Time, Sunrise and Sunset Routines: How to Schedule Home Automation That Follows the Day

This article is part of our wider coverage of home automation in Hyderabad. Every automation has a trigger, conditions and actions; sensor-triggered home automation covers triggers that come from motion and door sensors. This guide covers the other big family: triggers that come from the clock and the sun. Colour-temperature schedules for lighting are a separate topic, covered in how to plan circadian lighting schedules.

The three kinds of time trigger

Every scheduled routine starts from one of three triggers. Picking the wrong one is the root cause of most "the timer is annoying" complaints.

In practice most schedules combine two of these: a clock or sun trigger, and a calendar that says on which days it fires. "Sunset − 15 minutes, every day" and "06:00, weekdays only" are both complete schedules. What a schedule should almost never be is a clock time standing in for the sun.

How much the day moves in Hyderabad (with real numbers)

Hyderabad sits at about 17.4°N, so the swing in day length is smaller than in Delhi or Europe — but it is still far too large for a fixed timer. Approximate sunrise and sunset times in IST across the year:

Three things follow from these numbers:

• Sunset moves by about 75 minutes across the year, and sunrise by about 70. Any single fixed time is badly wrong for several months.
• Twilight is short. Civil twilight — the period after sunset when there is still useful light outdoors — lasts only about 22–24 minutes at Hyderabad's latitude. Indoors, especially in towers with deep balconies, rooms get dim well before sunset. That is why indoor evening routines usually need a negative offset.
• The weather moves it too. On a heavy monsoon afternoon in July or August, rooms can feel like dusk an hour early. A sun-based schedule cannot know about clouds; where this matters, a light-level condition or a one-touch Evening button on the keypad covers the gap. How to plan lighting and curtains around daylight covers light-level sensing in detail.

One thing Indian homes do not have to worry about is daylight saving time: IST does not change, so there is no spring-forward or fall-back hour to break schedules, as happens in many other countries.

Offsets and clamps: making sunset routines feel right

Offsets

An offset shifts a sun-based trigger earlier or later. The right offset depends on what the routine is for:

Clamps: "but not before, and not after"

An offset alone still follows the sun to extremes. A clamp puts limits on it: sunset − 20 minutes, but not before 5:30pm and not after 6:40pm. Clamps are the difference between a schedule that is technically correct and one that feels right. Two common uses:

• Morning routines: "sunrise + 30 min, not before 6:30am" keeps summer mornings from opening the curtains while the family is asleep.
• Evening routines around family time: "sunset − 20 min, not after 6:45pm" means the living room is ready when people are usually home, even in July.

If a system cannot express clamps directly, the same effect can be built from two schedules and a condition. The design intent is what matters: write down, for each routine, the trigger, the offset and the limits.

The location has to be right

Sun-based triggers are calculated from the home's latitude and longitude and its time zone. If the gateway is set to a default location or the wrong time zone, every sunrise and sunset routine is wrong by a fixed amount — sometimes by hours. Checking the configured location and the gateway's clock is part of commissioning, not something to assume.

A worked daily schedule for a Hyderabad home

This is a starting schedule for a 3BHK apartment with a west-facing living room and a balcony, or the equivalent zones in a villa. Each row is one routine with its trigger, the days it runs and the actions. It is deliberately short: schedules handle the predictable parts of the day, and keypads and sensors handle the rest.

Notice what is not scheduled: bedtime itself. Good Night is a button on the bedside keypad, because the family goes to bed at different times on different nights, and a house that switches itself off at 11pm while someone is still reading is a house people learn to fight. The 23:00 and 23:30 routines only change things nobody is actively using.

The loads in this schedule are the everyday ones: dimmable and tunable lighting, motorised curtains and door and motion sensors. For outdoor lighting specifically, how to plan balcony, façade and outdoor lighting covers which circuits should follow the sun.

Schedules and people: overrides, modes and exceptions

Rule 1: a schedule is an event, not a state

A scheduled routine should act once, at its time. If the Privacy routine closes the sheers at 6:23pm and someone opens them again at 6:30 to look at the rain, they should stay open. The next time the house touches them is the next scheduled event or the next button press. Systems that re-apply a state every few minutes ("the curtains should be closed after sunset") feel like they are overruling the family, and they are the fastest way to get automation switched off.

Rule 2: conditions for routines that could be unwelcome

Some routines should check before they act:

• Only if the home is not in away mode — a wake-up scene in an empty home is pointless; away mode runs its own presence routines instead. How to plan away mode when you travel covers that side.
• Only if the room has not been changed manually in the last 30–60 minutes — useful for the evening scene, so it does not undo a movie setting someone chose at 5:45.
• Only if a door contact reports closed — for example, not closing balcony-side curtains on an open sliding door.

