# Power Calculations

Hi, I have a Power Meter (NorthQ Power Meter) that calculates my whole house energy consumption by counting the led pulses in my analog power meter.

However the return is just the number of pulses (Watts) so in order to get the consumption I need to calculate the pulses between a certain interval (say 1 minute). And then multiply by 60 to get the watt hour:

Time Watt Wh
10:00 123456789
10:01 123456799 (123456799-123456789)x60

The value of the Wh i want to store someware to show in a graph later on. So questions:

How do I set a variable every minute?
I guess I need to set two variables to be able to subtract them?
How do I store the third variable (Wh) so I keep the history?
And how do I mark it so Homey recognise it as power consumption.

Thanks!
Pär

Create VD and assign calculated value to it every minute. In my case I do calculate and assign negative power from one clamp to VD so the overall consumption is correct.

There was an app that had some math functions. Check better logic app. Idi not use it but maybe it can help you.

With Logic you can do Math. no app needed. 1 Like

Hi. Which app did you use to add NorthQ’s Power Meter into your Homey?

Regards Christer

Hi, I use abeggled/com.northq on GitHub.

br
Pär