Hackaday Prize Entry: Dr. DAC

June 1, 2015 by Brian Benchoff 46 Comments

The theme of this year’s Hackaday Prize is. ‘build something that matters.’ A noble goal, but there’s also a second prize – the Best Product prize – that is giving $100k to one lucky team who can appeal to people with open jaws and wallets. It’s a fabulous prize that also includes a six month residency at the Hackaday Design Lab, but right now there aren’t many contenders for this part of The Hackaday Prize.

[drewrisinger]’s DrDAC USB Audio DAC is one of those project that’s in the running for the Best Product prize. He’s solving the problem of terrible low-quality built-in soundcards that seem to be everywhere. Yes, it’s a simple idea, but the execution is great.

The electronics for DrDAC are pretty much what you would expect for a DIY audio sound card; A PCM2706 takes USB audio and sends it out over I2S. A PCM1794 converts the I2S to analog audio, and an OPA2836 amplifies it and sends everything out through a 1/8″ jack or a pair of RCA plugs.

[drewrisinger] started DrDAC as a school project, and after receiving the PCBs, he noticed a problem. MultiSim’s footprint for a TQFP-32 package was too small, meaning the IC simply wouldn’t fit on the board. It was too late in the semester to order a new board, meaning some sort of rework needed to happen. [drew] fixed this problem by soldering jumper wires between the pads to the leads of the chip. Yes, it looks crazy, but apparently it works. You can check out a video of that whole process below.

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DSP 01: Real, Legit Audiophile Goodness

February 27, 2015 by Brian Benchoff 22 Comments

About six months ago, we saw [tshen2]’s work on the DSP 01, a 2-input, 6-output DSP and crossover for extreme audiophiles, and we’re not talking about oxygen free rooms here. The DSP 01 turns a USB audio output into six outputs that will give you perfectly flat eq across bass, mids, and highs, integrates with a 6x100W amplifier, and compensates for room noise. There was a huge update to the project recently and [tshen] is more than happy to share the details

Getting to this phase of the project hasn’t been without its problems. To get the DSP communicating to a computer through a USB port, [tshen2] found a potential solution in the CP2114 USB to I2S Bridge. This device should function as a USB audio sink, translating digital audio into something the DSP understands. This chip did not work in [tshen]’s design. The CP2114 simply does I2S wrong; the I2S spec says the clock must be continuous. This chip implements I2S with a SPI, firmware, and a few other things, making it incompatible with to-spec I2S.

While there was some problems with getting audio in to the device, the core of the device has remained unchanged. [tshen2] is still using the Analog Devices DSP, with the interesting SigmaStudio being used to compensate for the frequency response of the room. This real, legit, science-based audiophile territory here, and an impressive development for a field that – sometimes understandably – doesn’t get the respect it deserves.

I2S Audio And SPI Display With An Ethernet Module

April 23, 2014 by Brian Benchoff 16 Comments

LCD [kgsws] is working on a small project that requires some audio and a display of some sort. While this project can be easily completed with a bigish microcontroller or ARM board, he’s taking a much simpler route: the entire project is built around a cheap router module, giving this project amazing expandability for a very meager price.

The router module in question is the HLK-RM04 from Hi-Link, commonly found via the usual Chinese resellers for about $25. On board this module is a UART, Ethernet, and a WiFi adapter along with a few GPIO pins for interfacing with the outside world.

[kgsws] is using the native SPI pins on this module to control the clock and data lines for the tiny LCD, with a GPIO pin toggling the chip select. I2S audio is also implemented, decoded with an 8-bit DAC, the MCP4801.

It’s an extremely inexpensive solution for putting audio and video in a project, and since this board has Ethernet, WiFi, and a few more GPIO pins, it’s can do much more than whatever [kgsws] is planning next.