WaterMote EE-SY310 Photo Device Operating Voltage

[Vince]

Felix,

     What operating voltage did you use for the EE-SY310 Photo Device with the Moteino
for your WaterMote project? I assume you used 3.3 VDC to make it compliant with the Moteino
input pin? But the spec for the EE-SY310 has a 4.5 VDC minimum operating requirement?
Will the EE-SY310 operate reliable at a lower input voltage or do I need to run it at 5 VDC and
add a voltage divider at the Moteino Input pin?

Thanks,

Vince

[Felix]

It runs at 5V from the wall wart.
I updated the post about this: http://lowpowerlab.com/blog/2013/02/02/meet-the-watermote-moteino-based-water-meter-reader-ee-sy310/

[Vince]

Using 5VDC does the output of the EE-SY310 exceed the interrupt pin input voltage requirement
of the Moteino 3.3 VDC limit?

Thanks,

Vince

[Felix]

No, they are still 5V tolerant.

[Vince]

Felix,

OK, I am little confused I thought the max input voltage to the input pins of a Atmega328 is
Vcc plus .5 volts. So with the Atmega328 on the Moteino operating at 3.3 VDC that would be
3.8 VDC. You say they are 5 volt tolerant but I could not find that in the spec? Please explain
what I am missing here!

Thanks,

Vince

[Felix]

I was saying, from experience the pins are 5V tolerant. If you are worried, just use a voltage divider to get the 3.3V, ie 10+4.7K.

[Vince]

Thanks for the replies. My reason for asking was to understand the limits a little better.

Vince