Introduction¶
The WattWächter TTL is a pure IR reading head designed for makers and tinkerers. The device contains only the transmit and receive electronics – an external evaluation unit is required for control and data processing. This provides maximum flexibility for custom projects.
Use Cases¶
The WattWächter TTL is designed as an expansion module in combination with:
- WattWächter WiFi/USB (cascading up to 4 devices)
- D1 Mini / ESP8266
- ESP32
- Raspberry Pi
- Arduino
- Other microcontrollers with a TTL interface
WattWächter WiFi/USB Gen 2
The WattWächter WiFi/USB Gen 2 no longer supports connecting a WattWächter TTL. Cascading is only possible with the first generation of the WiFi/USB.
Concrete examples with wiring diagrams and source code can be found under Integrations → Arduino / ESP32 and Integrations → Python.
Features¶
- Reading and transmitting meter data via infrared
- TTL interface with RX / TX
- Operating voltage 3–5 V (directly compatible with 3.3 V and 5 V boards, no level shifter needed)
- Built-in reverse polarity protection
- Strong neodymium ring magnet for secure attachment to the meter
- Screw terminals – no soldering required
- Approx. 1 m connection cable pre-installed
Connection¶
The WattWächter TTL connects to your evaluation electronics via 4 wires (screw terminals, 1:1 wiring) and operates at 3–5 V. Data is transmitted serially at 9600 baud (SML).
For the full pinout and wiring, see Getting Started → Wiring.
Package Contents¶
- WattWächter TTL IR read/write head
- Approx. 1 m pre-installed connection cable
- Quick-start guide with QR codes
Additionally required:
- Evaluation electronics (D1 Mini, ESP32, Raspberry Pi, etc.)
- Custom firmware/software
- Programming knowledge
- A prepared electricity meter (PIN from grid operator)
Technical Specifications¶
| Property | Specification |
|---|---|
| Dimensions (D × H) | Ø32 mm × 21 mm |
| Weight | 25 g |
| Magnetic holding force | approx. 8.5 kg |
| Housing material | PLA |
| Data transfer | TTL RX / TX |
| Power supply | DC 3.3–5 V |
| Connection | Screw terminals (4-pin) |
| Cable length | approx. 1 m (pre-installed) |
| Power consumption | < 0.5 W |
| Operating temperature | 10 °C – 50 °C |
| IR LED wavelength | 850 nm |
| Photo sensitivity | 880–1120 nm |