What do you need before you start?
- A Home Assistant install at your parent's home with working broadband, or one at yours that can reach their sensors. Sensors only help if the box that reads them stays online. See our UPS guide if power cuts are a worry.
- Two or three battery sensors: a motion sensor in the kitchen, one in the bedroom or landing, and a contact sensor on the front door. Our Zigbee motion sensor roundup and door sensor roundup cover options.
- The Companion app on your phone, so alerts reach you wherever you are. If you have not set it up, start with the notifications guide.
- Your parent's agreement. This is the step people skip, and it matters most.
Step 1: Agree what is monitored and who is told
Sit down with your parent before buying anything and explain exactly what the sensors record and who gets the alert. Say that there are no cameras and no microphones, that you will see only "activity or no activity", and that they can switch the whole thing off with a single helper toggle.
Agree a short list of people who will receive the alert, ideally two, so that a missed notification on one phone does not matter. Agree what happens when it fires: a phone call first, then a neighbour or a visit. Write the plan down and stick it on the fridge. An alert with no agreed response just creates worry, and a parent who feels watched will unplug the sensors.
Step 2: Place the sensors where routine is predictable
Pick spots your parent passes every day without thinking. The kitchen is the best single choice, because almost everyone makes a hot drink in the morning. A second motion sensor on the landing or in the bedroom confirms they have got up, and a contact sensor on the front door records going out and coming in.
Mount motion sensors at roughly shoulder height facing the doorway, away from radiators and windows that cause false triggers. Avoid the bathroom unless your parent specifically wants it; it adds little and feels intrusive. Pair each sensor and give it a plain name such as binary_sensor.mum_kitchen_motion, because you will type those names into the automations below.
Step 3: Record the last time anything moved
Create a helper that stores the most recent activity. In Settings > Devices & services > Helpers > Create helper > Date and/or time, make a helper named "Mum last activity" with both date and time enabled. Its entity ID will be input_datetime.mum_last_activity.
Then add one automation that stamps it every time a sensor reports activity. Using a helper rather than reading each sensor's last_changed matters: a sensor that drops to unavailable also changes state, which would look like activity and hide the very problem you are trying to catch.
alias: Mum - record activity
triggers:
- trigger: state
entity_id:
- binary_sensor.mum_kitchen_motion
- binary_sensor.mum_landing_motion
- binary_sensor.mum_front_door
to: "on"
actions:
- action: input_datetime.set_datetime
target:
entity_id: input_datetime.mum_last_activity
data:
timestamp: "{{ now().timestamp() }}"
The Home Assistant documentation notes that an input datetime with a time exposes a timestamp attribute, and that you can pass a timestamp straight into the set action. Because the value is stored in the helper, it also survives a restart.
Step 4: Alert you if there is no activity by mid-morning
This is the core automation. At 10:00 it checks whether anything has moved since 08:30 and, if not, sends you a message. The check runs at a fixed time instead of waiting on a countdown, which is deliberate.
alias: Mum - no morning activity
triggers:
- trigger: time
at: "10:00:00"
conditions:
- condition: state
entity_id: input_boolean.mum_monitoring_paused
state: "off"
- condition: template
value_template: >
{{ state_attr('input_datetime.mum_last_activity', 'timestamp')
< as_timestamp(today_at('08:30')) }}
actions:
- action: notify.mobile_app_your_phone
data:
title: "No activity at Mum's"
message: "Nothing has moved since before 08:30. Please call her."
data:
push:
sound:
name: default
critical: 1
volume: 1.0
Create the input_boolean.mum_monitoring_paused helper first; it lets your parent, or you, pause alerts during a holiday, a hospital stay or a visit to family. The critical block is the iPhone critical-notification syntax from the Companion documentation, which lets an alert sound even in Do Not Disturb. Remove it if you would rather not be woken, and check the Android equivalent in the same documentation.
Adjust 10:00 and 08:30 to the person. Someone who rises at 06:00 needs an earlier check; someone who sleeps until nine needs a later one. Run it for a week and see how close the real "last activity" comes to the cutoff before trusting it.
Step 5: Add a night-time front-door alert
A door opening at 03:00 is worth knowing about, because it can mean confusion, a fall on the way out or an unwelcome visitor. This automation fires only at night and only when monitoring is not paused.
alias: Mum - front door at night
triggers:
- trigger: state
entity_id: binary_sensor.mum_front_door
to: "on"
conditions:
- condition: time
after: "23:00:00"
before: "05:30:00"
- condition: state
entity_id: input_boolean.mum_monitoring_paused
state: "off"
actions:
- action: notify.mobile_app_your_phone
data:
title: "Front door opened at night"
message: "Mum's front door opened. Worth a quick call."
To catch a door left open rather than opened, add for: "00:10:00" to the trigger. Be aware that the Home Assistant state trigger documentation says the for timer resets if Home Assistant restarts or automations reload, so a long countdown is the wrong tool for the morning check in Step 4 and acceptable only for short ones like this.
Step 6: Get warned when a sensor goes quiet
Silence from a dead sensor looks exactly like a quiet house, and that false reassurance is the main risk of this whole setup. Add a health check for every sensor, so you hear about a flat battery or lost connection before it hides a real problem.
alias: Mum - sensor offline
triggers:
- trigger: state
entity_id:
- binary_sensor.mum_kitchen_motion
- binary_sensor.mum_landing_motion
- binary_sensor.mum_front_door
to: "unavailable"
for: "02:00:00"
actions:
- action: notify.mobile_app_your_phone
data:
title: "Sensor offline at Mum's"
message: "{{ trigger.to_state.name }} has been unavailable for two hours."
Add a numeric state trigger on each sensor's battery entity below about 15% as a second warning. Battery-powered Zigbee sensors usually report their level, and a swap on your next visit is far better than a surprise.
Step 7: Test every automation before you rely on it
Open Settings > Automations & scenes, choose each automation and run it manually to confirm the notification arrives and reads clearly. Then do a real test: set the cutoff in Step 4 to a few minutes ahead, walk away from the sensors, and wait for the alert. Finally, pull the battery from a sensor and confirm you are warned after two hours.
Ask your parent to try it too. Seeing the message arrive on your phone, and knowing that you see nothing else, is often what turns a sceptical "I don't need this" into a comfortable yes.
Why do I get false alarms, and how do I fix them?
The alert fires on days they sleep in. Move the check later, or add a second condition so it only fires if the door sensor has not moved either. A fixed 10:00 check will never suit everyone, and a week of data shows where the line should sit.
A pet or visitor keeps resetting the timer. Visitors are fine, since activity is activity. For pets, point the sensor away from floor level or choose a pet-immune model; the motion roundup above flags which sensors cope with cats.
The alert never arrives. Check that the Companion app can reach Home Assistant from outside the house and that notifications are allowed for it in your phone settings. Our notifications guide walks through the common causes.
Nothing happens after a restart. The helper keeps its value, so the morning check keeps working. Only for countdowns restart, which is why the key alert avoids one.
Where does this setup fall short?
Sensors tell you when a routine breaks, not why. They will not detect a fall in a room with no motion sensor, and they cannot call for help on their own. For that you want a pendant alarm or a fall-detection device.
The Local Government Association describes telecare as the use of sensors and alarms to signal when someone is in distress, and many councils run telecare services for older people. A Home Assistant build is a good complement when family live far away, but it is not a certified service and nobody is monitoring it around the clock except you.
What should you build next?
Once the basics are running, a power-cut alert tells you when their house has lost mains, which explains a silent sensor network. In winter, a frost alert and a water leak sensor add real protection for an empty or poorly heated home.
