This project is about a device that is able to switch between different audio sources, i.e. from different music receivers and players. As a side feature, the product is able to display and visualize the current audio signal that passes throug via a dedicated VU-meter and/or FFT mode.
The audio signal switching is accomplished by using 3 SPDT relays that are connected in a tree-like fashion.
The first relay starting from the bottom of the "tree" switches 2 sources while its sibling another 2 sources. The 3rd relay on the top does the switching between the two siblings.
If the system requires additional audio sources it is still possible to add a 4th relay, either on top or at the bottom of the tree, starting a new leaf node.
The 2 stereo channels are read using the ADC subsystem of the microcontroller. The sampling frequency is around 19khz, which is more than sufficient for signal visualization porpuses.
Two modes are available: FFT and VU-meter; both have a couple of appearance settings to match users' taste.
display: git pull -s subtree deasplay master
For code licensing, please have a look at the source codes.
Version 0.2 - Work In Progress! Optimizations and code cleanup New display HAL and drivers (deasplay) Version 0.1 Initial Version