Wiring up an LCD problem.

I have been learning a lot lately. Using perf board(should have used strip board!) boards with a sanguino is a pain and is hair ripping. I used female headers, the sanguino plugs into it and I'm finally done with.

Then I just figured out stranded wire is a pain to use when your trying to wire up a 20X4 LCD, I've used it a ton of times with my bread board and it was working wired but I think I pulled a pad, but I'm not totally sure. The contrast bars are showing, however no text is showing. I was removing the wires then soldering on longer ones, I'm ready to remove them all and redo it all. Should I use solid wire for this? Could I have killed my LCD by using a 2.7K resistor from the LCD's contrast set to ground? (That's what I've been using since I broke my 10K potentiometer. The contrast is perfect so I'm thinking it's not messed up)

If I pulled a pad should I very lightly sand the solder masked trace since I probably pulled my pad, then solder on a thin gauge of wire to it, finally then solder it(the small thin jumper wire from the trace) to the wire that's in the hole?

Sorry for the question, I've spent a few hours monkeying with it and getting close to tossing the LCD then try again since I'm questioning everything I've done.

Could I have killed my LCD by using a 2.7K resistor from the LCD’s contrast set to ground?

No that would be fine as long as it gives the contrast you want.

The only problem with solid wire is that it will break if flexed too much.

You sound to be on the right track, I can’t fault anything you are doing.

Best of luck.

The contrast bars are showing,
however no text is showing.

Can you explain exactly what you mean by this? And/or let us know what LCD you’re using and show us your code?

A typical HD44780 LCD will show black rectangles in the first line and nothing (spaces) in the rest of the screen if it’s powered up but not initialized. Hence, if you’re seeing a line of black boxes instead of the text you expected, it may be that your LCD is not being initialized correctly (could be a hardware or software problem).

Basically what was doing was cutting the wire in the middle, then splicing in the idle and finally using heatshrink for each joint. Then I'd turn on the sanguino and each time the simplistic hello world sketch(from the liquid crystal library that's everywhere, the pinout is the one found with the install of arduino software) would work. So the sketch loaded is fine, it has to be one of the data pins that's not where it should be(can't be it), I pulled a pad or I have a bad joint. I tested each pin then it's respective pin on the sanguino with a multimeter then crossed checked for shorts. Everything but the pin (I suspect) with the pulled pad is fine. While I was extending the wires out I eventually got the guts and cut 4 wires at once, then I had the issue. My second soldering job wasn't an A(thus maybe mechanically something went wrong), this is because I said forget it and removed most of the wiring I cut in half and ran continuous runs of wire. I don't see any shorts and I reheated all the joints, but since I have a few of the wires soldered onto the pads this could be the issue..

Here are some pictures of what I'm doing and the (I think) pulled pad, (Thus the wire isn't soldered there for now but it was and the LCD wasn't working) It didn't look as messy on the LCD side until I had a few choice holes with the solder stuck inside of them, it was really neat and I'm assuming a solder sucker would aid me with this issue.

I intend on figuring out how to remove the solder from the holes, bundling the wires in twos for ease of use then redoing it.........

It's for a reef controller that I've been working on for a few months, lots of learning experinces and not a ton of progress :-)





I intend on figuring out how to remove the solder from the holes

Solder sucker!

It's for a reef controller that I've been working on for a few months,

Check out these threads over on Reef Central:



Both have built in headers for LCDs. No perfboard soldering! :D

Okay I'll buy a solder sucker right now since I want to get the LCD working.

I have some female and male headers but I can't make it spatially work in the black cast acrylic box I built I've got tons of PCB clad, muratic acid, peroxide and such but for the life of me can't find a place to use a laser printer, so it's a sharpie(works great for some things) or stripboard(screwed up my order and got protoboard).

I'm rather close to finishing this and will use the perf board since it's not that bad, although I'll never use it again.

When I get the LCD working the rest is easy. I'm only 17 and am rather tight (the balance of nice looking, working well and cheap ), between the LEDs, sanguino, shipping to Hawaii and such I'm out $400+ for a 24 Cree array. I'm very close to finishing the controller portion I'll make it work.

The light will save me $100 a year and my tank won't spike to 85F, I've lost good amount of money from the heat of my MH.

First it was necessity then it went to more complex.

I'm having a LED moon controlled with some code that gets the lunar phase from the current date, PWM control of 6 channels of LEDs, storm code from DWZM, temperature control for the light, tank and such, a preset curve for light brightness, diy RTC, SD card data logger from broken camera, DIY CAT4101 drivers, multiplexer for PWM output, audible alarms, a basic but effective GUI(nice enough that I want to share it when it's perfected) and a few other things.....

I'm at RC under the username jm82792 :)

I rewired it using a piece of protoboard, soldered on a female header and made a quasi backpack. Now the LCD shows blocks of text where the characters would be, I'll double check my wiring again and it should work.

Okay I hit it with my continuity meter for the second time.(about two hours of fun rewiring it and such, hey I'm learning!) A hair sized wire was shorting out two pins!! Thanks a bunch, I'll post my whole setup when it's mounted in it's case and I've got some more code into it.