Best answer: The easiest way to get a Sodium Diode is by crafting it with 40 Ferrite Dust and 40 Sodium Nitrate. Unfortunately, you'll still need to find its blueprint beforehand, and that can be the most time-consuming part.
Where to get Ferrite Dust and Sodium Nitrate
Ferrite Dust is one of the most common elements you'll find in No Man's Sky, as it can be found an every planet. It's obtained through mining rocks on the surface. As for Sodium Nitrate, it's a bit rarer, but still easy to get. If you see glowing yellow crystals on a planet, you'll be able to harvest Sodium Nitrate from these with an advanced mining laser. Because these aren't as common to come by as Sodium is, just collect some Sodium and place it into a Refiner. Two Sodium will yield one Sodium Nitrate.
How to find a blueprint
This is the trickiest part. Even if you have the ingredients to craft a Sodium Diode, you won't be able to actually do so until you find a blueprint for it. Blueprints can be found at random in Manufacturing Facilities. These facilities will be guarded by Sentinels, so stay in your starship to blast the doors open before entering. If you're having trouble finding a Manufacturing Facility, build a Signal Booster and search for Secure Frequencies.
There is no surefire way to get a Sodium Diode blueprint from one of these facilities. The blueprint you get will be random, which makes this method a shot in the dark.
Buy from merchants
If you don't want to put in the time, you can also by Sodium Diodes from merchants and at the Galactic Trade Terminals aboard space stations. Again, it's not guaranteed that Sodium Diode will be available to purchase every time. It's random.
Take to the stars.
No Man's Sky is an ambitious space exploration sim from Hello Games. With the most recent updates, you can catalogue uncharted life on foreign worlds, build a home base with your friends and more. The sky isn't the limit anymore.
