Brawn1/ATTiny-Door-SensorDoor Sensor Battery based with Attiny84 and HC-12 Sender
Door sensor schaltplan is an open-source printed circuit board by Brawn1, from the Brawn1/ATTiny-Door-Sensor repository on GitHub. It is a 2-layer board of 46 × 66 mm with 19 parts on 22 nets, routed with 95 tracks and 1 via.
It is built around the ATTINY84A-PU. Its parts include 4 resistors, 3 connectors, 2 capacitors, 1 IC and 1 diode. It belongs with the sensors and measurement boards and the AVR (ATmega, ATtiny) boards of this library.
Batteriebetriebener Funksensor zur Überwachung einer Gefrierschranktür mit Alarm-Eskalation und Home Assistant Integration.
ATtiny84A + HC-12 Sender ~~~433MHz~~~> HC-12 + Raspberry Pi --> MQTT --> Home Assistant
(Sensor) (Empfänger)| Komponente | Pin | Funktion |
|---|---|---|
| Türkontakt (Reed) | PA3 | INPUT_PULLUP |
| HC-12 TX | PA1 | Bit-Banged UART 9600 Baud |
| HC-12 RX | PA2 | (nicht verwendet) |
| HC-12 VCC | PA4 | Stromversorgung über NPN (2N2222 + 1kΩ) |
| Piezo-Buzzer | PA5 | Alarm-/Warntöne |
| Status-LED | PB0 | Statusanzeige |
Stromversorgung: 3x AAA Batterien (4.5V frisch, ~3.0V leer)
| HC-12 Pin | Raspberry Pi |
|---|---|
| VCC | 5V |
| GND | GND |
| TX | GPIO15 (RXD) |
| SET | nicht verbunden |
| HC-12 Pin | Arduino UNO |
|---|---|
| VCC | 5V |
| GND | GND |
| TX | Pin 8 (SoftwareSerial RX) |
| RX | Pin 9 (SoftwareSerial TX) |
[0xAA] [0x55] [LEN] [DATA...] [XOR-Checksum]
Sync1 Sync2 Länge Nutzdaten Prüfsumme| Feld | Typ | Bytes | Beschreibung |
|---|---|---|---|
| type | char[16] | 16 | Nachrichtentyp als String |
| msg_type | uint8_t | 1 | Typ-Code (0x01-0x05) |
| device_id | uint16_t | 2 | Geräte-ID (Standard: 10) |
| sequence | uint16_t | 2 | Nachrichtenzähler |
| status_flags | uint8_t | 1 | Bit-Flags (s.u.) |
| value | float | 4 | Wert (kontextabhängig) |
| battery_mv | uint16_t | 2 | Batteriespannung in mV |
| door_open_seconds | uint16_t | 2 | Öffnungsdauer in Sekunden |
| Code | Name | Auslöser | Value-Inhalt |
|---|---|---|---|
| 0x01 | STARTUP | Einschalten | Protokollversion |
| 0x02 | CONTACT | Tür öffnen/schließen | 1.0 (offen) / 0.0 (zu) |
| 0x03 | VOLTAGE | Alle 5 Minuten | Batteriespannung in V |
| 0x04 | ALARM | Tür >90s offen | Sekunden seit Öffnung |
| 0x05 | HEARTBEAT | Testmodus (20s) | Uptime in Sekunden |
| Bit | Flag | Beschreibung |
|---|---|---|
| 0x01 | DOOR_OPEN | Tür ist offen |
| 0x02 | ALARM_ACTIVE | Alarm wurde ausgelöst |
| 0x04 | LOW_BATTERY | Batterie unter 3.6V |
| 0x08 | ERROR | Fehler |
Firmware flashen mit Arduino IDE:
code/code.ino# Abhängigkeiten
pip3 install paho-mqtt pyserial
# Serial aktivieren
sudo raspi-config # Interface -> Serial -> Login-Shell: NEIN, Hardware: JA
# Testen ohne MQTT
python3 receiver/python/door_sensor_v2.py --no-mqtt --debug
# Mit MQTT
python3 receiver/python/door_sensor_v2.py
# Als Systemd-Service installieren
bash receiver/create_service.shOptionen:
--debug Debug-Ausgaben (Hex-Dump, JSON)
--no-mqtt Nur Konsolenausgabe, kein MQTT
--port PORT Serial-Port (default: /dev/ttyS0)
