I would like to control to some extent the robotic movement of something I'm building using EEG readings, basically developing a brain-computer-interface. The price for EEG equipment that I've found so far is very expensive (roughly £1000)
Would anyone know about more affordable EEGs or alternative methods of measuring brain signals?
johnwasser:
Consumer brain–computer interfaces - Wikipedia
Seen this already.
I don't think you got my question. I want to know where i can purchase a cheap EEG to build a brain computer interface with, not to but a pre-built BCI that requires the company's own specialized software as the items in your link are. The problem with using any of that stuff is their devices are built in a way that their own software can interpret and present information from the readings whereas I would like to analyze the readings myself from an EEG device.
mrxyz:
I would like to control to some extent the robotic movement of something I'm building using EEG readings, basically developing a brain-computer-interface. The price for EEG equipment that I've found so far is very expensive (roughly £1000)Would anyone know about more affordable EEGs or alternative methods of measuring brain signals?
I don't know crap about this but I am happy to do some research as it is interesting. OK, what is the technique for EEG?
In conventional scalp EEG, the recording is obtained by placing electrodes on the scalp with a conductive gel or paste, usually after preparing the scalp area by light abrasion to reduce impedance due to dead skin cells. Many systems typically use electrodes, each of which is attached to an individual wire. Some systems use caps or nets into which electrodes are embedded; this is particularly common when high-density arrays of electrodes are needed.
Electrode locations and names are specified by the International 10–20 system for most clinical and research applications (except when high-density arrays are used). This system ensures that the naming of electrodes is consistent across laboratories. In most clinical applications, 19 recording electrodes (plus ground and system reference) are used. A smaller number of electrodes are typically used when recording EEG from neonates. Additional electrodes can be added to the standard set-up when a clinical or research application demands increased spatial resolution for a particular area of the brain. High-density arrays (typically via cap or net) can contain up to 256 electrodes more-or-less evenly spaced around the scalp.
Each electrode is connected to one input of a differential amplifier (one amplifier per pair of electrodes); a common system reference electrode is connected to the other input of each differential amplifier. These amplifiers amplify the voltage between the active electrode and the reference (typically 1,000–100,000 times, or 60–100 dB of voltage gain). In analog EEG, the signal is then filtered (next paragraph), and the EEG signal is output as the deflection of pens as paper passes underneath. Most EEG systems these days, however, are digital, and the amplified signal is digitized via an analog-to-digital converter, after being passed through an anti-aliasing filter. Analog-to-digital sampling typically occurs at 256–512 Hz in clinical scalp EEG; sampling rates of up to 20 kHz are used in some research applications.
So we need a way to connect to your skull full of mush (electrodes), differential amps, and probably a very high resolution many channel ADC, right?
Here is a cheap commercial machine:
The electrodes are available on eBay too. That is interesting because otherwise it would be difficult to get these.
http://www.ebay.com/itm/ten-pcs-silver-plating-electrodes-electrode-for-CONTEC-EEG-machine-KT88-Series-/320774845114
http://www.ebay.com/itm/ten-pcs-of-silver-plating-electrodes-for-CONTEC-EEG-machine-KT88-Serie-2400-3200-/160934365730
Now for the important bits. TI seems to be big in the EEG/bio-measurement semiconductor market. They have multi-channel high-resolution highly integrated systems for exactly what you are looking for. Check these out:
Free Samples are available on all these parts. (side note: I love free samples. 
) My advice to you is get the samples, do a deep dive, become an expert on this, and get back to us in Exhibition / Gallery in a week or two when you have your project complete. 8)
mrxyz:
I want to know where i can purchase a cheap EEG to build a brain computer interface with
Did you check out the Open EEG project?
http://openeeg.sourceforge.net/doc/
You can get the boards, assembled, for 125 Euros.
Since you want to do your own interface you can probably skip the digital card and just get the analog card for 75 Euros.
johnwasser:
Did you check out the Open EEG project?
HOLY CRAP. I was out for dinner and thinking this problem over in the car and I sort of joked with myself that I wished there was an "Open EEG" project since there are some many "Open X" projects out there these days. I didn't even look, I just dismissed it as being implausible. That's great. Now I have to start searching to see if there is Open Cruise Missile or Open Mars Rover available yet.
And be sure to read the disclaimers about hooking electrical devices
to your body.
oric_dan:
And be sure to read the disclaimers about hooking electrical devices
to your body.
What could possibly go wrong?
There's a kickstarter project I've seen that's developing an EEG thing too, from memory.
There it is: http://www.kickstarter.com/projects/86514518/diy-arduino-eeg?ref=live
What could possibly go wrong?
Did you even look at the disclaimers?
Since gov't agencies have stringent safety tests for such devices,
there are probably dozens of ways they can go wrong. Start here,
Also, as a trained engineer, I'd not much trust a guy's competence who
makes circuits like that kickstarter thing. What a friggin mess. It's hardly
gonna pick up 5 uV signals. Looking at it, it's very unlikely he even has
the correct opAmps.
oric_dan:
What could possibly go wrong?
