Summary of HC-12 433MHz wireless serial communication module configuration
HC-12 are affordable 433 MHz wireless serial modules (based on the SI4463) providing UART radio links up to 1800 m in open space. They support 100 selectable channels from 433.4 MHz to 473.0 MHz, external antenna, 3.2–5.5 V supply, and 3.3 V/5 V UART. Configurable via AT commands, HC-12 offers multiple serial baud rates and four operation modes (FU1–FU4) trading throughput for range; FU4 yields longest range (1800 m) at very low airspeed and packet size limits. Paired modules must share mode and speed.
Parts used in the HC-12 wireless serial link project:
- HC-12 433MHz wireless serial communication module (x2 for a link)
- External antenna (compatible with HC-12)
- Power supply 3.2V–5.5V (battery or regulated supply)
- Microcontroller or UART-capable device (3.3V or 5V UART)
- Wires or connectors for VCC, GND, TX, RX
- Optional level shifter (if needed for voltage matching)
HC-12 are cheap 433MHz wireless serial port communication modules with a range up to 1800m in open space. Each costs about $5 when bought from China, and 2 of them can create wireless UART link that can be used, for example, to transfer telemetry data from UAV. Or drive IoT device. Or connect sensors. Or whatever else one can think of.
It is based on SI4463 RF chip, has build in microcontroller, can be configured using AT commands and allows to use external antenna. Working frequency is divided into 100 channels starting from 433,4MHz up to 473,0MHz with 400kHz channel separation. Maximum output power is 100mW (20dBm) and receiver sensitivity differs from -117dBm to -100dBm, depending on transmission speed. It accepts 3,2V-5,5V power supply and can be used with 3.3V and 5V UART voltage devices (3.3V safe).
HC-12 serial port supports following baud rates:
- 1200bps
- 2400bps
- 4800bps
- 9600bps (default)
- 19200bps
- 38400bps
- 57600bps
- 115200bps
Each HC-12 can work in one of following modes:
- FU1 – moderate power saving mode with 250000bps “over the air” baud rate. Serial port baud rate can be set to any supported value
- FU2 – extreme power saving mode with 250000bps “over the air” speed. Serial port rate is limited to 1200bps, 2400bps, 4800bps
- FU3 – default, general purpose mode. “Over the air” speed differs depending on serial port speed. The same goes for maximum range:
- 1200bps ~ 1000m
- 2400bps ~ 1000m
- 4800bps ~ 500m
- 9600bps ~ 500m
- 19200bps ~ 250m
- 38400bps ~ 250m
- 57600bps ~ 100m
- 115200bps ~ 100m
- FU4 (available in version 2.3 or newer) – long range mode. “Over the air” speed is limited to 500bps and serial port speed to 1200bps. Because air speed is lower than port speed, only small packets can be send: max 60 bytes with interval of 2 seconds. In this mode range is increased to 1800m.
Pair of HC-12 that creates a wireless link has to work in the same mode (FU1, FU2, FU3, FU4) and with the same speed.
For More Details : HC-12 433MHz wireless serial communication module configuration
- What frequency range do HC-12 modules use?
They operate on 100 channels from 433.4 MHz up to 473.0 MHz with 400 kHz channel separation. - Can HC-12 work with 5V UART devices?
Yes, HC-12 accepts 3.2V–5.5V supply and can be used with 3.3V and 5V UART voltage devices. - How are HC-12 modules configured?
They are configured using AT commands. - What maximum range can HC-12 achieve?
In FU4 long range mode the range increases to 1800 m in open space. - Do paired HC-12 modules need the same settings?
Yes, a pair must work in the same mode (FU1–FU4) and with the same speed. - What serial baud rates are supported by HC-12?
Supported rates are 1200, 2400, 4800, 9600 (default), 19200, 38400, 57600, and 115200 bps. - Which HC-12 mode gives the highest throughput?
FU1 and FU3 offer higher over-the-air speeds (FU1 has 250000bps air speed; FU3 varies with serial speed). - What are the limitations of FU4 mode?
FU4 limits over-the-air speed to 500 bps, serial speed to 1200 bps, and allows max 60-byte packets with 2 second intervals.
