Intermittent trigger is not reflected in digital read widget
pluto
mars
Hi All,
I am having my experiment setup as: Two external buttons are connected to D13 GPIO and D18 GPIO respectively on Cyton.
My query is:
Within a single data stream, we are using the Digital Read widget to detect the button press. We are able to observe the button press on the GUI for the first couple of trials, but when the button is pressed under the same data stream for the 3rd or 4th time (not constant), neither the widget seems not to detect it, nor it is logged in the log files.
What can be the solution to this?
@wjcroft, @retiutut I will be grateful for you on this.
Thanks & Regards,
Pluto
Comments
Pluto, hi.
If you have wired up this button circuit on a breadboard, (such as the necessary pullup resistor to Vdd) -- realize that breadboard contacts and wires sometimes perform intermittently. Depending on how much oxidation is present on contact surfaces, pressure or tension involved on wires / contacts / connectors, etc. As you know breadboard wires and contacts typically use nickel plated metal instead of the preferred gold surfaces (as are present on the channel pins, or the touchproof adapter female header connectors.)
So I'd first suggest double checking the integrity of all your wires, connectors, interconnect scheme, etc. Possibly some of these could be soldered instead of using friction connections. (But do NOT solder anything to the Cyton board.)
It's also possible that Analog Read mode, may be less sensitive to small voltage differences than Digital Read mode. Since a GPIO digital mode pin on the microcontroller, must match exactly the 3.3V level to be considered true.
Regards, William
The circuitry for triggering has been verified and no fault has been found. But still, the issue persists w.r.t the trigger logging.
Regards,
Pluto.
Have you tried comparing your results using Analog Read mode, as I previously suggested?? The PIC32 microcontroller is not recognizing your true / false logic levels. Reading the pin in Analog mode will show you the actual voltage levels being detected. PIC32 analog mode is a 10 bit value, 0 to 1024, representing the voltage range between 0V and 3.3V.