Introduction: Mini PLC

About: Creator of content on YouTube, I develop technologies for elevators and also for my channel

The Mini PLC card consists of a card developed by the Jefferson Bueno Channel on YouTube and allows you to use learning in low cost programming in relation to PLC commercials.

The aim is to create an open software and open hardware product with commercial components of easy access.

A very practical and didactic circuit that can be used for learning or even in a final project.

Jefferson Bueno Channel


Componet List Mini PLC

Resistors (1/4W)

- 13 resistors 10K ohms

- 27 resistors 2k2 ohms

- 6 resistors 1k ohms


- 2 capacitors ceramic 22pF

- 1 capacitors ceramic 100nF

- 1 eletrolític capacitor 2200uF x 16V


- 6 transistors BC557 (PNP)

- 6 transistors BC547 (NPN)

Diode and LED´s

- 5 diodes 1N4007

- 6 difuse led´s yellow 3mm

- 4 difuse led´s green 3mm


- 1 crystal 16MHZ


- 1 IC ULN2003APG

- 1 IC 7805


- 1 DIP Switch 6 way

- Tactile Button 6x6x4,2 2T


- 1 Socket 28 pins Slin

- 4 Relays 24VCC 5 pins

- 2 Terminal Block 5mm / 6 way

- 1 Terminal Block 5mm / 8 way

- 1 Terminal Block 5mm / 2 way

- 1 Terminal pins witch 40 pins

- 1 Buzzer 5VCC

Step 1: Knowing the Basic Operation

The board has 06 (six) pre-selected 24Vdc digital inputs and 05 (five) is also allowed (four for output and one for bell), in addition to having 06 (six) 5Vdc digital ports where the user uses in its programming if the digital input or output, if using these digital ports, as input it will enable PULL-UP resistors by means of the DIP, leaving it ON and if it is going to be used as an output, leave the DIP for the port in OFF.

Step 2: Using the Arduino on the MINI PLC

The Mini PLC allows programming in Ladder and also in C Aduino Language. It has six inputs prescribed on pins 4/5/6/11/12/13 of the Atmega328P microcontroller and five outputs using pins 23/24/25/26/27 of the microcontroller the four first pins are dedicated for the relays and the last for the buzzer. Still, there are six digital ports (pins:14/15/16/17/18/19) that can be programmed as input or output, being 5VDC different from the prescribed 24VDC inputs. If you want to use these digital ports as inputs, you can use the pullup resistors that can be connected via the SWITCH DIP and use it as an output, just turn off the pullup DIP. To start using, you need an Arduino Uno R3 connected to MiniPLC and after finishing the software you can leave the Arduino connected or remove the Atmega328P from the Arduino and connect it to the 28-pin socket of the MiniPLC board.

Step 3: Software and Programming

As the circuit is based on the use of Arduino UNO, its programming can be done through the Arduino's own software as well as a LADDER software can be created by LDMICRO, which in case AVRDUDES is necessary to record the HEX file generated in LDMICRO.

Thus enabling the programming in C programming language and also in LADDER language.

Step 4: Open Hardware

The option to create an open softawe circuit comes from the need to integrate people and allow everyone to download files and assemble their own PCBs. Making it even easier to learn or awaken the interest of young people and adults to the world of electronics.

The available files are free to choose where they want to have the PCBs produced and also accompanies the list of circuit components. On the PCB itself, the IDs of the components are recorded together with their respective values that make assembly even easier.

Step 5: JLCPCB Prototype & PCB

JLCPCB has been operating for over ten years producing PCBs of excellent quality making your project more professional. With the order of your PCB your project having the size of 100x100mm five PCB´S for only $ 2 and you can still choose among the colors available for your project.

The Jefferson Bueno channel uses the services of JLCPCB and recommends it to everyone.


Step 6: Video Lessons About the MINI PLC

On the Jefferson Bueno channel you can find the complete playlist on programming and use of the MINI PLC. Join the channel and stay on top of each new video.

MINI PLC playlist

Step 7: MINI PLC Presentation Video

Watch the MINI PLC presentation video