This is a component that allows you to control your SEC-TOUCH ventilation controller (Dezentrale Lüftung Zentralregler SEC-Touch) from your ESP device and integrate it to Home Assistant.
It allows you to change the level of the fan pairs, put them into their special modes (automatic, time, etc), and toggle global settings such as Summer Ventilation. There is no way to change the timing intervals for now. You need to make that in the SEC-TOUCH device itself.
The SEC-Touch device is always the source of true. No fan state restoration is done after a power loss.
- Manuel Siekmann who did the heavy lifting of find out the communication protocol of the SEC-TOUCH device in his VentilationSystem project.
- Samuel Sieb who helped me to understand some basic c++ and ESPHome concepts and responded my questions on Discord.
The SEC-Touch has no open API or documentation for their UART interfaces, so I can no and DO NOT offer any warranty, everything here is reverse engineered. I have no affiliation with the company that produces the SEC-TOUCH device nor do I want this component to be used for financial gains. The only reason I developed this is because the official alternative is needs internet to works, which I do not want for a device that costs +200€ EURO.
If you decide to use this component a fan damage can not be ruled out. You are the only responsible in case something goes wrong.
Yes Really.
- An ESP32 or ESP8266 device.
- I use this one with USB C.
- 4 Pin Pluggable Terminals
- 4 core or 3 core cable (depending on how you can/want to power the ESP device)
- Breakout board if you do not want to solder stuff
- PCB board with header connectors if you want to solder everything (like I did, see bellow).
- Din Rail Mounting clips to mount the device if needed.
The SEC-TOUCH has an "PC" port at the right bottom part. It has an 3.x volts output. It worked to power my ESP32 device when I was using Software UART, but when I switched to Hardware UART it didn't work anymore. When I measured the voltage it was around 3.2v tops.
I recommend you to power your ESP32 device using another source.
That said, probably it has enough power for an ESP8266 device that uses software UART.
The same but without the 3.3v connection. 😬
| ESP32 | SEC-Touch |
|---|---|
| GND | GND (1st from the left) |
| GPIO 17 | RX (2nd from the left) |
| GPIO 16 | TX (3rd from the left) |
Add this to your-device.yaml file:
external_components:
- source:
type: git
url: https://github.com/distante/esphome-components
ref: stable
wifi:
ssid: !secret wifi_ssid
password: !secret wifi_password
# Enable fallback hotspot (captive portal) in case wifi connection fails
ap:
ssid: "Ventilation-Controller"
password: "supersecretpassword"
captive_portal:
web_server:
port: 80
local: true
log: false
version: 3
sorting_groups:
- id: group_1
name: Fan Group 1
sorting_weight: -100
- id: group_2
name: Fan Group 2
sorting_weight: -99
- id: group_3
name: Fan Group 3
sorting_weight: -98
- id: group_4
name: Fan Group 4
sorting_weight: -97
- id: group_5
name: Fan Group 5
sorting_weight: -96
- id: group_6
name: Fan Group 6
sorting_weight: -95
- id: group_settings
name: Configuration
sorting_weight: -94
uart:
id: sec_touch_uart
tx_pin:
number: GPIO17
rx_pin:
number: GPIO16
baud_rate: 28800
sec_touch:
uart_id: sec_touch_uart
update_interval: 5s # 5s is the default
global_settings_update_interval: 30s # 30s is the default — controls how often global settings (e.g. summer ventilation) are re-polled
optional_crc: false # false is the default — set to true if your device sends responses without a CRC field
fan:
- platform: sec_touch
icon: "mdi:fan"
fan_number: 1
name: "Fan 1"
web_server:
sorting_group_id: group_1
- platform: sec_touch
icon: "mdi:fan"
fan_number: 2
