Basic RC Circuit to get the basic setup of the XOscillo program

[jeremy]

(1) (2)
O-------/\/\/\/\----O ----|(------O (GND)
|
Pin=?
O = node
-/\/\/\- resistor
-|(- capacitor

I'm not sure what pins to connect to which node right before the
capacitor.
Also the pin(s) for the node before the resistor.

I currently have node (1) in analog pin 0 to read the input signal and
node (2) in analog pin 1.
After running XOscillo.exe and opening analog arduino it fails to open
COM3 (serial port my arduino is connecting to the computer) and it
also keeps saying "Waiting for trigger..."

I don't know much about how an actual oscilloscope would be wired to
this circuit. I did this in LabVIEW for class, but want to know more
about the arduino abilities.

Thanks,
Jeremy

[Raul Aguaviva]

Hi,

You just have to connect the arduino's ground to your circuit's ground
and then analog0 to (2)

That should work, let me know how it works
Raul

[jeremy]

I have analog0 at (2). I have node (1) going to the 3V3 pin. Is that
correct? Trigger = 0 and just 1 channel.

The XOscillo program now brings up a grid with the fps and a red line.
Seems to be working.
My time constant is around 0.112sec (8.9Hz) for the RC circuit and I
only see a straight line from (0m, 172.13) to (85m,172.13). I can't
get a good view on the charging/discharging of the capacitor. Is there
a setting in the XOscillo program i can change to get that curve?
Increase the samples (1024 currently) ?

Thanks

[Raul Aguaviva]

Hi Jeremy,

The discharge is probably happening but you dont see because it happens very quickly... try using a higher resistor.

If you still want to use your current resistor you'd need to apply a square wave to your filter, that way you get the cap to charge and discharge many times per second.

Raul

[jeremy]

Thanks Raul. What do I have to do to get a square wave input or even a
sine wave input through XOscillo?

Jeremy