i have a sparkfun serial 16x2 lcd (https://www.sparkfun.com/products/9066) that reads data from a light sensitive resistor . I also have a 2 channel relay that operated based on a value of the same resistor. the sketch for both of these items work on my arduino uno. I was having trouble with the relay itself, which is powered by a wall wart 5 v power supply. I came across this post in the arduino forum.
https://forum.arduino.cc/index.php?topic=185234.0
which included a great diagram how to wire the relay to isolate the power sources. Once i wired according to this diagram all was well with the relay. ( Removed jumper between VCC and JVCC, and wall wart + to JDVCC, wall wart - to grnd. Relay module powered from arduino 5v to relay VCC and grnd )
However, now my lcd , which had been working, is garbled and changes garbled characters every minute as the loop of the sketch runs.
The I found this , again in the arduino forum:
https://forum.arduino.cc/index.php?topic=327960.0
In this thread, one of the suggestions that seemed to work was:
LarryD suggests adding filtering on the LCD power pins… This means soldering a 10µF capacitor (with the correct polarity) between pins 1 and 2 of the display board itself. People have found these displays surprisingly sensitive to power fluctuations.
It seemed this was the correct forum to ask as its a sparkfun lcd. I have 2 questions. Will this solution work for this lcd ?
The documentations shows pin 1 as ground and pin 2 as 5v.
and second, I looked at the board to find pins 1 and 2 and find that they are not marked. It seems pins 1 and 2 depend on which side you are looking from. Which pins are 1 and 2? Thanks for your help.