name: "Fan 2"
web_server:
sorting_group_id: group_2
- platform: sec_touch
icon: "mdi:fan"
fan_number: 3
name: "Fan 3"
web_server:
sorting_group_id: group_3
- platform: sec_touch
icon: "mdi:fan"
fan_number: 4
name: "Fan 4"
web_server:
sorting_group_id: group_4
- platform: sec_touch
icon: "mdi:fan"
fan_number: 5
name: "Fan 5"
web_server:
sorting_group_id: group_5
- platform: sec_touch
icon: "mdi:fan"
fan_number: 6
name: "Fan 6"
web_server:
sorting_group_id: group_6
switch:
- platform: sec_touch
name: "Summer Ventilation"
icon: "mdi:weather-sunny"
web_server:
sorting_group_id: group_settings
button:
- platform: sec_touch
program_text_update:
name: "Program Labels Update"
icon: "mdi:book-refresh"
- platform: restart
name: "Restart"
text_sensor:
- platform: sec_touch
fan_number: 1
label_text:
name: "Label Fan 1"
web_server:
sorting_group_id: group_1
mode_text:
name: "Mode Fan 1"
web_server:
sorting_group_id: group_1
- platform: sec_touch
fan_number: 2
label_text:
name: "Label Fan 2"
web_server:
sorting_group_id: group_2
mode_text:
name: "Mode Fan 2"
web_server:
sorting_group_id: group_2
- platform: sec_touch
fan_number: 3
label_text:
name: "Label Fan 3"
web_server:
sorting_group_id: group_3
mode_text:
name: "Mode Fan 3"
web_server:
sorting_group_id: group_3
- platform: sec_touch
fan_number: 4
label_text:
name: "Label Fan 4"
web_server:
sorting_group_id: group_4
mode_text:
name: "Mode Fan 4"
web_server:
sorting_group_id: group_4
- platform: sec_touch
fan_number: 5
label_text:
name: "Label Fan 5"
web_server:
sorting_group_id: group_5
mode_text:
name: "Mode Fan 5"
web_server:
sorting_group_id: group_5
- platform: sec_touch
fan_number: 6
label_text:
name: "Label Fan 6"
web_server:
sorting_group_id: group_6
mode_text:
name: "Mode Fan 6"
web_server:
sorting_group_id: group_6
Notice that the fans numbers are ordered so:
| -- | -- | -- | -- |
|---|---|---|---|
| Pair 1 | Pair 3 | Pair 5 | ℹ️ |
| Pair 2 | Pair 4 | Pair 6 | ⚙️ |
Each component uses a distinct log tag. You can suppress noisy tags without hiding everything by adding a logger block to your YAML:
logger:
logs:
sec_touch: WARN # core component (polling loop, task queue, watchdog)
sec_touch.uart: WARN # raw UART sends/receives — very noisy at DEBUG
sec_touch.incoming: WARN # incoming message buffer (overflow warnings)
sec_touch.fan: WARN # fan entity state changes and control calls
sec_touch.mode_select: WARN # mode select entity
sec_touch.switch: WARN # summer ventilation switch
sec_touch_sniffer: DEBUG # sniffer discoveries and scan progress| Tag | Component | Noisy at DEBUG? |
|---|---|---|
sec_touch |
Core component — loop, task queue, watchdog | Yes |
sec_touch.uart |
Raw UART sends/receives | Very |
sec_touch.incoming |
Incoming message buffer | Low |
sec_touch.fan |
Fan entity | Moderate |
sec_touch.mode_select |
Mode select entity | Low |
sec_touch.switch |
Summer ventilation and other global switches | Low |
sec_touch_sniffer |
Sniffer (passive + active scan) | Moderate |
Tip: When using the sniffer and you only want to see discovery output, set
sec_touchandsec_touch.uarttoWARNandsec_touch_sniffertoINFOorDEBUG.
The sniffer listens for UART messages sent by the SEC-Touch for property IDs that no component has registered interest in. This lets you discover unknown property IDs for future use.
Two modes are available:
- Passive (always on): unknown IDs that arrive during normal polling are captured automatically.
- Active scan (optional): iterates through a configured range of property IDs, querying each one in turn. Normal polling is paused while scanning.
Results are published as a text sensor and visible in Home Assistant. An optional switch reflects whether a scan is currently running and can be toggled from Home Assistant.
