When reviving a luxmeter on a printed circuit board, there was a problem that the proposed connection is inoperative. The first option was quickly verified by measuring the printed circuit board with a multimeter. An error was found in...Electronics Projects, Arduino UNO Luxmeter Project (LCD USB) "arduino projects, " Date 2019/08/04
When reviving a luxmeter on a printed circuit board, there was a problem that the proposed connection is inoperative.
The first option was quickly verified by measuring the printed circuit board with a multimeter. An error was found in the wiring. Grounding of MCP1258 was not connected to dissolved ground. The defect was fixed, but the device was still inoperative.
The Arduino UNO programmer, in which the ATmega328 single chip is fitted, can provide not only 5V voltage, but also 3.3V power. When testing the power supply voltage change, I found that although all components are compatible with 3.3V, but the wiring is not able to work with such a small voltage. The problem could be that the selected components would need more current than 2 AA batteries to provide. By interrupting the PCB, it was experienced to power the circuit with 5V from the programmer. The interruption had to be made so that the voltage difference did not damage the components in the wiring.
With this in mind, it was found that the error had to be made in PCB design. Looking at the connection, I found that the flying capacitors of the MCP1258 I had designed badly. This error was corrected, but the luxmeter printed circuit board device remained inoperative. When checking components, it was found that the choice of MCP1258 stabilizer was unsuitable because this type cannot add enough current to the circuit. For a time reason, the new wiring design could not be implemented, so the luxmeter was left on the test panel because it was fully functional.
Luxmeter Graphics interface software
In the following, a graphical interface software has been designed so that the stored light intensity values can be transferred via the USB peripheral to the computer. A good solution is virtual serial communication (COM). In order for the virtual serial port to work properly, the AVR and PC parameters must be set appropriately.
Baud rate: 19200 bit / s parity: none data bits: 8, stop bits: 1, handshake: none.
When running the application, you need to select the communication interface (COM) that controls the reader. Communication settings are pre-defined, no need to be set. If the communication interface (COM) is not accessible because it is being used by another program, it will throw an error message. Until the serial port is busy, the program cannot be used.