Gym & 24/7 Fitness Club Access Control Hardware
Gym access control system hardware for 24/7 clubs: fob and wristband readers, face and QR terminals, anti-passback controllers and no-touch exit buttons.
ValenID · valenid.com · sales@valenid.com
LF-150 125 kHz RFID Module, UART TTL, 30 × 16 mm, External Antenna
30 × 16 × 8.9 mm EM4100-family reader with a 3.3 V TTL UART, auto or command-triggered reading and serial firmware upgrade, driven by an external 490 µH antenna.
- Reads EM4100, EM4102, EM4200, EM4305 and EM4450 credentials at 125 kHz
- UART at 3.3 V TTL levels, 9600–115200 bps (default 115200)
- Active auto-read mode or passive command-triggered read mode
- Firmware upgradeable over the serial port
- 30 × 16 × 8.9 mm, about 1.7 g as a bare board
- Frequency
- 125 kHz (EM4xxx)
- Interface
- UART, 3.3 V TTL
- Baud rate
- 9600–115200 bps (default 115200)
- Power
- 5 V DC, ≤ 120 mA
- Dimensions
- 30 × 16 × 8.9 mm (±1.0 mm)
- Antenna
- External, 490 µH ±10 µH
Reply within 24 hours Tested before dispatch Worldwide shipping
125 kHz RFID Module, UART TTL, 30 × 16 mm, External Antenna: overview
The LF-150 is a 125 kHz RFID module with a 3.3 V TTL UART, built for host-controlled designs in which the application decides when a card is read. The bare board measures 30 × 16 × 8.9 mm and weighs about 1.7 g. It reads EM4100, EM4102, EM4200, EM4305 and EM4450 credentials through an external antenna, so the coil can sit behind the user-facing panel while the board mounts wherever there is room.
Reading runs in either of two modes. In active mode the module polls for cards by itself and pushes each number to the host. In passive mode it stays idle until a read command arrives over the UART, which suits session-based equipment such as kiosks, vending machines and chargers. Baud rate is adjustable from 9600 to 115200 bps (default 115200), and firmware can be updated through the same serial link after installation.
Integration notes
Power and data share a 6-pin, 2.0 mm pitch header: 5 V DC, GND, TXD and RXD, with the remaining two pins (SCL/D1, SDA/D0) unused. The UART lines run at 3.3 V TTL levels, so check level compatibility with 5 V host logic. The antenna plugs into a 4-pin, 1.25 mm connector, and the specified coil inductance is 490 µH ±10 µH at 125 kHz. Current draw is up to 120 mA while reading and up to 100 mA in standby; the module operates from –20 to +60 °C at 20–80% RH non-condensing. No certification is listed, so compliance is assessed on the finished product. The 13.56 MHz HF-240 shares the 30 × 16 mm outline and the same 6-pin signal assignment, which makes it practical to plan one host board for either frequency; confirm connector positions against samples.
More features
- External 490 µH ±10 µH antenna on a 4-pin, 1.25 mm connector
- 5 V DC supply, ≤ 120 mA reading; operates from –20 to +60 °C
LF-150 specifications
RF & credentials
| Frequency | 125 kHz |
|---|---|
| Supported credentials | EM4100, EM4102, EM4200, EM4305, EM4450 and compatible |
| Antenna | External, 490 µH ±10 µH (at 125 kHz) |
| Reading modes | Active (automatic) or passive (on host read command) |
Interfaces
| Host interface | UART, TTL 3.3 V levels |
|---|---|
| Baud rate | 9600–115200 bps (default 115200) |
| Firmware update | Via serial port |
| Connectors | 6-pin 2.0 mm pitch (power/UART); 4-pin 1.25 mm (antenna); 2-pin 2.0 mm (not used) |
Electrical
| Supply voltage | 5 V DC |
|---|---|
| Operating current | ≤ 120 mA |
| Standby current | ≤ 100 mA |
Mechanical & environment
| Dimensions | 30 × 16 × 8.9 mm ±1.0 mm |
|---|---|
| Weight | Approx. 1.7 g (bare board) |
| Operating temperature | –20 to +60 °C (–4 to +140 °F) |
| Operating humidity | 20–80% RH, non-condensing |
| Storage temperature | –40 to +80 °C (–40 to +176 °F) |
| Certification | None listed for the module |
Connector pinout
| Pin | Signal | Function |
|---|---|---|
| P1-1 | 5V | Power supply, +5 V DC |
| P1-2 | GND | Ground |
| P1-3 | TXD | UART transmit (3.3 V TTL) |
| P1-4 | RXD | UART receive (3.3 V TTL) |
| P1-5 | SCL/D1 | No function |
| P1-6 | SDA/D0 | No function |
| P2 | ANT | External antenna connection |
| P3-1 | NC | No function |
| P3-2 | NC | No function |
P1: 6-pin, 2.0 mm pitch. P2: 4-pin, 1.25 mm pitch antenna connector. P3: 2-pin, 2.0 mm pitch.
Specifications can change between production batches. Confirm the current revision with us before placing volume orders.
Ordering options
Quote the SKU that matches your frequency, interface and mounting. Not sure? Send us your controller model and we will pick the variant for you.
| SKU | Configuration | Actions |
|---|---|---|
| LF-150-E-T | 125 kHz EM module, 30 × 16 mm, UART (3.3 V TTL) interface, external antenna connector |
Where the LF-150 is used
- EV chargers or vending controllers that request a card read only when a session starts
- Handheld data terminals reading EM4100 tags over a 3.3 V microcontroller UART
- Keyboards, PCs and service kiosks with an operator-login badge reader
- Ticketing or fare-collection equipment with the antenna behind the front panel
RFID for EV Charging Stations: Modules, Cards & Fobs
EV charger RFID cards, key fobs and 13.56 MHz reader modules for charger OEMs and operators: UID formats, OCPP idTag mapping and UART integration notes.
LF-150 FAQ
What is the difference between active and passive reading?
In active mode the module reads continuously and reports cards automatically. In passive mode it reads only after the host sends a read command over the UART.
Can I connect it directly to a 5 V microcontroller?
The module is powered from 5 V DC, but its TXD and RXD lines use 3.3 V TTL levels. Confirm your MCU accepts 3.3 V inputs, and use level shifting if your host drives its TX line at 5 V.
What antenna does the module need?
An external 125 kHz coil with 490 µH ±10 µH inductance, plugged into the 4-pin, 1.25 mm antenna connector.
Can the firmware be updated after installation?
Yes. The module supports firmware upgrades over its serial port.
Which cards does it read?
EM4100, EM4102, EM4200, EM4305 and EM4450 credentials and compatible 125 kHz cards and tags.
Before you buy
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Get pricing for the LF-150
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