Note: Active scan is not recommended on ESP8266. Each discovered entry uses ~80–100 bytes of heap; a 200-ID scan uses ~20 KB against only ~40 KB of usable heap.
text_sensor:
- platform: sec_touch_sniffer
sec_touch_id: sec_touch_component
name: "Sniffer"time:
- platform: homeassistant
id: ha_time
text_sensor:
- platform: sec_touch_sniffer
sec_touch_id: sec_touch_component
name: "Sniffer"
time_id: ha_time # optional — uses device uptime when omitted
scan_start: 1 # first property ID to query in active scan
scan_end: 250 # last property ID to query; must be >= scan_start
scan_switch:
name: "Sniffer Scan Active"Turning the switch on starts a scan from scan_start. Turning it off stops the scan immediately, publishes the results discovered so far, and saves the current position. Turning it on again resumes from where it left off. When the full range has been scanned, polling resumes automatically, the full result is published to the text sensor, and the switch turns off.
If a property ID does not respond within 2 seconds the scan retries it once. If it times out again the ID is skipped and a warning is logged.
Scan performed over IDs 1–208. IDs 78–83 (fan labels) and 173–178 (fan levels) are registered listeners and are excluded from the sniffer output — their meaning is already documented above.
If you recognize a pattern or know what an ID controls, please open a PR or issue.
Raw sniffer output (copy-paste ready)
1=23, 2=16, 3=0, 4=0, 5=100, 6=1, 7=1, 8=1, 9=0, 10=0, 11=0, 12=0, 13=0, 14=0, 15=0, 16=0, 17=0, 18=0, 19=80, 20=6, 21=16, 22=40, 23=32, 24=28, 25=25, 26=21, 27=0, 28=61, 29=70, 30=74, 31=77, 32=81, 33=100, 34=50, 35=50, 36=50, 37=50, 38=50, 39=50, 40=50, 41=50, 42=50, 43=50, 44=50, 45=50, 46=50, 47=75, 48=800, 49=1200, 50=400, 51=20, 52=70, 53=10, 54=20, 55=0, 56=127, 57=0, 58=1, 59=95, 60=1, 61=1, 62=1, 63=1, 64=1, 65=0, 66=1, 67=2, 68=3, 69=4, 70=5, 71=6, 72=0, 73=1, 74=1, 75=1, 76=1, 77=1, 83=0, 84=13, 85=0, 86=1, 87=0, 88=0, 89=0, 90=0, 91=0, 92=100, 93=74, 94=6, 95=0, 96=100, 97=250, 98=2000, 99=-50, 100=50, 101=18, 102=6, 103=11, 104=22, 105=9, 106=22, 107=0, 108=7, 109=4, 110=3, 111=0, 112=18, 113=13, 114=14, 115=7, 116=23, 117=7, 118=7, 119=0, 120=7, 121=2, 122=0, 123=0, 124=13, 125=14, 126=22, 127=4, 128=12, 129=7, 130=0, 131=1, 132=0, 133=0, 134=0, 135=13, 136=14, 137=20, 138=8, 139=12, 140=7, 141=0, 142=2, 143=0, 144=0, 145=0, 146=0, 147=23, 148=8, 149=15, 150=4, 151=7, 152=1, 153=1, 154=0, 155=7, 156=0, 157=6, 158=9, 159=15, 160=20, 161=22, 162=0, 163=0, 164=0, 165=0, 166=0, 167=0, 168=3, 169=0, 170=0, 171=0, 172=0, 176=0, 178=255, 179=127, 180=127, 181=127, 182=127, 183=127, 184=127, 185=36, 186=31, 187=27, 188=18, 189=10, 190=0, 191=64, 192=70, 194=85, 195=100, 196=0, 197=36, 198=31, 199=27, 200=23, 201=18, 202=10, 203=64, 204=70, 205=74, 206=80, 207=85, 208=100
ID analysis table (help wanted — fill in what you know)
IDs not in output: 48 (summer ventilation, registered listener), 78–82 (fan pair labels, registered listener), 173–175, 177 (fan pair levels, registered listener), 193 (no response from device).
