gistfile1.txt

<img src="/uploads/57c420cd4d04abe84cd93e14/image/wmeter.png" class="ir" style="max-width:25%">
<img src="/uploads/57c420cd4d04abe84cd93e14/image/track.png" class="ir" style="max-width:25%">

In some cases, newer water meters are equipped with a pulse output. However if you have an older power meter without a pulse output, then you might be able to use one of the options below to sense your water consumption.

Use the **TCRT5000 IR Barrier Line Track sensor**. It emits an infrared light and detects the reflection. If you aim it at the fastest turning hand on your meter, you can detect pulses or a rate.

Some water meters emit a fluctuating magnetic field that can be detected by using a **Hall effect** sensor. Instructions are available here.

The sensor example sketch counts the pulses from your attached sensor and converts it into liters or gallons per minute and the cummulative water volume.

There are a few parameters that need to be tuned to your water meter. Set the **PULSE_FACTOR** to the number of revolutions per cubic-meters (or gallons) of water.

You can also set the frequency that the sensor will report the water consumption by updating the **SEND_FREQUENCY**. The default frequency 3 times per minute (every 20 seconds). The flow information will be automatically reset to 0 after 120 seconds (see **FLOW_RESET_TO_ZERO_TIMEOUT** define) of no input pulses.

The sensor has two modes of operation:

**SLEEP_MODE = true**

Use this mode if you power the sensor with a battery. In this mode the sensor will sleep most of the time and only report the cumulative water volume. Unfortunately the sensor cannot report the current water flow rate because the sensor can not track time while sleeping; the elapsed time between two blinks is required to calculate the current flow rate.

**SLEEP_MODE = false**

In this mode the sensor will not sleep and will report the current water flow rate and the cumulative water consumption to the gateway. This mode requires constant power so you will need to connect the sensor to an electrical outlet.

## Usage with Home Assistant Controller
The sensor automatically register itself to home assistant controller which will release a NODE_ID to this sensor (through the gateway). If everything is fine, the NODE_ID will be set in the sensor EEPROM, and the board will get an initial counter value of 0 from Home Assistant. At this point, the sensor and Home Assistant are paired. The initial provisioning writes a flag in the sensor EEPROM indicating that the counter has been correctly provisioned to the sensor by Home Assistant, so that the board will start to use the counter incrementing on received pulses just after this event. The effect of this procedure is also that if you provision another sensor setting the same NODE_ID, you will get the current counter value from Home Assistant on the first startup.

***Factory Reset***

Just in case you want to register the sensor using another NODE_ID, you will need to factory reset this sensor. For user convenience, in the source code you will find a **FORCE_FACTORY_RESET** define that will allow you (uncommenting the line) to factory reset the board on startup (resetting NODE_ID and also the pulse counter provisioning flag). Once you started the board with this definition, you will see in the serial log that the board has been reset, so you can comment again this line in order to proper run the board as usual. Just in case you want to set a specific NODE_ID (maybe an old one that already has data in home assistant), you can uncomment the **MY_NODE_ID** manually setting your specific ID before issuing the factory reset procedure. After that you can comment back again this line.

***Setting a specific Volume counter value***

Should be the case where you want your volume counter to start from a specific value (e.g. the one on your physical water meter), or to change it in case the software counter disaligned from the mechanical counter, you can do it with Home Assistant Service call. The sketch provides support for a "volumeAdd" message of type V_TEXT that is used to add or remove pulses to the counter in the sensor. In order to do that you will go to Home Assistant service call helper (in the developer tools), go in yaml mode and use these:
```
service: notify.mysensors
    data:
        message: **VALUE_TO_ADD**
        target: Water Meter **NODE_ID** 2
```
you will need to set:

**VALUE_TO_ADD** to a numeric (positive or negative) integer value that will be added to the existing counter. Mind that currently this may go in overflow if you use too big values. The number is expressed as "pulses" units, so if you want to add 1.234 m3 to the current value of volume (e.g. 1000 m3) you will set here 1234 and just after some seconds you will find 2.234 m3 in the volume shown by Home Assistant.

**NODE_ID** to the one assigned to your sensor. 2 is the child entity and will correspond to the text of S_INFO entity attached to this device (you see this in the entities)

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## Wiring Things Up

Start by [connecting the radio module](/build/connect_radio).

<img src="/uploads/57c420cd4d04abe84cd93e14/image/doao.png" class="ir" style="max-width:30%">
<img src="/uploads/57c420cd4d04abe84cd93e14/image/APM_D3.png" class="ir" style="max-width:30%">

| Sensor             | Arduino            | Comment           |
|--------------------|--------------------|-------------------|
| GND                | GND                | Black             |
| VCC                | VCC (3.3 - 5V)     | Red               |
| DO (digital out)   | Digital pin 3 (D3) | Green             |