--baud RATE Baudrate (default: 9600)Zum Testen und Debuggen ohne Raspberry Pi:
test/test.inoYAML-Dateien aus receiver/ in den MQTT-Config-Ordner kopieren:
home_assistant_config_binary_sensor.yaml - Tür-Status und Alarmhome_assistant_config_sensor.yaml - Batterie, Öffnungsdauer, SequenzMQTT-Topics unter bailey/tk/sensors/device_10/:
| Topic | Inhalt | Retain |
|---|---|---|
/door | OPEN / CLOSED | ja |
/alarm | ON / OFF | ja |
/battery_mv | Batterie in mV | ja |
/state | Komplettes JSON | ja |
door-sensor/
├── code/
│ └── code.ino # ATtiny84A Firmware (Sender)
├── test/
│ └── test.ino # Arduino UNO Empfänger (Test)
├── receiver/
│ ├── python/
│ │ └── door_sensor_v2.py # Python MQTT-Bridge (Raspberry Pi)
│ ├── create_service.sh # Systemd-Service Installer
│ ├── home_assistant_config.yaml # HA Config (kombiniert)
│ ├── home_assistant_config_sensor.yaml # HA Sensoren
│ └── home_assistant_config_binary_sensor.yaml # HA Binary Sensoren
├── kicad/
│ ├── door-sensor-schaltplan/ # KiCad Schaltplan + PCB
│ └── Fertigung/ # Gerber-Dateien für Platinenfertigung
├── HC-12_Datasheet.pdf
├── attiny_pinout.jpeg
└── README.mdKiCad-Projekt unter kicad/door-sensor-schaltplan/. Fertigungsdaten (Gerber) unter kicad/Fertigung/.
Privates Projekt.
| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | Jumper_2_Open | Jumper:SolderJumper-2_P1.3mm_Open_RoundedPad1.0x1.5mm | JP1, JP2, JP5, JP6 |
| 2 | 10k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R1, R2 |
| 1 | 100nF | Capacitor_THT:C_Axial_L3.8mm_D2.6mm_P7.50mm_Horizontal | C3 |
| 1 | 10µF | Capacitor_THT:CP_Radial_D4.0mm_P1.50mm | C1 |
| 1 | 1k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R4 |
| 1 | 220 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R3 |
| 1 | 2N2222 | Package_TO_SOT_THT:TO-92_Inline_Wide | Q1 |
| 1 | 4,5V-DC | TerminalBlock_CUI:TerminalBlock_CUI_TB007-508-02_1x02_P5.08mm_Horizontal | BT1 |
| 1 | ATtiny84A-P | Package_DIP:DIP-14_W7.62mm | U1 |
| 1 | Buzzer | Buzzer_Beeper:MagneticBuzzer_PUI_AT-0927-TT-6-R | BZ1 |
| 1 | IO-Analog | Connector_PinSocket_2.54mm:PinSocket_1x04_P2.54mm_Vertical | J2 |
| 1 | IO-Digital | Connector_PinSocket_2.54mm:PinSocket_1x04_P2.54mm_Vertical | J3 |
| 1 | SW_DPST_x2 | TerminalBlock_CUI:TerminalBlock_CUI_TB007-508-02_1x02_P5.08mm_Horizontal | SW1 |
| 1 | Sender | Connector_PinSocket_2.54mm:PinSocket_1x04_P2.54mm_Vertical | J4 |
| 1 | state | LED_THT:LED_D5.0mm | D1 |
It measures 46 × 66 mm and has 2 copper layers, 1.6 mm thick.
19 parts, built around the ATTINY84A-PU. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
From the Brawn1/ATTiny-Door-Sensor repository on GitHub, at the commit this page was made from: the board is kicad/door-sensor-schaltplan/door-sensor-schaltplan.kicad_pcb and its schematic kicad/door-sensor-schaltplan/door-sensor-schaltplan.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Its repository states no licence, so its author keeps all rights: ask Brawn1 before reusing the design.
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