SHAMP - simple headphone audio mixer project
Shown below is the SHAMP Model 1 which features two 3.5 mm stereo inputs and one 3.5 mm stereo output.
There are a lot of raw circuit board hacker/prototype devices with headphone jack audio outputs. Devices to play songs, to speak words, to synthesize sounds, and many similar devices for numerous audio applications.
I wanted to build a system that mixed the outputs of several of these devices. I looked for a simple 'Sparkfun-caliber' hacker-ish bare circuit board audio mixer without success. Here are some things I did find:
- Urban DJ - discontinued?
- iRig MIX - big, requires external power
- failed Kickstarter - interesting WiFi feature
- failed Kickstarter - simple with nice finish
- Instructables DIY project - classic Altoids tin casing
After reading the Instructables article linked above, I looked for a set of parts that I could use to build something like the Altoids tin mixer. One key piece I found is the Papilio Audio Wing which has 2 audio jacks, seemingly reasonable resistors, and breakouts for the TRS audio wires. I combined this with several other Sparkfun parts to create the SHAMP Model 1.