Moore’s law may not be as rigid as we once thought, because chip manufacturers are trying to install more and more transistors in specific areas of silicon. But in the past few decades, it has been surprisingly consistent and has produced many chain effects. As the speed of the computer becomes faster and faster, everything else related to it becomes faster and faster. Garbage bins tend to fill up quickly with various computer peripherals and components that may work well but cannot keep up with speed. [bonsembiante] has an old ADSL router, which is out of date due to the changes of the times, but he didn’t throw it away, but turned it into a guitar effect pedal.
The principle behind this construction is that the router is essentially a Linux machine and fully supports alsa. Of course, this means refreshing custom firmware, which is not the easiest task, but once the device adds sound support, it can interface with the USB sound card. An additional C + + program was created to process the actual audio received from the guitar and sound card. In this demonstration, [bonsembiante] has programmed a ring buffer and fed it back to the output to achieve an echo effect, but any effect or many effects may be programmed.
For anyone looking for the source code of the signal processing that the router is performing, it will be listed on a separate GitHub page. However, if you do not have this particular model of router in your parts box, there are more ready-made Linux machines that can do this.