My situation was a little bit different. We have one litter tray in our house, and want to check/empty it after every visit to minimise odour.
The tray is conveniently in the same room as my Raspberry Pi, though. So I was able to build my own sensor, with a PIR attached to an Arduino, plug it in to the Pi, and check its state with a serial sensor.
Every second, the Arduino sends a number. 0 means the tray hasn’t been visited. Greater than 0 is the time in seconds since last visit. The sensor also has a button attached - after cleaning the tray you hit the button, and the sensor is reset back to an unvisited state. This makes it a lot easier to track visits.
I have three sensors: One is just the raw readings from the serial device. One parses that reading from seconds to a friendly string. And one uses that string and a custom icon for use in the frontend.
sensor:
- platform: serial
name: raw poopmon
serial_port: /dev/ttyS3
- platform: template
sensors:
poopmon_time:
friendly_name: "Time when litter tray was last used"
value_template: >-
{% set time = states.sensor.raw_poopmon.state | int %}
{% set minutes = ((time % 3600) / 60) | int %}
{% set hours = ((time % 86400) / 3600) | int %}
{%- if time < 60 -%}
less than a minute
{%- else -%}
{%- if hours > 0 -%}
{% if hours == 1 -%}
1 hour
{%- else -%}
{{ hours }} hours
{%- endif -%}
{%- endif -%}
{%- if minutes > 0 -%}
{%- if hours > 0 -%}
{{ ', ' }}
{%- endif -%}
{%- if minutes == 1 -%}
1 minute
{%- else -%}
{{ minutes }} minutes
{%- endif -%}
{%- endif -%}
{%- endif -%}
litter_tray:
friendly_name: "Eli's litter tray"
value_template: >-
{% if states.sensor.raw_poopmon.state|int == 0 %}
Clean
{% else %}
Last used {{ states.sensor.poopmon_time.state }} ago
{% endif %}
icon_template: >-
{% if states.sensor.raw_poopmon.state|int == 0 %}
mdi:cat
{% else %}
mdi:emoticon-poop
{% endif %}
Automations are done by just looking at the raw readings:
automation:
- id: 'cat poop notification'
alias: cat poop notification
trigger:
platform: numeric_state
entity_id: sensor.raw_poopmon
above: 0
action:
service: notify.html5_notifier
data_template:
title: "\uD83D\uDCA9 alert"
message: Litter box has been visited
- id: 'clean tray notification'
alias: clean tray notification
trigger:
platform: numeric_state
entity_id: sensor.raw_poopmon
below: 1
for:
minutes: 3
action:
service: notify.html5_notifier
data_template:
title: "\uD83D\uDE3B alert"
message: Litter box has been cleaned
I haven’t checked yet, but it should be fairly easy to count visits by just looking for raw_poopmon changing state from 0 to >0.