The SM-028 is a Wi-Fi+BLE dual-protocol module developed by eWelink. It is composed of a highly integrated wireless radio frequency chip and a small number of peripheral devices. The module operates in the 2.4GHz frequency band, supports the 802.11 b/g/n wireless standards, and is powered by a single 3.3V power supply. This enables the module to be flexibly applied to various consumer products, maximizing the ability to meet customers' needs.
The SM-028 module is suitable for smart home applications, smart appliances, or intelligent lighting control.
Product Features
- Built-in low-power 32-bit CPU, which can also be used as an application processor.
- Support for the 802.11 b/g/n wireless standards.
- WPS, WEP, WPA /WPA2 Personal /WPA2 Enterprise /WPA3 security modes.
- PWM control.
- Support for timer operations.
- Support for remote Wi-Fi control.
- Support for compatible pairing mode / Bluetooth pairing.
- Support for OTA (Over-The-Air) upgrades.
- Support for 2.4G light intelligent control.
- Local area network control.
- Compatibility with smart speakers such as Alexa, Google Assistant,
II. Function Description
When the SM-028 module is online, you can control the module's switch via the EWeLink APP. When the mobile phone and the module are in the same local area network, you can also control the module's switch through the local area network. The SM-028 module also supports 2.4G light intelligent remote control, and its switch can be controlled by a learned remote controller.
III. Electrical Characteristics
Rated Parameters
Conditions: VDD = 3.3V ± 10%, GND = 0V; tested at room temperature of 25°C.
Model. : SM-028
Hardware Interface : PWM, IIC , GPIO
Operating voltage: 3.0V~3.3V
Operating current: Average current: ≈45mA,
Maximum operating current: 350mA
Operating temperature: 0°C~45°C
Storage environment:
Temperature: -10°C~75°C,
Relative humidity: 20%RH~80%RH
Wireless network type: wifi: STA/AP/STA+AP
Bluetooth: Bluetooth 5.0
Security mechanism: WPS, WEP, WPA /WPA2 Personal /WPA2 Enterprise /WPA3 Encryption type: WEP64/WEP128/TKIP/AES 128/192/256
Firmware upgrade: OTA remote upgrade
Wi-Fi Parameters
Conditions: VDD = 3.3V ± 10%, GND = 0V; tested at a room temperature of 25°C.
Wireless Standard: IEEE 802.11b/g/n
Frequency Range:
wifi: 2412-2482Mhz
BT: 2.400GHz to 2.4835GHz
Transmit Power
802.11b: 19±1dBm (@11Mbps)
802.11g: 16±1dBm (@54Mbps)
802.11n: 16±1dBm (@HT20,MCS7)
Receive Sensitivity
802.11b: -92 dBm (@11Mbps ,CCK)
802.11g: -76 dBm (@54Mbps, OFDM)
802.11n: -72 dBm (MCS7)
Antenna Type: PCB Antenna
III. Module Type and Pin Definition![]()
Pin Arrangement Order
3V3: Module power supply DC 3.3V
GND: Module Negative pole
22: Relay 3 switch control signal output, high level effective. The default is low level, and it is high level when turned on.
17: Relay 2 switch control signal output, high level effective. The default is low level, and it is high level when turned on.
C: Relay 1 switch control signal output, high level effective. The default is low level, and it is high level when turned on.
W: Relay 4 switch control signal output, high level effective. The default is low level, and it is high level when turned on.
R: Button control 4 input, default high level. Low level effective. Pulling it low for more than 5 seconds enters the pairing mode.
G: Device status indicator light output, high level effective. Connect a 1K current-limiting resistor in series externally to the ground.
B: Button control 1 input, default high level. Low level effective. Pulling it low for more than 5 seconds enters the pairing mode.
A: Button control 2 input, default high level. Low level effective. Pulling it low for more than 5 seconds enters the pairing mode.
L: Button control 3 input, default high level. Low level effective. Pulling it low for more than 5 seconds enters the pairing mode.
