We bring to you the audio card (for the Raspberry Pi) which seemed impossible, but now it is done! Push your projects further into un-trodden territory - further then others have gone before.

Whilst this gadget works with the Raspberry Pi, it represents an innovation in the realm of embedded systems. The innovation is at a hardware level, in audio signalling, giving us the ability to retrofit these systems with more then their typically quoted two channels of audio in and out.

Audioinjector Octo sound card - RCA breakout

This sound card features crystal clear 8 channel output audio, with 6 channels of input audio. Unlike other multichannel solutions, this surround hat only uses the GPIO I2S bus for audio. It doesn't use USB nor does it use HDMI.

Audioinjector Octo sound card - powered balanced breakout

It has the capacity to provide powered balanced lines because the system is differential. This image shows the professional level output balanced breakouts. A similar board with provided for the six input balanced lines.

Audioinjector Octo sound card - make your own breakout.

The sound card is designed to be customisable. You can design your own break out to suit your needs. The break out headers are available on github as a KiCad project to aid your designs.

Our previous kickstarter success was delivered on time, working and with support. Support this campaign which builds on the same foundation.

For a scoop on the story behind this product, check this XDA post.

Stretch goal #1 at $10 000 (done)

Our first stretch goal (now achieved) will improve performance by introducing a second clock oscillator. This second oscillator will give improved performance at particular sample rates.

Stretch goal #2 at $12 000 (done)

Open hardware the RCA breakout boards. We have pushed to github the KiCad schematics and PCB layouts for the RCA breakout board. This will be a good reference if you want to design your own line breakouts.



Stretch goal #3 at $14 000 (done) Open hardware the balanced line breakout boards. We have pushed to github the KiCad schematics and PCB layouts for the TRS breakout boards. This will be a good reference if you want to design your own balanced line breakouts. Stretch goal #4 at $16 000 We will provide 3D printable panel templates (possibly on thingyverse). You will be able to print these panel plates to use in boxing your awesome devices ! Stretch goal #5 at $20 000 We will provide you with physical aluminium panel plates as part of your delivery ! Nothing beats the real deal ! Shipped to your door.

How do you use it ?



Nothing fancy, just plug it in and set it up like you would any other GPIO sound card. It is setup to run out of the box as the default sound output and input. That means that all of your applications will use it by default.

Example applications

Professional audio recording (with 6 balanced inputs)

Multichannel output for your projects.

Car audio front/back fading.

Active crossovers, up to 8 way, or 2 speakers each 4 way.

SDR, processing many channels at the same time.

Surround sound output for your media centre.

Projects we didn't imagine you would implement !

Implement Active Crossovers

For a home theatre, plugin to your surround sound amplifier.

Auto front rear fading using GPIO control (suggested by Paul & inspector71)

Stretch Goals

As we have made our goal, we would like to introduce some stretch goals. If you haven't heard, stretch goals are new goal targets which (if accomplished) introduce new elements for free into pledges. We would like to hear from you (backers) what you would like to see as future stretch goals.

Specifications

Audio output : 8 channels

Audio input : 6 channels

Sample rate : 96 kHz

Resolution : 24 bit

Codec : CS42448 (manufacturer page)

Clocking : Chip oscillator driven for low jitter performance.

Extra Requirements : None, just plug onto your Pi.

Software Requirements : Will be part of the stock Raspbian distribution, with drivers uploaded to the official Raspberry Pi git tree. This is similar to the previous hardware we have released and the drivers ship with standard Raspbian ready and working. We also provide setup scripts on the support forum.

Support : The raspberry Pi forum, stackexchange and this Audio injector specific forum.

Specifications : balanced breakout

Add to the previous specifications the following :

8 output and 6 input 1/4" balanced sockets.

20 pin header for both input and output, which includes differential signals and power.

Mute pin for output header.

Using metallized film capacitors for optimum linear performance.

Professional audio line levels (around 1.5 V peak).

Threaded connectors with nuts for face plates (panels).

Output breakout dimensions : 190mm x 45mm

Input breakout dimensions : 145mm x 35mm

Previous kickstarter campaign

Previously the Audio injector was successfully released on Kickstarter. The Audio injector was delivered on time (one month after the end date of the campaign).

Back this project and save

From experience, Kickstarter allows you to pickup the product at a much reduced rate (our previous product was around 15% to 20% cheaper on kickstarter, mainly because of the Amazon and Ebay fees).