FM transmitter SENCOR SWM 3535 BT — car handsfree and MP3 player with Bluetooth

SENCOR SWM 3535 BT is a compact car FM transmitter that integrates Bluetooth handsfree functionality with MP3 playback for in-vehicle audio streaming. It connects to the car power socket and transmits audio from a paired smartphone or from local storage (USB flash drive or TF/microSD card) to the car radio via FM frequency. The unit supports handsfree phone calls through its built-in microphone and provides simple controls for play, pause, track selection and volume. A yellow non-shining LED display shows the selected FM frequency, track number and basic status information.

Advantages

The device supports Bluetooth V4.2 for wireless streaming and call handling, plus direct playback from USB flash drives and TF/microSD cards up to 32 GB. Two USB slots are provided — one dedicated for MP3 music playback and one main USB port for charging devices up to 5 V / 2.4 A. The transmitter stores the last used frequency, track number and volume level to simplify repeated use. Additional features include a built-in microphone for handsfree calls, digital tuning across the FM band and a voltage meter to monitor the car power supply.

Suitable for

• Drivers who want handsfree phone calls while keeping both hands on the wheel
• Cars without auxiliary input or Bluetooth stereo who need wireless audio streaming
• Playing MP3, WMA, FLAC or WAV files from USB flash drives or TF/microSD cards during travel
• Charging mobile devices from the vehicle while playing audio

Key specifications

• Wireless standard: Bluetooth V4.2
• Supported audio formats: MP3, WMA, FLAC, WAV
• Storage support: USB flash drive and TF/microSD card (up to 32 GB)
• USB ports: two slots (one for MP3 playback, one main for charging)
• USB charging output: DC 5 V / 2.4 A max
• FM transmit range: 87.5 – 108 MHz (206 available frequencies)
• Power supply: DC 12 / 24 V via car power plug
• Display: yellow non-shining LED frequency and track display
• Controls: play/pause, previous/next, volume control, frequency tuning
• Dimensions (W×H×D): 38 × 70 × 48 mm; Weight: 27 g
• Built-in microphone for handsfree calls; memory of last frequency, track and volume

How to use

Insert the transmitter into the car power socket, set the transmitter to an unused FM frequency and tune your car radio to the same frequency. For Bluetooth streaming, enable Bluetooth on your phone and pair it with the SENCOR SWM 3535 BT; audio and calls will route through the car stereo. For local playback, insert a USB flash drive with MP3/WMA/FLAC/WAV files or a TF/microSD card (up to 32 GB) into the appropriate slot; use the unit controls to play, pause and change tracks. Use the main USB port to charge a mobile device as needed. The transmitter remembers the last used frequency, track and volume after power off.

Usage recommendations

Select an FM frequency that has minimal radio interference in your area to ensure clear audio transmission, and position the transmitter so the built-in microphone is not obstructed for better call quality. Use a properly formatted USB drive (FAT32) and keep firmware and phone Bluetooth settings updated for optimal compatibility. Avoid occupying the car power socket with multiple high-draw chargers simultaneously to prevent power issues.