If you have old USB headphones you can easily transform them to a USB sound. This card can be helpful during testing of home built devices connected to the speaker or microphone ports on the PC (for example A proof of concept of a simple sonar and Constructing a homemade microphone).
I used broken Audio 655 DSP headphones with working electronic inside. They have below features:
- Powered from USB.
- Stereo output.
- Built-in microphone.
- Mute/unmute switch.
- Volume up/down switches.
- Power on LED indicator.
View of disabled headphones. Two PCB visible: one that was in the USB key, and the second that was in the headphones. Speaker and microphone were desoldered.
Both PCB were soldered together.
The USB sound card was visible on the computer when connected by USB cable.
A glue was applied on both sides to prevent shortcuts or other damages of the connections.
To fasten the USB PCB part, a thick wire was soldered to the connections of the PCB and USB socket. Later it was soldered to the stripboard.
The capacitor was desoldered to made backside of the PCB flatter (better physical fixation to the stripboard), later it was resoldered on the other side of the PCB (pay attention to polarization, incorrect connection may lead to an explosion of the electrolytic capacitor!). LED and all switches were also desoldered and cables were soldered to the places where those elements were.
Buttons and LED were soldered to stripboard and connected by using soldered previously cables.
Bottom of the stripboard was cleaned by using isopropyl alcohol and protected by using plastic spray paint.