| ID | Value | Hypothesis | Confidence |
|---|---|---|---|
| 1 | 23 | ||
| 2 | 16 | ||
| 3 | 0 | ||
| 4 | 0 | ||
| 5 | 100 | ||
| 6 | 1 | ||
| 7 | 1 | ||
| 8 | 1 | ||
| 9 | 0 | ||
| 10 | 0 | ||
| 11 | 0 | ||
| 12 | 0 | ||
| 13 | 0 | ||
| 14 | 0 | ||
| 15 | 0 | ||
| 16 | 0 | ||
| 17 | 0 | ||
| 18 | 0 | ||
| 19 | 80 | ||
| 20 | 6 | ||
| 21 | 16 | ||
| 22 | 40 | ||
| 23 | 32 | ||
| 24 | 28 | ||
| 25 | 25 | ||
| 26 | 21 | ||
| 27 | 0 | ||
| 28 | 61 | ||
| 29 | 70 | ||
| 30 | 74 | ||
| 31 | 77 | ||
| 32 | 81 | ||
| 33 | 100 | ||
| 34 | 50 | ||
| 35 | 50 | ||
| 36 | 50 | ||
| 37 | 50 | ||
| 38 | 50 | ||
| 39 | 50 | ||
| 40 | 50 | ||
| 41 | 50 | ||
| 42 | 50 | ||
| 43 | 50 | ||
| 44 | 50 | ||
| 45 | 50 | ||
| 46 | 50 | ||
| 47 | 75 | ||
| 49 | 1200 | ||
| 50 | 400 | ||
| 51 | 20 | ||
| 52 | 70 | ||
| 53 | 10 | ||
| 54 | 20 | ||
| 55 | 0 | ||
| 56 | 127 | ||
| 57 | 0 | ||
| 58 | 1 | ||
| 59 | 95 | ||
| 60 | 1 | ||
| 61 | 1 | ||
| 62 | 1 | ||
| 63 | 1 | ||
| 64 | 1 | ||
| 65 | 0 | ||
| 66 | 1 | ||
| 67 | 2 | ||
| 68 | 3 | ||
| 69 | 4 | ||
| 70 | 5 | ||
| 71 | 6 | ||
| 72 | 0 | ||
| 73 | 1 | ||
| 74 | 1 | ||
| 75 | 1 | ||
| 76 | 1 | ||
| 77 | 1 | ||
| 83 | 0 | ||
| 84 | 13 | ||
| 85 | 0 | ||
| 86 | 1 | ||
| 87 | 0 | ||
| 88 | 0 | ||
| 89 | 0 | ||
| 90 | 0 | ||
| 91 | 0 | ||
| 92 | 100 | ||
| 93 | 74 | ||
| 94 | 6 | ||
| 95 | 0 | ||
| 96 | 100 | ||
| 97 | 250 | ||
| 98 | 2000 | ||
| 99 | -50 | ||
| 100 | 50 | ||
| 101 | 18 | ||
| 102 | 6 | ||
| 103 | 11 | ||
| 104 | 22 | ||
| 105 | 9 | ||
| 106 | 22 | ||
| 107 | 0 | ||
| 108 | 7 | ||
| 109 | 4 | ||
| 110 | 3 | ||
| 111 | 0 | ||
| 112 | 18 | ||
| 113 | 13 | ||
| 114 | 14 | ||
| 115 | 7 | ||
| 116 | 23 | ||
| 117 | 7 | ||
| 118 | 7 | ||
| 119 | 0 | ||
| 120 | 7 | ||
| 121 | 2 | ||
| 122 | 0 | ||
| 123 | 0 | ||
| 124 | 13 | ||
| 125 | 14 | ||
| 126 | 22 | ||
| 127 | 4 | ||
| 128 | 12 | ||
| 129 | 7 | ||
| 130 | 0 | ||
| 131 | 1 | ||
| 132 | 0 | ||
| 133 | 0 | ||
| 134 | 0 | ||
| 135 | 13 | ||
| 136 | 14 | ||
| 137 | 20 | ||
| 138 | 8 | ||
| 139 | 12 | ||
| 140 | 7 | ||
| 141 | 0 | ||
| 142 | 2 | ||
| 143 | 0 | ||
| 144 | 0 | ||
| 145 | 0 | ||
| 146 | 0 | ||
| 147 | 23 | ||
| 148 | 8 | ||
| 149 | 15 | ||
| 150 | 4 | ||
| 151 | 7 | ||
| 152 | 1 | ||
| 153 | 1 | ||
| 154 | 0 | ||
| 155 | 7 | ||
| 156 | 0 | ||
| 157 | 6 | ||
| 158 | 9 | ||
| 159 | 15 | ||
| 160 | 20 | ||
| 161 | 22 | ||
| 162 | 0 | ||
| 163 | 0 | ||
| 164 | 0 | ||
| 165 | 0 | ||
| 166 | 0 | ||
