Mung bean sprouts are a very popular food throughout Asia, as they are nutritious and extremely easy to grow. While you can certainly purchase these bean sprouts at your local markets, you can also take advantage of their easy cultivation to grow your own. Doing so is affordable and doesn’t take much time or equipment, but Nico Pretorius’ automated bean sprouter will make the process even easier.

Mung bean sprouts are seeds that are going through the germination process, so cultivating them is a matter of encouraging that germination. There are different techniques in use around the world, but the most efficient involves soaking mung bean seeds in water every few hours. After a few days, you get edible bean sprouts that are suitable for a wide range of culinary dishes. This device automates that watering process to eliminate almost all of the manual labor associated with cultivating bean sprouts. 

Achieving that is as simple as activating a water pump according to a preset schedule. This tutorial calls for the use of an Arduino Uno, but any other Arduino board would work equally as well. The Arduino uses a real-time clock (RTC) module to keep track of the time and then activates the water pump through a relay module. The device receives feedback through a DHT22 temperature and humidity sensor and displays relevant information on a 16×2 character LCD. 

The entire unit is 3D-printable, which means that you need to take into account food safety guidelines for 3D-printed parts. PLA is food safe on its own, but the nature of 3D printing allows for bacteria growth in the small ridges between layers. For that reason, it is best to coat the 3D-printed parts in a food safe epoxy. Once you do that, you’ll be able to grow bean sprouts at home without any work.