ships, however.
A good spreadsheet is really a must-have, in order to figure out whether you are actually making money. A successful invention business can make you richer, or at the very least allow you to supply yourself and perhaps your corporation with at-cost tech two modules.
I hope this guide made inventing modules a little bit clearer for you. I wish you the very best for your endeavors in EVE Online.