BMini shield

From Biemme Italia Wiki
Jump to: navigation, search



Bminishield rev1.jpg

Code, plug and use it, make your house, industry and office more efficient and clever.

Bmini shield is an advanced expansion board designed specifically to extend the power of Arduino. It lets you create an independent and intelligent unit that controls motors, reads temperature probes, dims leds, manages 24VDC digital inputs, solenoid valves, bulbs, etc. Feel free to connect as many bMini shield as you want in a network of intelligent devices (but not only bmini shields) that can easily communicate through RS485 and Ethernet interfaces.

Design your own protocol or use the libraries for modbus RTU and TCP. Create a lightweight webserver that allows you to control remotely the BMini shield.

The design, engineering and production is completely made in Italy. IT flag.png

How it works

Program your Arduino Mini, Ethernet or UNO board, plug it into the BMini and power the shield. That's it.

API and Libraries

In order to leverage the power of the Bmini shield and to simplify its use, we provided the following Arduino libraries and tutorials:


Four infographics on the Bmini shield are available:


Power supply

  • 24V DC or AC
  • Separated power input for the MCU and for the digital inputs. No electrical noise and current peaks will alter the Arduino board
  • 2 fuses for the supply voltage
  • 5V power output for external sensors
  • 24V power supply with two different terminal block connector plug IN/OUT configuration. Connect the 24V to the first bMini (J3 connector) and use the J4 for powering the following bMini in the network


  • 4 high quality relay out­puts (max 8A) together with 4 fuses
  • 4 opto iso­lated dig­i­tal inputs
  • 8 ana­log inputs (0-5V) (can be used as digital inputs)
  • 2 PWM outputs
  • I2C bus
  • 4 leds for digital inputs status



  • The maximum length and width of the BMini shield are 16.5 cm and 11 cm (6.4 in and 4.3 in respectively)
  • Easy to mount in home automation or industrial existing structures using the plated through holes in the PCB.

PCB Components Layout

Bmini components layout.jpg

Pin mapping

The Bmini shield has a MCU socket that supports different types of Arduino Boards. You can decide to use the one that you prefer and that best meets your needs. It natively supports the Arduino Mini Board and for the other boards, a socket converter is available.

In the following, you will find the pin mapping for the Arduino Boards supported. Please note that since Arduino features might vary from one board type to another, this might limit the availability of some hardware characteristics. However, the most important ones like relay digital outputs, digital inputs, RS485 bus and analog inputs are common no matter which Arduino board you choose.

Warning LEDs

LED# Description Notes
LD1 Power input +9V Arduino Mini -
LD2 Power input +5V aux -
LD3 Digital Input 4 -
LD4 Digital Input 3 -
LD5 Digital Input 2 -
LD6 Digital Input 1 -
LD7 Modbus Communication Status -
LD8 Digital Output 1 -
LD9 Digital Output 2 -
LD10 Digital Output 3 -
LD11 Digital Output 4 -

J6 Connector

Designed for two pwm outputs.

Pin Description Notes
16 +5V -
17 PWM 1 -
18 PWM 2 -
19 0V -

J5 Connector

Designed for 4 digital inputs (use clean contact). See the infographic on that topic.

Pin Description Notes
1 Digital input 1 -
2 Digital input 2 -
3 Digital input 3 -
4 Digital input 4 -
5 Common +24 VDC/AC -

J3-J4 Connectors

Power inputs (to be separated from the power input of the board). See the infographic on that topic.

Pin Description Notes
12 +24 VDC/AC -
13 0 VDC/AC -
14 +24 VDC/AC -
15 0 VDC/AC -

J1-J2 Connectors

Board Power input (electrical tension 24 VDC/AC). See the infographic on that topic.

Pin Description Notes
11 in +24 VDC/AC -
10 in 0 VDC/AC -
9 out +24 VDC/AC -
8 out 0 VDC/AC -

J3 Connector

Bus rs 485

Pin Description Notes
6 RS485 bus -
7 RS485 bus -

J9-12 Connectors

Clean contacts. See the infographic on that topic.

Pin Description Notes
20 NC -
21 COM Clean contact max 8A
21 NO -

The pins sockets that are connected to J7 and J8 connectors depends on the Arduino board you use. Take a look at


Please take a look at the BMini shield rev1 FAQ section.


Example of communication between a bMini Shield and Ltouch F Android panel/tablet.
  • Control motors, bulbs, valves, solenoid valves
  • Control automatic gates, automatic doors
  • Read temperature
  • Managing input signals from a free contact such as switches, relay, safety limit switches, sensors etc



This documentation is licensed under the Creative Commons Attribution-ShareAlike License 3.0

Personal tools