I am using a 16x2 I2C LCD module in my arduino project. Below is the schematic.
below is my power supply
It was working fine till recently, but since some changes done which should affect the power consumption of the motor involved (increase), I am noticing a dip in the brightness of the LCD each time the motor switches on. I am using a Buck convertor which steps down the 12V of the arduino suitable 5V. I have checked the voltage at the output of this buck convertor and it is stable even when the motor is running. Interestingly If I connect the multimeter probes while the motor is running the sensor involved stops printing the readings to the screen.
I don't understand the reason for the dip in screen brightness when the voltage output of the buck convertor doesn't shift. Polarity is also protected by diode.
NEW FINDING: Ok, interesting development, I checked voltage directly at the LCD. While the Buck convertor output is still just 5.05 and doesn't budge with motor on or off, the voltage going to the LCD for some reason is just 4.73 and drops further to 4.5 when the motor starts. Why is that hapenning??
Another new finding: Buck convertor output when not connected to the system - 5.05V. When connected to the system - 4.89V. When Motor on, drops to 4.50V, rises to 4.7V, fluctuates between 4.6 and 4.77V.
It could be down to the wiring layout.
Have you tried using a star wire layout, where all the ground connections come from one place, and are not chained one to another.
You can also use star wiring on all the positive supply sources, but only those at the same potential.
The other thing is that if the buck converter was a cheap Chinese one, then they are often poor at supplying larger currents, even if they claim they can.
Yeah, I thought I might have to blame the buck convertor in the end, I really couldn't see anything else going wrong. There is no reason why without connection it reads 5.05V at output and after connection it reads 4.89V.
Hi,
Can you please draw a COMPLETE circuit diagram, there is so much missing, like the relay and the LCD, along with power supply, just connections unfortunately do not make the grade.
This is a troubleshooting process, so we need circuits that show ALL hardware and power supplies.
Even hand drawing can produce good results.
Can you please post images of your project so we can see your component layout.
I don't know what are SMPS power supplies but no where it is written on this one that this is SMPS. Could that be an issue? Are all power supplies naturally SMPS? This seems to be a fairly pretty one, I assumed it would be SMPS.
Since LM2596 converter is a switch-mode power supply, its efficiency is significantly higher in comparison with popular three-terminal linear regulators, especially with higher input voltages.
SMPS. Switch Mode Power Supply.
So you have the suitable power supply.
Have you got suitably gauged wiring for the high current loads?
Does the backlight dim or the contrast of the characters on the LCD screen?
Its a pump. Earlier the water source was placed higher and gravity was helping in the flow through the pump. Now the pump is higher and the pump has to pull.
The backlight dims. Interestingly the problem sorted itself out. That's the thing when the wiring isn't very neatly done, but has multiple joints, you never know where the issue could be.
