Olimex Support Forum

Others => Biofeedback - EEG, ECG, EKG => Topic started by: marcpaul on November 14, 2013, 07:19:48 pm

Title: EKG-EMG analog channels
Post by: marcpaul on November 14, 2013, 07:19:48 pm
hey!

i recently got the stm32 + ekg-emg shield and it's working fine so far... :)

but i have some questions which are not that well documented i think...

when i connect 1 ekg-shield to the stm32 then i get a signal on 1 analog input is that right?

so the signals from the 3 connected electrodes are somehow merged into 1 signal?

for ekg (ecg) this is working fine... but if you want to to some emg or eog where more then 3 electrodes are involved this would be a problem... is there a chance to get the single signal for each electrode?

i hope someone can help me there... thanks a lot...

marc
Title: Re: EKG-EMG analog channels
Post by: LubOlimex on November 15, 2013, 12:03:53 pm
Hey marc,

Quoteis there a chance to get the single signal for each electrode?


No, unfortunately. As a starter one of the signals is GND so it is not usable for input by default. The other two are syn-phase signals and you would need to change the whole firmware to use them separately (and you would change the whole idea behind the usage of this type of shield).

You can use 3 shields mounted one over the other.

Best regards,
Lub/OLIMEX
Title: Re: EKG-EMG analog channels
Post by: marcpaul on November 15, 2013, 12:23:10 pm
ok thanks anyway... :)

i thought so but ... hey it was worth a try :D

but with my protoshields and a little soldering it should be possible to build a single channel...

anyway the ecg shield is nice... with a little tuning you get a perfect signal.. didn't except that good results...

big fan of the stuff you do...

marc