Did you even look at the disclaimers?
Note to self: remember emoticons. No matter how ridiculous your sarcastic post.
aarondc:
What could possibly go wrong?
Agreed nothing, especially when you consider that the OP is a school kid who is not fully conversant with ohms law ( other posts ) and wants to build a arduino brain controlled set of super human strength robot arms fitted in a backpack then .....
I'll put the Darwin Awards people on standby then.
Grumpy_Mike:
aarondc:
What could possibly go wrong?Agreed nothing, especially when you consider that the OP is a school kid who is not fully conversant with ohms law ( other posts ) and wants to build a arduino brain controlled set of super human strength robot arms fitted in a backpack then .....
I'll put the Darwin Awards people on standby then.
Looking forward to the video.
How about this brain-computer interface using an AVR microcontroller.
http://people.ece.cornell.edu/land/courses/ece4760/FinalProjects/s2012/cwm55/cwm55_mj294/index.html
@JoeN - I think our definition of 'affordable' is quite different 
Im at college and electronics/robotics hasn't been taught to me but I'm well versed in programming so self-teaching myself electronics/robotics. I can buy this but the risk is quite high as I wouldn't want to attach the wrong wire in the wrong place and throw £1.4k down the toilet.
@johnwasser - that OpenEEG sounds interesting though I'll need to have a look at whether my current ability will allow me to dive straight into building that.
@grumpy_mike - I think you need to lose some arrogance, and please don't reply on my posts again.
@BillHo - Will check that out!
@grumpy_mike - I think you need to lose some arrogance, and please don't reply on my posts again.
I will try, because you seem to be very ungrateful about all the stuff I have done for you so far. Diagrams I have especially drawn for you, you seem to ignore. And you seem to want to stick to your wrong views and argue that you are right rather than to actually learn. So when you actually start to know something then maybe you will be in a position to appreciate help. However, I will not stand by if you or your repliers start spouting untruths the reputation of this as a no BS forum needs to be maintained. Maybe when you grow up you will learn that when someone knows something that you do not, and they try and educate you about that fact, then it is not arrogance, most people call it education.
Grumpy_Mike:
@grumpy_mike - I think you need to lose some arrogance, and please don't reply on my posts again.
I will try, because you seem to be very ungrateful about all the stuff I have done for you so far. Diagrams I have especially drawn for you, you seem to ignore. And you seem to want to stick to your wrong views and argue that you are right rather than to actually learn. So when you actually start to know something then maybe you will be in a position to appreciate help. However, I will not stand by if you or your repliers start spouting untruths the reputation of this as a no BS forum needs to be maintained. Maybe when you grow up you will learn that when someone knows something that you do not, and they try and educate you about that fact, then it is not arrogance, most people call it education.
Yes indeed, you have to try and protect noobees from doing really really
stupid things, whether they want to listen or not. It takes about 1-second
for someone with training in electricity and electronics to tell when
someone else really needs some guidance.
mrxyz:
@JoeN - I think our definition of 'affordable' is quite different
Im at college and electronics/robotics hasn't been taught to me but I'm well versed in programming so self-teaching myself electronics/robotics. I can buy this but the risk is quite high as I wouldn't want to attach the wrong wire in the wrong place and throw £1.4k down the toilet.
You didn't read what I posted. What I said is you are going to have to buy the electrodes probably and posted a link to a reasonable set of electrodes. I then said build the whole rest of the kit out of samples and pointed you at TI which seems to have an integrated solution on a chip which you can get two of for free no problem. I am not sure any solution could be cheaper unless you want to make your own electrodes. In that case I have no suggestions.
Oh ok, I'll re-read your comment with that in mind.
http://developer.neurosky.com/docs/doku.php?id=arduino_tutorial
There seems to be this 'mindwave' device by Neurosky which appears to capture EEG activity cheaply (about £120). They even give a tutorial above of how to connect it to the arduino.
Does anyone know of the quality of data you can receive from this. It appears that it's supposed to be used to get how much the wearer is concentrating or something else along those lines. What I want to know is whether this limitation is due to the hardware or whether they just haven't gone for really algorithmic software to do something like I want to so I can determine whether it's worth a purchase.
The TI chip is the way to go. I have a sample, but haven't spent the time yet to solder it onto a board.
I've seen the EEG off of someone else's device though and the EEG was beautiful.
And, I would never hook an electrode to anyone without everything solely running on batteries, and no electrical connection to anything else.
I choose to protect me from myself. 
oscarcar:
And, I would never hook an electrode to anyone without everything solely running on batteries, and no electrical connection to anything else.
I choose to protect me from myself.
If you're not willing to power all your projects from your tesla coil, you are one very poor mad scientist, indeed.