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49 lines
2.1 KiB
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49 lines
2.1 KiB
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Non-Invasive Power Meter
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So an essential part of making your home smart is knowing how much power it uses over
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the day. Tracking this can be difficult, often you need to install a completely new
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power meter which can often cost a bunch of money. However, quite a few power meters
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have a red LED on the front that blinks every time that one Wh has been used.
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The simple idea therefore is: Why don't we just abuse that functionality to make the power-meter
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IoT enabled? We just have to hook up a simple photoresistor in front of that aforementioned
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LED and track the amount of pulses we receive. Then using esphomelib we can instantly have
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the power meter show up in Home Assistant 🎉
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.. note::
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This guide currently only works with the ESP32, and even if it is ported back to the ESP8266
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at some point, the ESP32 will still achieve a much higher accuracy because it has a
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hardware-based pulse counter.
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Hooking it all up is quite easy: Just buy a suitable photoresistor (make sure the wave length
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approximately matches the one from your power meter). Then connect it using a simple variable
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resistor divider (see `this article <https://blog.udemy.com/arduino-ldr/>`__ for inspiration).
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And... that should already be it :)
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.. figure:: images/power_meter-header.jpg
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:align: center
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:width: 80.0%
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For esphomelib, you can then use the
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:doc:`pulse counter sensor </esphomeyaml/components/sensor/pulse_counter>` using below configuration:
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.. code:: yaml
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sensor:
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- platform: pulse_counter
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pin: GPIO12
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unit_of_measurement: 'kW'
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name: 'Power Meter'
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filters:
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- multiply: 0.06
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Adjust ``GPIO12`` to match your set up of course. The output from the pulse counter sensor is in
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``pulses/min`` and we also know that 1000 pulses from the LED should equal 1kWh of power usage.
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Thus, rearranging the expression yields a proportional factor of ``0.06`` from ``pulses/min`` to
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``kW``.
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And if a technician shows up and he looks confused about what the heck you have done to your
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power meter, tell them about esphomelib 😉
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