EKG-EMG analog channels

Started by marcpaul, November 14, 2013, 07:19:48 pm

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marcpaul

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

LubOlimex

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
Technical support and documentation manager at Olimex

marcpaul

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