Schedules GATT Characteristic

UUID: b77abf7f-66b5-4899-821d-efb177843783 Service: Shelly (de8a5aac-a99b-c315-0c80-60d4cbb51225)

All multi-byte values are little-endian. Temperature target is an IEEE 754 float (4 bytes LE). Max 10 rules (IDs 0-9). Timespec is a 6-field cron string: SEC MIN HOUR DOM MON DOW.

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Read

Returns all active rules packed sequentially, terminated by 0xFF:

 repeat per rule:
 ┌──────────┬──────────┬────────────────┬──────────┬──────────────────┐
 │ rule_id  │ enable   │ target         │ ts_len   │ timespec         │
 │ uint8    │ uint8    │ float (4B LE)  │ uint8    │ char[ts_len]     │
 └──────────┴──────────┴────────────────┴──────────┴──────────────────┘
 terminator:
 ┌──────┐
 │ 0xFF │
 └──────┘

Example

Device has two rules — rule 0 (enabled, 21.5 °C, weekdays 07:00) and rule 3 (disabled, 18.0 °C, daily 22:30):

00 01 00 00 ac 41 11 30 20 30 20 37 20 2a 20 2a 20 4d 4f 4e 2d 46 52 49
03 00 00 00 90 41 0d 30 20 33 30 20 32 32 20 2a 20 2a 20 2a
ff

Breakdown:

Bytes	Field	Value
00	rule_id	0
01	enable	1 (yes)
00 00 ac 41	target	21.5 °C
11	ts_len	17
30 20 … 49	timespec	0 0 7 * * MON-FRI
03	rule_id	3
00	enable	0 (no)
00 00 90 41	target	18.0 °C
0d	ts_len	13
30 20 … 2a	timespec	0 30 22 * * *
ff	terminator	—

Empty device returns a single byte: ff.

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Write

Add rule (0x01)

Assigns the first free rule ID automatically.

 ┌──────┬──────────┬────────────────┬──────────┬──────────────────┐
 │ 0x01 │ enable   │ target         │ ts_len   │ timespec         │
 │      │ uint8    │ float (4B LE)  │ uint8    │ char[ts_len]     │
 └──────┴──────────┴────────────────┴──────────┴──────────────────┘

Example — add enabled rule, 21.5 °C, weekdays at 07:00 (0 0 7 * * MON-FRI):

01 01 00 00 ac 41 11 30 20 30 20 37 20 2a 20 2a 20 4d 4f 4e 2d 46 52 49

Update rule (0x02)

Modifies an existing rule by ID.

 ┌──────┬──────────┬──────────┬────────────────┬──────────┬──────────────────┐
 │ 0x02 │ rule_id  │ enable   │ target         │ ts_len   │ timespec         │
 │      │ uint8    │ uint8    │ float (4B LE)  │ uint8    │ char[ts_len]     │
 └──────┴──────────┴──────────┴────────────────┴──────────┴──────────────────┘

Example — update rule 0, enabled, 18.0 °C, daily at 22:30 (0 30 22 * * *):

02 00 01 00 00 90 41 0d 30 20 33 30 20 32 32 20 2a 20 2a 20 2a

Remove rule (0x03)

 ┌──────┬──────────┐
 │ 0x03 │ rule_id  │
 │      │ uint8    │
 └──────┴──────────┘

Example — remove rule 2:

03 02

Remove all (0xFF)

 ┌──────┐
 │ 0xFF │
 └──────┘

Example:

ff

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Error responses

Write errors are returned as ATT status codes:

ATT status	Meaning
0x00	Success
0x0D	Invalid length (missing fields, ts_len mismatch)
0x11	Out of range (rule_id >= 10)
0x13	Value not allowed (rule_id does not exist)
0x11	Insufficient resources (no free slot on add)
0x06	Request not supported (unknown command byte)

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Reference float values

°C	Hex (LE)
5.0	00 00 a0 40
18.0	00 00 90 41
20.0	00 00 a0 41
21.0	00 00 a8 41
21.5	00 00 ac 41
22.0	00 00 b0 41
25.0	00 00 c8 41
30.0	00 00 f0 41

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GUI tool

python3 tools/schedules.py

Requires pip install bleak.