raspbian lcd displays random characters quotation

Many of these LCD controllers differ slightly from the HD44780 controller in things like the initialization sequence, minimum delay between commands and maybe other ways I don"t know of.

try putting a 1n4148 diode between the 5V supply and the 5V of the LCD, so the LCD will get around 4.5V, that is enough for the LCD, and lowers its logical input levels enough so that it sees 3V3 logic highs as "1" reliably. The garbled letters, and blocks are due to the LCD sometimes seeing a "1" as a zero and that corrupts all communication between the PI and the LCD.

Its a well know problem when trying to drive an LCD with 3V3 levels, it actually needs minimally 3.5V when its powered with 5V (70 % of VCC = 0.7 x 5.0 = 3.5).

In the photos above the Pi is a Model B Rev 2 so should work fine with my tutorial. Random characters is usually a sign it has not been initialized correctly. Again this could be caused by intermittent connections.

I was having the same problem as the OP on my current build with an I2C back-packed LCD getting corrupted. I"d tried all kinds of things to fix the problems - changing the delays, trying different libraries, and pulling out hair with no joy in fixing it.

For anyone else with this problem, you may have what I have if you"re doing event-driven code e.g. from from a switch or rotary encoder. I was getting events triggered while the python code was trying to communicate with the LCD screen - which themselves tried to write to the LCD.

I also had the same problem with scrambled characters on my display. I found that there was a short between the data lines on the expander board where it is soldered to the display board. Once I cleaned up the messy solder, the display worked perfectly.

My LCD is showing random characters, see the picture below (the last character blinks, some characters change and over time there are slowly more and more characters). I"m starting to wonder if the LCD I chose has a driver compatible with the LiquidCrystal library, what do you think? If so what can I do to avoid buying another one?

My code seems to work for outputting to the console, however when I try to output to the LCD, it gives some weird characters and stops. Not sure what to do as i"m not a python wiz (you"d think id be more like php, but nah lol).

This particular post will cover a bit of technology that most people simply know as "the LCD display". I"m not talking about the computer monitor type of LCD display; no, I"m talking about that small screen on many common pieces of electronics, the one that looks like this.

I"m going to talk about the LCM1602C LCD. The purpose of this post is to get away from a lot of the esoteric "how tos" of this particular display. Ya see, this display is based on the Hitachi HD44780 LCD controller. The nice thing about that is the specifications are readily available. The problem is that the specifications are not readily understood. Yes, I believe that this is an example of "lost in translation".

Let"s talk about the display first. This particular display is a 16 character by 2-line display. Its memory can hold up to 80 characters, 40 on each line of the display. The actual part that displays the characters can only show 16 characters across at any one time. Using the SHIFT command, you can move the part of the lines that are displayed.

I used an Arduino to drive my LCD display simply so that I could drive the various logic lines. I didn"t use any of the specialized Arduino libraries for driving a LCD; instead, I simply used the standard digitalWrite command to send the commands and data. The digitalWrite command merely sets the targetted output pin to either 0 V (GND, or LOW) or to +5 V (HIGH). This is equivalent to opening (LOW) or closing (HIGH) a switch. The difference is that using the Arduino means you don"t have the "bounce" problem. The hard part is that you have to code each HIGH and LOW of each line.

To simplify the steps, I"m going to use a table in which each HIGH is replaced by a 1, and a LOW is replaced by a 0. After each step, the EN (enable) line on the system has to be set HIGH, then LOW. This tells the LCD to read in the data or instructions.

If you happen to be using the normal LCD library for an Arduino, or programming the LCD using a C or C++ based system, then when you program it to, say, show the letter "H", or program it to have the cursor blink, then your programming has to be setting the various lines in a manner similar to what we just did above. Think of this as "assembly language for the LCD".

fortune is a program that displays a pseudorandom message from a database of quotations that first appeared in Version 7 Unix.BSD fortune, originally written by Ken Arnold.fortune cookies (hence the name), quotations from famous people, jokes, or poetry. As of November 2017, the quotations (with the exception of tips relevant to system operation) have been removed from FreeBSD entirely after user complaints regarding quotations from Adolf Hitler being contained in some of the files.

The original fortune program could be used for the more general task of picking up a random line from a plain-text file. The example of such use is given in the rc documentation. However, in most modern Unix systems fortune cannot be used this way, since they use an ad hoc file format for fortune files to allow multiline aphorisms.

Conventional versions of fortune use two files for each quotation list: a text file with quotations, each separated by the character "%" on its own line, and a random-access data file generated by the strfile(1) program. Alternative implementations, including those made for display on Web pages, typically use only the text file.

When I start my code, it displays as expected the initial screen on the LCD (as defined in setup() function) and then the temperature. But suddenly the LCD displays random characters, see attached, and somehow never stop displaying random characters until i restart the board.

We come across files and folders name very regularly. In most of the cases file/folder name are related to the content of the file/folder and starts with number and characters. Alpha-Numeric file name are pretty common and very widely used, but this is not the case when we have to deal with file/folder name that has special characters in them.