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PKB Bluetooth module designed specifically for Bluetooth speaker products. With high integration, small size and other features, just with a few external components to achieve its powerful. To establish a connection with A2DP, AVRCP transmission and remote control protocol any Bluetooth audio device (such as: Bluetooth-enabled mobile phone, computer, Bluetooth adapter, etc.), the wireless receiver to achieve high-quality stereo audio stream, and on the audio player remote control.

PKB Bluetooth stereo receiver modules to provide users with a remote control button interface, work status indication interface, stereo audio output interface.

Pairing info

  • Module Name BT-Speaker
  • Module pairing code 0000
  • 115200 baud
  • Module size: 14x23mm
  • Operating voltage VBAT: 3.4 - 4.2V
  • Power Comsumption: Operational ‐ Less than 26 mA (active) ; Idle (slee p) < 1.0mA


  • Various types of high-quality Bluetooth stereo audio receiver equipment.
  • Various types of high-quality Bluetooth stereo speakers, stereo.


Pin definitions

Pin number Pin definition Output/Input Description
1 GND Input/Output To GND
2 GND Input/Output To GND
3 SPKN Output Stereo differential output negative terminal
4 SPKLP Output Stereo left channel differential output positive terminal
5 SPKRP Output Stereo right channel differential output positive terminal
6 GND Input/Output To GND
7 MIC Input MIC input
8 VMIC Output MIC Power
9 BLED Input Working status LED, normally to blue LED
10 CHG Input Lithium battery charging status LED
11 RLED Input charging status, matching status etc, Normally to red LED
12 VBAT Input Lithium battery Positive terminal (to power positive)
13 GND Input/Output To GND
14 GND Input/Output To GND
15 MFB Input On/Off switch (long press)/answer Phone/Stop playing (short press)
16 VOL+ Input Volume up control
17 VOL- Input Volume down control
18 RST Input Reset
19 TXD Output UART TTL Signal output
20 RXD Input UART TTL Signal input
21 FWD Input Play next song
22 BACK Input play previous song
23 MUTE Output Mute (Low TTL for mute, high TTL for nong-mute)
24 1V8 Output 1.8V power output
25 GND Input/Output To GND
26 GND Input/Output To GND

Performance Specification

  • Power consumption: less than 26 mA (active), less than 1mA when idle.
  • External Antenna via SMT pads

Reference circuit

PCB LAYOUT Design Note

  • Power supply decoupling capacitor should be located close to the module pins.
  • Module substrate should be fully paving (antenna below can not paving), and covered with insulating white oil in the position of the substrate.
  • Audio circuit ground should be separated from the other ground, and then fully connected at the power ground after the separate circuit design.
  • The module ground should be separated from the other ground at the power ground traces alone sufficient grounding.
  • All ground should have a large number of copper paving, and the more via holes the better.
  • The antenna placed as far as possible, the best place is the edge of the base plate, the antenna should not close to any metal objects, to ensure good communication with the outside world. Preferably, the antenna protrudes the bottom board, or keep empty below the antenna.

Demo Board

Pin Definition:

PKB-PCBA dimension.jpg
  • TXD: Serial signal input
  • RXD: Serial Signal output
  • VIN: Power input (lowest to 4.5V, classical 5V, highest to 10V)
  • GND: Power Ground
  • RO: right sound channel output
  • GND: To ground
  • LO: Left sound channel output
  • LED: To LED negtive, LED postive serial connect with resistor to VIN

How to use

  • The module name is BT-Speaker
  • Pairing password is 0000
  • Must be strictly in accordance with the reference diagram wiring
  • Search our module, when powered up, with a Bluetooth mobile phone or computer Bluetooth, and pair connection.Very very Simple.