| 167 | 0 | ||
| 168 | 3 | ||
| 169 | 0 | ||
| 170 | 0 | ||
| 171 | 0 | ||
| 172 | 0 | ||
| 176 | 0 | ||
| 178 | 255 | ||
| 179 | 127 | ||
| 180 | 127 | ||
| 181 | 127 | ||
| 182 | 127 | ||
| 183 | 127 | ||
| 184 | 127 | ||
| 185 | 36 | ||
| 186 | 31 | ||
| 187 | 27 | ||
| 188 | 18 | ||
| 189 | 10 | ||
| 190 | 0 | ||
| 191 | 64 | ||
| 192 | 70 | ||
| 194 | 85 | ||
| 195 | 100 | ||
| 196 | 0 | ||
| 197 | 36 | ||
| 198 | 31 | ||
| 199 | 27 | ||
| 200 | 23 | ||
| 201 | 18 | ||
| 202 | 10 | ||
| 203 | 64 | ||
| 204 | 70 | ||
| 205 | 74 | ||
| 206 | 80 | ||
| 207 | 85 | ||
| 208 | 100 |
Please check the Special Fan level Values section to understand the special values for the fan level.
By default each fan entity exposes all 11 levels as a single continuous speed range. Because levels 1–6 are continuous ventilation but levels 7–11 are discrete operating modes (Burst / Auto Humidity / Auto CO2 / Auto Time / Sleep), the default HA slider shows a linear 0–100 % range with 9.09 % steps — awkward to use and not visually distinguishable.
Enable split_special_modes: true on the fan to get a cleaner UX:
fan:
- platform: sec_touch
fan_number: 1
name: "Lüftung Büro"
split_special_modes: trueWith the flag enabled:
- The HA fan slider exposes only speeds 1–6 (
speed_count: 6), so each detent maps to one real ventilation level. - Levels 7–11 remain reachable through the existing preset_mode dropdown (
Burst,Automatic Humidity,Automatic CO2,Automatic Time,Sleep). - The flag is opt-in and defaults to
false— existing installations are unaffected. - HA reports percentages as truncated integers (
floor(level / speed_count * 100)), giving: 16, 33, 50, 66, 83, 100 for levels 1–6. Without the flag the values are 9, 18, 27, 36, 45, 54 (11-level range).
ℹ️ The preset dropdown is what HA already shows under the fan tile's "more info" view, or via the
fan-preset-modestile feature. It reads and writes the same underlying BDE level —split_special_modesjust keeps the slider range sane.
⚠️ ESPHome's built-inweb_serverdoes not render fanpreset_modedropdowns. If you rely on the local web UI (e.g. non-HA fallback), add aselect.sec_touchentity per fan to expose a clickable Mode dropdown. Seeexamples/webserver-fallback.yaml.
By default, every response from the SEC-Touch is expected to contain four TAB-delimited fields: command_id, property_id, value, and crc. If the CRC field is absent the component logs an error and discards the message.
