Several commercial and industrial applications require a screen system to present data and receive parameters from the user. We can find them in applications for access control of environments, buses, industrial process monitoring systems and many other areas.
These systems are called Human-Machine Interface. Human-Machine Interfaces are extremely used to receive and present process information to users. It is through these systems that users are able to make adjustments to equipment process variables (speed, temperature, time, flow, pressure, etc.) and monitor them in real time.
In this article we will release a printed circuit board of a human-machine interface that can be used in numerous projects. The structure of the electronic board is shown below.
Below we will present the complete structure of the electronic board and how it can benefit your electronic projects.
The Electronic Structure of the Human-Machine Interface Board
The electronic structure of the board was developed from the electronic schematic below. This schematic is available for download at the end of this article, in the attachment area.
The electronic circuit is divided into 4 parts: power circuit, code transfer circuit, general purpose buttons, and JST connections for analog/digital inputs and outputs.
Next, we will discuss each region of the circuit.
Project Power Circuit
The power circuit consists of a Jack connector and the AMS1117-5V voltage regulator. This circuit is designed for an input voltage of 9V to 12V.
The figure above shows the Jack connector on the electronic board.
Below we have the electronic schematic of the power supply circuit.
Next, we will present the control circuit with the ATMEGA328P Microcontroller and the pins for code transfer in the circuit.
Circuit with ATMEGA328P Microcontroller and Code Transfer
The electronic schematic of the circuit is shown below.
In the figure above we have the ATMEGA328P Microcontroller, the circuit with the 20MHz crystal oscillator and the access pins (TX, RX, +5V, GND, DTR) to transfer the code to the Microcontroller.
Below we have the region of the electronic board with the circuit.
Now, we will present the circuit of the buttons. There are 5 buttons, 1 for reset, which is directly connected to the RESET pin of the ATMEGA328P Microcontroller. The 4 buttons are for general purposes, that is, you can use them to develop any functionality during the construction of your project.
See the electronic diagram of the button connections on the ATMEGA328P Microcontroller.
The buttons are connected in a pull-down configuration to the respective digital pins D9, D10, D11, and D12. These numbers are the Arduino digital pin numbers.
Below we have an image of the region of the electronic board with the 5 buttons.
Finally, we have the JST connectors to connect various devices in the electronic board circuit. See the board structure with all connectors.
Among the various connections, a JST connector was inserted to connect the LCD I2C. To facilitate the connection, holes were inserted for fixing spacers to fit the 16x2 LCD onto the structure of the electronic board itself. In the figure below you can see the result.
The LCD structure is fixed to the electronic board through 4 spacers. The figure below shows the spacers attached to the LCD holes.
Each spacer has a length of 12 mm. See its structure in figure below. Use screws for fixing the upper region and nuts in the lower region of the spacer.
All files from this project are available for download and you can earn 10 PCBWay units. Enter the website, create your account and receive 10 free units at your home.
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