Analog or digital ground? The two are different.
The digital ground will appear to float since the two are not connected.
AGND is at P9-34, whereas GND is P9-1, P9-2, P9-43->46 and P8-1, P8-2.
Chad
On 12/18/2014 11:44 AM, mab.mobile...@gmail.com wrote:
Hello,
I am trying use the Beaglebone Black to monitor a smoke detector
activation. I have two wires coming from the smoke detector, ground
and positive lead. The voltage on the wires will go to 0.6v when the
detector is activated. I have the ground connected to the P9 header
GNDA_ADC and the positive wire from the detector going to AIN6. When
monitoring the base values of AIN6 without the detector being
activated I get a wide range of values. Example output below...
pin AIN6 value is 2
pin AIN6 value is 105
pin AIN6 value is 0
pin AIN6 value is 0
pin AIN6 value is 687
pin AIN6 value is 195
pin AIN6 value is 29
pin AIN6 value is 1799
pin AIN6 value is 182
pin AIN6 value is 0
When the detector is activated the AIN6 value will just be above 1000.
However the random base values frequently exceed 1000 as well
resulting in a lot of false positive activations.
My questions..
1. Why is there so much variance in the base AIN values when no
voltage is being applied? Should it not be near or at zero?
2. What can I do to remedy this so I can get consistently low baseline
AIN values so I do not generate false positive activations?
Please remember - newbie question with very basic knowledge of
electronics.
Thanks
--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google
Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send
an email to beagleboard+unsubscr...@googlegroups.com
<mailto:beagleboard+unsubscr...@googlegroups.com>.
For more options, visit https://groups.google.com/d/optout.
--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to beagleboard+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