Some firmware versions or configurations of the SEC-Touch appear to omit the CRC field, sending only [STX]command_id[TAB]property_id[TAB]value[ETX]. If you see repeated Not enough TABs in message … missing: [value, crc] errors in your logs but the parsed command_id and property_id look correct, enable this flag:
sec_touch:
uart_id: sec_touch_uart
optional_crc: trueWhen enabled, a message with a missing CRC field is still processed normally. A [D] debug log is emitted so you can confirm the behavior. Messages that are missing command_id or property_id are still rejected as malformed regardless of this setting.
For Home Assistant integration details, custom card examples, and tips for the best HA experience, see home_assistant.md.
SET: 32
GET: 32800
Stored on FAN_LEVEL_IDS array as:
173, 174, 175, 176, 177, 178
Stored on FAN_LABEL_IDS array as:
78, 79, 80, 81, 82, 83
Stored on GLOBAL_SETTING_IDS array as:
48
| ID | Description | ON value | OFF value |
|---|---|---|---|
| 48 | Summer Ventilation | 0 |
800 |
The Fan pairs are ordered from top to bottom, and left to right.
| -- | -- | -- | -- |
|---|---|---|---|
| Level 173 | Level 175 | Level 177 | ℹ️ |
| Level 174 | Level 176 | Level 178 | ⚙️ |
Each Fan Pair can have a level from 0 to 11. There, just 0 to 6 are "real" levels, 7 to 11 are "special" levels. A Level of 255 means there is not fan in that pair.
| Level | Meaning |
|---|---|
| 7 | Burst Ventilation / Stosslüften |
| 8 | Automatic Humidity / Automatik Feuchte |
| 9 | Automatic CO2 / Automatik CO2 |
| 10 | Automatic Time / Automatik Zeit |
| 11 | Sleep / Schlummer |
| 255 | Not Connected |
The structure of the GET Message is as follows (special chars added manually):
[STX]32800[TAB]173[TAB]54142[ETX]
where:
32800is the command id for a GET request.173is the property id of the fan pair.54142is the checksum.
After a GET request message is sent, the SEC-TOUCH sends two messages backs, an ACK and the response of our request. This is how the full returned buffer looks like (special chars added manually):
[STX][ACK][ETX][STX]32[TAB]178[TAB]7[TAB]32627[ETX]
Where:
32is (probably) the command id that can be used to set the level of the fan pair.178is the property id of the fan pair.7is the value assigned to that id.32627is the checksum(?).
Byte received: 2 // STX 0x02
Byte received: 6 // ACK 0x06
Byte received: 10 // ETX 0x0A
Byte received: 2 // STX 0x02
Byte received: 51 // event_type?
Byte received: 50 // event_type?
Byte received: 9 // TAB 0x09
Byte received: 49 // id
Byte received: 55 // id
Byte received: 51 // id
Byte received: 9 // TAB 0x09
Byte received: 49 // value
Byte received: 48 // value
Byte received: 99 // TAB 0x09
Byte received: 52 // checksum?
Byte received: 50 // checksum?
Byte received: 54 // checksum?
Byte received: 57 // checksum?
Byte received: 54 // checksum?
Byte received: 10 // ETX 0x0A
Buffer: ��
�32 173 10 42696
💡 The Device expects for us to send an ACK after receiving that data.
💡 Sometimes we get an single 255 input value, we discard it as noise.
The structure of the SET Message is as follows (special chars added manually):
[STX]32[TAB]173[TAB]5[TAB]42625[ETX]
where:
32is the command id for a SET request.173is the property id of the fan pair.5is the value assigned to that id.42625is the checksum (probably).
Sadly (IMHO) the SEC-TOUCH just sends an ACK message after receiving a SET message and sometimes it takes a couple of seconds for the SEC-TOUCH screen to update the new value, so the best we can do is to wait for the ACK message and then send a GET message to do a security sync of the new value.
Byte received: 2 // STX 0x02
Byte received: 6 // ACK 0x06
Byte received: 10 // ETX 0x0A
git submodule update --remote --merge