We all want to be able to communicate with each other in total privacy. So we need lots of good random numbers to do that using cryptography. And true random numbers are the best. Unfortunately it is almost impossible to prove that a commercial true random number generator (TRNG) hasn’t been weakened by the government. We show how to make entropy sources using simple and commonly available components like Zener diodes and web cams. These can then be the foundations of your own TRNGs that will work really really well. Or in a nutshell, something like the things below. So why build one?