[TriEmbed] TriEmbed Digest, Vol 20, Issue 11

[Glen Smith]

I never liked the whole AC power factor thing and phase shifting of
inductive and capacitive loads, the whole thing irritated me. Give me
digital signals any day. But given the specifics (a water heater) of the
application in question - That ginormous resistive heating element is going
to dominate the load - I suppose there might be a VERY small power supply
if its a right fancy water heater with a micro controller, but water
heaters are generally pretty simple. On the other hand, when I replaced
mine over Thanksgiving, I did see that I had the option of getting one with
WiFi!

Good point if you wanted to use the same type of circuitry on the HVAC
system though.

Glen

On Wed, Jan 14, 2015 at 10:38 PM, Dwight Morgan <dwight.w.morgan at gmail.com>
wrote:

> I think some guy on YouTube tells how to compensate for it but I need to
> look again.
>
>
>
> *From:* TriEmbed [mailto:triembed-bounces at triembed.org] *On Behalf Of *Mark
> Sidell
> *Sent:* Wednesday, January 14, 2015 10:35 PM
> *To:* Triangle Embedded Devices
> *Subject:* Re: [TriEmbed] TriEmbed Digest, Vol 20, Issue 11
>
>
>
> If I'm not mistaken, the Arduino circuit described measures apparent
> power, not true power, because it simply averages the current and doesn't
> take into account the voltage to current phase shift caused by inductive
> loads. Good enough to tell if your water heater is on, but it may not match
> what your electric meter says.
>
>
>
> On Wed, Jan 14, 2015 at 9:49 PM, Martin Brooke <martin.brooke at duke.edu>
> wrote:
>
> I used an audio jack breakout on an arduino proto shield with a simple RC
> circuit to level shift the AC.
>
>
>
> here is a photo
> <https://drive.google.com/file/d/0B0lP-6BNGel_a09EbFBkeDJWamc/view?usp=sharing>.
> The proto shield is this one from  sain smart
> <http://smile.amazon.com/SainSmart-Prototyping-Prototype-Breadboard-Arduino/dp/B0079WI2MK/ref=sr_1_4?ie=UTF8&qid=1421289842&sr=8-4&keywords=Prototype+Shield> although
> there are many alternatives for this.
>
>
>
> The break out was from sparkfun <https://www.sparkfun.com/products/10588>
> for which you need some headers <https://www.sparkfun.com/products/116>and
> the jack <https://www.sparkfun.com/products/8032>  maybe you can find one
> assembled
>
>
>
> There is also two resistors and a capacitor needed to get the AC signal
> into the ADCs input range.
>
>
>
> I really just copied the circuit from this intructable
> <http://www.instructables.com/id/Yun-based-Electricity-Monitor-with-Cloud-Support-T/?ALLSTEPS>
> .
>
>
>
> The instructable goes way further, using an Arduino Yun to make it
> readable via wifi, very cool, but maybe beyond what you want or need.
>
>
>
> Cheers,
>
>
>
> ​​
>
>
>
>
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