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Data Acquisition System for the Raspberry Pi

Former Member

In the last year, we've been impressed by the Raspberry Pi.  We believe that its capabilities and price point are a world changer.

 

We would like to bring to market, a flexible, low-cost ($35) data acquisition system for the Raspberry Pi.   Our system brings an 8 channel, 200 ksps, 10 bit analog to digital converter to the platform.  Notable hardware features include a programmable voltage reference, and user selectable AC or DC coupling.  There are several software solutions available to acquire data, including a java based (multi-platform - Windows, Linux, Mac OS) Remote Scope Application, a Remote Spectrum Application, as well as command line applications to take measurements.

 

We think that the Raspberry Pi combined with the RAS-DAS-1 provides a low-cost way for students to conduct experiments and put the fun back into science and math.  Towards that end, we are introducing an accessory card for the data acquisition system geared towards capturing audio data.  It is called the Audio explorer, and includes 4 electret microphones (with the accompanying high-gain amplifiers), and audio input jacks to easily bring audio data into the RAS-DAS-1 and the Raspberry Pi.

 

With this system, students can perform science experiments such as measuring the speed of sound, use trigonometry to determine the direction a sound comes from, or determine how far away a wall might be by listening for echoes (using a type of sonar).

 

We are introducing a kickstarter campaign to bring this technology to market, and would appreciate any assistance you might provide in spreading the word.

 

http://www.kickstarter.com/projects/254558907/data-acquisition-system-for-raspberry-pi

  • @ Dennis - there is a lot you aren't saying. The hardware spec (what there is of it) is so last millenium ! (10 bit and (since you don't say different) 200ksps across all 8 channels)).

     

    A £3 - 7 ARM cortex processor from ST or NXP has 12 bit 1Msps (or faster) ADCs (three on some of the ST parts).

     

    If your device is for audio why don't you use decent audio ADCs (16 or 24 bit and at least capable of operating at standard frequencies (48kHz and 96 kHz per channel)).

    You can buy stereo ADCs from Farnell (24 bit 192 kHz per channel) for £0.60 each, 4 of those and a little FPGA (or possibly one of those nice XMOS $3 multicore processors) gets you an 8 channel simultaneous sampling analogue conversion engine for under $10 parts cost in 100 off quantities.

     

    Sorry - it doesn't look like much for $50k.

     

    MK

  • in reply to michaelkellett

    I agree wit Michael, that's why I was asking for the schematics to see where is the "value." Also about the "enclosure," two rectangles of plastic with stand offs ?

     

    No pun/offense intended but it looks more like trying to ride on the Pi hype than putting together something original and useful.

     

    My .02

    -J

  • Perhaps wattminder instruments need to communicate this in a better way.

     

    The purpose of this product is to provide general purpose analog data acquisition to the Raspberry Pi at a good price / value.  It is intended for people who do not want to build their own board, and want to use a powerful computer like the raspberry pi to get data and  process it.

     

    The price for the data acquisition card is $35 (the same price as the raspberry pi).  (The $50K is the target goal in order to go to production, and have the boards made in quantitty - fabricated, assembled, tested, etc.).

     

    The system is more than just an ADC chip.  It is a system which provides a programmable reference voltage (as well as other sources for VREF), AC/DC coupling capability, input protection circuitry, external power inputs (so that you could provide a quiet power supply to it), an a utility op-amp with gains of 1x, 2x, 4x, and 8x.

     

    All of this is in the same form factor as the Raspberry Pi.

     

    There is also software which grabs data across a network and plots it (which makes it like a hackable oscilloscope).   (Since the software is all within the raspberry pi environment, this makes debugging much easier than for instance connecting up an arduino nano, and a raspberry pi, and debugging between the two).

     

    The enclosure is a different story.  I think it's quite an elegant looking device, which is composed of a top an bottom with easy access to the raspberry pi via the sides.  The open sides provide lots of ventilation.  The enclosure provides space for 2-3 cards, and can be expanded as needed.

     

    When it comes down it, value is in the eye of the beholder.  Chips themselves are just sand and plastic, with a lot of processing.  This system provides value for those who don't want to bother with making their own boards, soldering surface mount chips, testing/debugging (i.e.: dealing with solder shorts, etc.), as well as providing everything in a neat package.

     

     

    Tony

  • in reply to Former Member

    @Tony,

     

    Prompted by your posting I had a look at Wattminder's website - they don't publish a schematic but from the picture of the board I'm even less enthusiastic. They make  a big thing about audio but the basic data acquisition system is just no good for audio. A variable voltage reference and variable gain (not clear if adjustable per channel by software) is just no substitute for using an adc designed for audio (16 bits or more, standard sampling rates, simultaneous sampling, anti-aliasing filters) . As I mentioned earlier such adcs are cheap enough.

     

    A company looking for $50k investment should have a product that's a bit more state of the art.

     

    MK

  • i want to design a basic spectrum analyzer using raspberrypi.so i needed an adc that can be connected to raspberrypi.Which adc i shall use?

  • in reply to Former Member

    More information is needed to answer your question:

     

    frequency range (max frequency sets the sampling rate required and frquency resolution sets the number of samples per spectrum)

    resolution (no of bits) or dynamic range (dB)

    will you make your own pcb

    what interface will you use to the Pi

     

    MK