how much of the OpenBCI board can be moved onto a smartphone?

Comments

• wjcroft Mount Shasta, CA

  January 2016

  Colin, hi.
  
  The easiest way to go may be with what is called an OTG (On The Go) usb adaptor for your smartphone. This can plug into the OpenBCI dongle, which can then talk to the OpenBCI mainboard.
  
  http://openbci.com/forum/index.php?p=/search&Search=otg
  
  Your original question sounds like you might be considering lashing up an ADS1299 chip to an existing smartphone processor board. But my guess is that would be challenging. One consideration being noise isolation for the microvolt level signals involved with EEG. The OpenBCI mainboard has a number of design features which reduce noise. If you lashed an ADS1299 onto a smartphone processor board, this becomes more difficult.
  
  Also see this post on the Community board,
  
  http://openbci.com/community/openbci-with-android-as-graduation-project/
  
  Which uses interfaces a breadboarded Bluetooth 3.0 chip to the OpenBCI mainboard. This then can talk directly to most phones with Bluetooth 3.0 support.
  
  ---
  
  Found your website, cool.
  
  https://www.emfcamp.org/
  
  I guess another name for it would be "the UK camp for Makers". A "field" full of Makers.
  
  William
  
  
• Colin

  January 2016

  Thanks William.

  
  

  My very naive understanding of the OpenBCI board is that the ADS1299 has specialised signal processing capabilities that can't be replicated by the processors on a smartphone.

  
  

  Equally naively, though, I'd thought that the PIC32 was less capable than the processors found in newer smartphones.

  
  

  Do you know of any beginners' guides to the OpenBCI architecture?  (I found the documentation at http://docs.openbci.com/hardware/01-OpenBCI_Hardware too schematic for me to understand.)

  
  

  Best,

  
  

  Colin

  
  

  p.s. I wish I could take credit for the EMF camp's website, but we just ran one set of workshops there.  The camp was so much fun, that my children and I also attended CCC this past August in Germany.

  
  
• wjcroft Mount Shasta, CA

  January 2016 edited January 2016

  Colin, hi.

  
  

  The ADS1299 is TI's EEG analog to digital converter, documented here,

  
  

  http://www.ti.com/product/ADS1299
  

  
  

  You are correct, it can be interface to any uC. And yes your smartphone processor has way more horsepower than the mainboard uC's used in OpenBCI. If you look at the TI pdf you can read about the recommendations for star grounding, ground planes and such that reduce noise levels. This would be challenging to accomplish with an ADS1299 somehow lashed onto a smartphone.

  
  

  Which is why I mentioned previously, using the OTG adapter to connect your phone to an OpenBCI. Or the other approach mentioned, modifying an OpenBCI mainboard to speak Bluetooth 3.0. Which your phone would understand.

  
  

  The Forum section this thread is on, is devoted to various Makers who are using the ADS1299 with other uC platforms. You may find some related projects there,

  
  

  http://openbci.com/forum/index.php?p=/categories/other-platforms
  

  
  

  Best,

  
  

  William
• Colin

  January 2016 edited January 2016

  Thanks William.

  
  

  If I understand the TI PDF correctly, I'd need to keep capacitors on the board as well.

  
  

  re: the OTG adapter, re-reading my original post, I think that I didn't explain the workshop idea well.  I'm wondering whether it's possible to run a workshop in which participants make their own simple BCIs, using their smartphones, and as little additional hardware as possible .

  
  

  At this point, I think that this is probably too ambitious: 

  • the price of ADS1299 alone already makes this a bit borderline for a casual workshop.  
  • more positively, Peabody's original washer electrodes seem like a great way of keeping costs down.
    
  • further, the capacitors wouldn't add much to the cost.

  Off-hand, do you know how much of a step down in performance you have to take to get an EEG front-end that's significantly cheaper than the ADS1299?

  
  

  Best,

  
  

  Colin
• wjcroft Mount Shasta, CA

  January 2016

  Colin, hi.
  
  If you are wanting to do a short workshop (a few hours or a day), how would you manage the surface mounting / soldering of the ADS1299 onto your circuit board? There are some TQFP adaptors / Schmartboards that might work, but what you are envisioning sounds like it will take more time than would be available in a short workshop format. You really need the ground planes and star grounding to avoid noise issues. Typical prototype breadboards would likely not work well with the ADS1299.
  
  You also would likely not need all 8 channels. Have you looked at the OpenEEG kit from Olimex?
  
  Inexpensive cup electrodes can be found on the web. Less than $10 each.
  
  Have you considered networking with the Hack the Brain folks there in the UK? They might be able to loan you some OpenBCI's for the duration of your workshop.
  
  http://openbci.com/community/hack-the-brain-uk-control-your-smartphone-by-winking/
  
  
  
• Colin

  January 2016

  Thanks William.

  
  

  Very good suggestion about Hack the Brain, which I didn't know about.  I'm hoping to meet some of the neuro people at London Hackspace later this week, and will ask if they're in touch with them.

  
  

  Thanks also for the steer on the OpenEEG, which I didn't know about, and the electrode kits.  That might be a manageable price (although I have to admit, I am becoming attached to the 'hacky' feel of the washers).

  
  

  At a hacker camp, soldering in a workshop increases complexity, but can work.  (One of our favourite workshops at CCC involved building a bone conduction 'skull radio' that converted output from a smartphone's audio jack to vibrations in a rod held between your teeth.)

  
  

  I've just discovered Intantech's AFEs, but they seemed more expensive than the ADS1299.

  
  

  C+