I'm new to arduino, and got a starter kit (it was not very good, gave 3 types of the same resistor and didn't even have the arduino board, I had to buy a separate one) so it didn't have instructions for the kit I got.
I've been messing around with the LCD for a few hours now and I cannot get further than having it display a bright backlight and a top row of white blocks. The pot works fine, when I rotate it the contrast changes. Everything is wired correctly I believe as it matches online guides I've read perfectly and I've seen a few posts with this issue and followed all of the steps they took, mine still won't work.
I haven't soldered the pins onto the LCD as I don't have a solder at the moment but as the display still lights up and responds to the pot I'm assuming this isn't an issue.
Attached is the diagram I have followed, only difference is I don't have a resistor attached as I don't have a resistor that can be attached there that allows the backlight to show (they are all the same with too high resistance).
I believe this should be working but it doesn't, can anyone help please?
I understand it being unreliable, but surely it should still show some sort of text when I upload the code? At the moment it shows nothing except the top row of white blocks
No, you actually have to connect all the functional pins, not just a few at random.
A couple of points. Do not connect the potentiometer to 5 V. If you must use a 10k potentiometer (a 1k is preferable) then connect both ends to ground. This corrects a longstanding error propagated through amateur designs and will make contrast setting easier.
It is most likely your display has resistor R8 as "101" which is 100 Ohms. As such, you do not need the 220 Ohm resistor on pin 15 unless you think the backlight is too bright. None of the I2C backpacks include it.
You intend to pursue electronics as a hobby? You must have for a start, a digital multimeter (a $5 one will do just fine for a start, or preferably two) and you must have a soldering iron and some practice with it. Or have a local "maker" place of some sort where people can share these.
No, a 1k potentiometer with the wiper to pin 3 on the display and one end only connected to ground will give you a particularly fine adjustment of the contrast over most of its range. Of course I mean that there will be a best point when the characters are bright white and the background blocks are only just visible, but there will be some display over most of the range.
Note that the contrast setting will almost certainly be at least slightly different when the display is actually initialised.
