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Author Topic: EEG-ANALOG-ASM problem  (Read 2112 times)

komanche

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EEG-ANALOG-ASM problem
« on: May 10, 2014, 12:57:22 AM »
Hello,
I bought the assembled analog board and connected it to my DIY ModEEG-like "digital" board (based on AtMega16, powered from 12V accu, with separated power source for section after transoptors but without the DCDC separator onboard - I think it is not required, when power sources are physically separated). I've connected the board just like in ModEEG - pin 1 to 5V (real ~4.8V) (after filtration like in original schematics), pin 2 to 2.0V (real 1.98V), 3-NC, 4-ADC0, 5-GND (main ground plane on digital board), etc.

The program sends readings 256 times per second, form ADC0 and ADC3 (all others are filled with zeroes), with protocol P2 (hex A5 5A 02 01 03 FF 03 FF 00 .... 00, 17 bytes, for first packet and "1023" reading on ADC0 and ADC3).

I placed the analog board in cube built with laminate for PCBs (wthout front and rear walls) and soldered  (of course, after removing amplifier chips from the board) short wires to 5 RCAs connectors (1  CH1+, 2 CH1-, 3 CH2+, 4 CH2-, 5 - DRL ; all shieldings connected to DRL too.).

When all of inputs was shorted to DRL signal looks like this:


(just after powering on)

I placed adhesive ECG electrodes on my chest and connected DRL to one, and CH1+ and CH1- shorted together to second. Signal after powering on:


When i left ch1+ and drl connected to two electrodes on my chest and put the ch1- on my tongue, nothing was happened:



Finally, I left the DRL placed on my chest and connected ch1 +/- via two silver electrodes to my head (O1-P3 fields). Signal looks like above or this (depends on the... nothing)


This board is precalibrated and nothing else is needed, isn't it?
« Last Edit: May 10, 2014, 01:03:10 AM by komanche »