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[on:]

Hi guys

i want to use "Arduino mega 2560 " as data acquisition,
but the analog signal is bipolar(ECG signal)

so can i direct measure this signal or i need signal conditioning circuit?

[Reply #1 on:]

Hi guys

i want to use "Arduino mega 2560 " as data acquisition,
but the analog signal is bipolar(ECG signal)

so can i direct measure this signal or i need signal conditioning circuit?

You will need some form of external signal conditioning as the arduino analog inputs cannot safety handle negative voltages (below -0.5vdc) or positive voltages about Vcc + 0.5vdc. This same voltage limit applies to the digital input pins also.

Lefty

[Reply #2 on:]

thank you(retrolefty)

are there datasheet for analog input?

[Reply #3 on:]

thank you(retrolefty)

are there datasheet for analog input?

Well there is a Atmel datasheet avalible that covers the complete mega2560 chip that has sections covering the build in ADC.
http://www.atmel.com/images/doc2549.pdf
Lefty

[Reply #4 on:]

thanks

[Reply #5 on:]

May this post enabling differential input for Arduino handy.. http://arduino.cc/forum/index.php/topic,147830.msg1110852.html#msg1110852