Best ADC for EEG?

Other Hardware Sensors
1

Hi,

What would be the best Arduino circuit to get close to the ADC in ADS1299?

Are there any new tweaks since the post in 2008:
https://forum.arduino.cc/index.php?topic=6549.0

Many thanks! k

2

What would be the best Arduino circuit to get close to the ADC in ADS1299?

Using an ADS1299! You cannot get closer.

Are there any new tweaks since the post in 2008:
Faster Analog Read? - Frequently-Asked Questions - Arduino Forum

In that post the topic is ADC speed. The ADS1299 is slower than the Arduino internal ADC but more precise. What exactly do you want to achieve?

3

Thanks. I am trying to understand how to build an EEG.

AFAIK, the analogue pins on Arduino provide 10bit resolution, and I think I need 12bit or ideally higher. How can I do this?

Experiment with increasing the resolution for AnalogueRead [link]?
Or perhaps do the ADC with something else on the breadboard and feed the results to digital pins?

Sorry, if this is stupid. Thanks.

4

AFAIK, the analogue pins on Arduino provide 10bit resolution, and I think I need 12bit or ideally higher. How can I do this?

By connecting an external ADC.

The technique of oversampling is a trick to increase the resolution in some situations but it doesn't work for every signal. Just one example: if you want to measure a static DC signal with 12bit resolution the oversampling trick won't work. You'll get 10bit resolution because the oversampling trick depends on some signal noise so a changing signal is necessary to be able to calculate the moving average.
Also an increase of 2bits in resolution results in a decrease of the sampling frequency by a factor of 16. You'll end in a sampling frequency of about 200Hz at most using the integrated ADC and you won't be able to switch to another input as the analog switch will tamper you're readings.

Thanks. I am trying to understand how to build an EEG.

Please describe why you think you will need more than 10bits for an EEG. Using my limited knowledge about EEG I would expect that 8bit resolution is more than enough for that task. What do you need the additional resolution for?

5

hi pylon,

thanks for your reply and sorry for the delay: I got carried away with something else, so the DIY EEG now is on hold for a bit.

I was told that 10bits would be the minimum, but honestly my knowledge is limited, so I can't tell you why... much to learn still...

I'll try to get back on this asap, thanks for your help.

k