Rule 3: modes switch whole groups of schedules

Rather than editing schedules when life changes, group them under modes. Normal runs everything. Holiday (everyone home, no school) skips the weekday wake-ups. Guest leaves the guest bedroom out of every schedule. Away suspends the family routines and runs presence simulation instead. One button or one tap changes the mode; nobody has to remember which timers to disable before Diwali week.

Rule 4: gentle transitions

A scheduled change nobody asked for should be noticeable but not startling. Lights fade over one or two minutes rather than snapping; curtains move at their normal speed rather than in a sudden full close while a guest sits beside the window. The 22:00 wind-down in the schedule above is a good example: it suggests bedtime without forcing it.

Where schedules run, and what happens after a power cut

Local, not cloud

Schedules should be stored on the home's own gateway and run there. If they depend on a cloud server, an internet outage means the evening lights and the privacy curtains simply do not happen, and a slow cloud means routines fire a few seconds or minutes late. In a Zigbee system like Pert's, the gateway sends the command straight to the keypads, light controllers and curtain motors over the local mesh; the internet is needed for remote access from your phone and for keeping the clock accurate, not for the routine itself. Do smart homes work during power cuts and internet outages? covers the wider picture.

Keeping time

A local scheduler is only as good as its clock. Gateways normally synchronise time over the internet and keep counting between syncs. After a long power cut together with an internet outage, the clock should be confirmed as correct once the connection returns — a gateway that comes back with the wrong time will run every routine at the wrong moment until it resyncs. This is one of the checks we include in a handover test: disconnect the internet, restart the gateway, and confirm the next routine still fires on time.

Missed events: do not replay the past

If power fails at 6:00pm and returns at 7:15pm, the sunset routines were missed. Should the system replay them? Usually not blindly. The safer behaviour is:

• Lights and curtains return to their configured power-on state (typically their last state), not to whatever a missed schedule would have set.
• Outdoor lights, which have a clear "should be on between sunset and sunrise" meaning, can reasonably be brought back on if power returns during that window.
• Nothing that moves or makes noise — curtains, a morning scene — should run on its own an hour late.

These choices are made per routine during design, because "catch up" is right for the gate light and wrong for the bedroom curtains.

Common scheduling mistakes

How Pert delivers it — a designed solution, not a DIY kit

Scheduling is where a designed system and a collection of app timers feel most different. On every project our team talks through the family's weekday and weekend routine, notes which windows face west and where daylight disappears first, and writes a short schedule like the one above with each routine's trigger, offset, clamp, days and conditions. We set the gateway's location and time correctly, build the modes (normal, holiday, guest, away), decide per routine what should happen after a power cut, and engrave the keypads so that the unscheduled moments — Good Night, Movie, Leaving — are one press away. Pert's keypads, lighting, curtains and security devices work together as one Zigbee system through the Pert gateway, and before handover we test the schedule with the internet disconnected. After handover, when school timings change or summer arrives, we adjust the schedule with you rather than leaving you to hunt through an app.

If you are still choosing who should design and install your system, best home automation companies in Hyderabad lists the questions to ask — including where their schedules and routines actually run.

Frequently asked questions

Should an evening lighting routine use a fixed time or the sunset time?

Use sunset with an offset for anything that depends on daylight: façade and balcony lights, evening scenes and closing sheers. In Hyderabad sunset moves from about 5:40pm in late November to about 6:55pm in early July, so a fixed 6:30pm timer is almost an hour late in winter and about 25 minutes early in midsummer. Use a fixed time for anything tied to the family's routine, such as a 6am weekday wake-up. Many routines work best as both: sunset minus 20 minutes, but not before 5:30pm and not after 6:45pm.

Do scheduled routines still run if the internet is down?

In a well-designed system, yes. Schedules should be stored and run on the local gateway, not in a cloud server, so an outage does not stop the evening lights or the privacy curtains. The internet provides time synchronisation and remote access from your phone. The gateway keeps its own clock between syncs, and a good handover test includes disconnecting the internet and confirming the next routine still runs on time.

Will a schedule undo something I just changed by hand?

It should not. A scheduled routine acts once, at its time, and then the house belongs to the people in it. If you open the curtains after the sunset routine closed them, they stay open until the next scheduled event. Where a routine could be unwelcome, it is given a condition — for example, only running if the room has not been changed manually in the last half hour, or not in guest mode.

How many scheduled routines does a typical home need?

Fewer than most people expect. A typical Hyderabad 3BHK is well served by six to twelve: weekday and weekend wake-ups, sunset routines for the façade and living room, a summer afternoon close on west-facing windows, a late-evening night path, a night security check and sunrise off for outdoor lights. Everything else belongs on a keypad button or a sensor. Each schedule should be written down with its trigger, days and exceptions so the family knows why the house does what it does.