timer_entropyd feeds the /dev/random device with entropy data (random values) read from timers. It does this by measuring how much longer or shorter a sleep takes, since this fluctuates by a few microseconds every time. The time for a sleep jitters due to the fact that the frequency of the clocks of the timers change when they become colder or hotter. This program does not require any extra hardware. It produces around 500 bits per second. This program is also usable with virtualized systems.
Spectra is a simple tool designed to aid in evaluating the quality of random numbers generated by TRNGs and PRNGs. It does this by counting the occurrences of characters within a given input file to help detect perceived bias, and then visualizes the data as colored (or black and white) pixels in an image file to aid in detection of repeating patterns. As the human mind is exceptionally good at picking up on patterns that might otherwise be difficult to detect mathematically, Spectra allows the user to rapidly make a determination on the repeatability of numbers generated from the suspect RNG.