Microduino-Module BM Shield

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Microduino Module BM Shield is a single lithium battery microusb charging and discharging management module, which is used with the cooperation of Microduino-Module_BM_Li-ion, and it has functions such as under voltage and changing and output indicator.


  • Charging and discharging management, and charging indicator and under-voltage indicator;
  • Small, cheap, flexible and open;


  • Look at the interfaces of the module at first:
    • A two dial switch, which is used to control whether output voltage(5V and 3.3V);
    • A microusb interface, which is used to supply power or charge the lithium battery;
    • There is a double color indicating light on both sides. The left is used as the voltage indicator, and the right is used as the power supply indicator;
    • A 1.27-spacing 4Pin interface (which is connected to "VUSB","SWI","BAT" and "GND" of Microduino-Module BM Li-ion,correspondingly);

Introduction of pins



  • Plug microusb and charge the lithium battery with 600ma current. And at the same time, connect Microduino-Module BM Li-ion with 4pin cable, to provide 5v and 3.3v output;
  • Plug microusb. If the lithium battery is connected and the voltage of the battery is lower than 4.2V, the left light will emit yellow light. When the lithium battery is fully charged to 4.2V, the left yellow light will turn out;
  • When the voltage of the lithium battery is as low as 3.6V, the left light will emit red light to show the current electricity is little;


  • Plug microusb and dial the two dial switch to the right (namely the side with "+"). No matter whether the lithium battery is connected, the right emits red light. If it is connected, Microduino-Module BM Li-ion will provide 5v and 3.3v voltage;
  • When the lithium battery is connected and the two dial switch is dialed to the right(the side with "+"), the right light will emit yellow light. If the Microduino-Module BM Li-ion is connected, it will provide 5v and 3.3v voltage;


PCB File:BM Shield.rar

Main Component


  • Battery:Single 3.7v lithium battery;
  • It is suggested that connect the battery and the module with 2PIN Dupont;
  • Microduino-Module BM Li-ion;
  • The recommended choice of the power supply:5V voltage, above 600ma current, such as:USB of computer and 5V phone charger;
  • 1.27-spacing 4PIN cable;


  • Lithium battery charge



Micrmodule BM Front
Micrmodule BM Back