adafruit lcd display raspberry pi quotation

This new Adafruit Pi plate makes it easy to use a blue and white 16x2 character LCD . Unfortunately, these LCDs do require quite a few digital pins. 6 to control the LCD and then another 1 to control the backlight for a total of 7 pins. That"s nearly all the GPIO available on a Pi. With this in mind, we wanted to make it easier for people to get these LCD into their projects so Adafruit devised a Pi plate that lets you control a 16x2 character LCD, up to 3 backlight pins & 5 keypad pins using only the two I2C pins on the R-Pi. The best part is you don"t really lose those two pins either, since you can stick i2c-based sensors, RTCs, etc. and have them share the i2c bus. This is a super slick way to add a display without all the wiring hassle.

WARNING: If you"re using the new Raspberry Pi model B+ with 4 USB ports you will need to take some extra steps to ensure the backlight resistor elads do not touch the USB ports and short out. Refer to Assembly link at resources, below, for more details.

The Snake Eyes Bonnet is a Raspberry Pi accessory for driving two 128x128 pixel OLED or TFT LCD displays, and also provides four analog inputs for sensors. It"s perfect for making cosplay masks, props, spooky sculptures for halloween, animatronics, robots...anything where you want to add a pair of animated eyes!

Connecting an LCD display to your Raspberry Pi is sure to take any project up a notch. They’re great for displaying sensor readings, songs or internet radio stations, and stuff from the web like tweets and stock quotes. Whatever you choose to display, LCDs are a simple and inexpensive way to do it.

In this tutorial, I’ll show you two different ways to connect an LCD to the Raspberry Pi with the GPIO pins. The first way I’ll show you is in 8 bit mode, which uses 10 GPIO pins. Then I’ll show you how to connect it in 4 bit mode, and that uses only 6 pins. After we get the LCD hooked up I’ll show you how to program it with C, using Gordon Henderson’s WiringPi LCD library.

I’ll show you how to print text to the display, clear the screen, position the text, and control the cursor. You’ll also see how to scroll text, create custom characters, print data from a sensor, and print the date, time and IP address of your Pi.

There’s another way to connect your LCD that uses only two wires, called I2C. To see how to do that, check out our tutorial How to Set Up an I2C LCD on the Raspberry Pi.

Most people probably want to connect their LCD in 4 bit mode since it uses less wires. But in case you’re interested, I’ll show you how to connect it in 8 bit mode as well.

In 8 bit mode, each command or character is sent to the LCD as a single byte (8 bits) of data. The byte travels in parallel over 8 data wires, with each bit travelling through it’s own wire. 8 bit mode has twice the bandwidth as 4 bit mode, which in theory translates to higher data transfer speed. The main downside to 8 bit mode is that it uses up a lot of GPIO pins.

In 4 bit mode, each byte of data is sent to the LCD in two sets of 4 bits, one after the other, in what are known as the upper bits and lower bits. Although 8 bit mode transfers data about twice as fast as 4 bit mode, it takes a longer time for the LCD driver to process each byte than it takes to transmit the byte. So in reality, there isn’t really a noticeable difference in speed between 4 bit mode and 8 bit mode.

If you’ve never worked with C programs on the Raspberry Pi, you may want to read our article How to Write and Run a C Program on the Raspberry Pi first. It will explain how to write, compile, and run C programs.

WiringPi is a C module that makes it easy to program the LCD. If you already have WiringPi installed on your Pi, you can skip this section. If not, follow the steps below to install it:

WiringPi has it’s own pin numbering system that’s different from the Broadcom (BCM) and RPi physical (BOARD) pin numbering systems. All of the programs below use the WiringPi pin numbers.

To use different pins to connect the LCD, change the pin numbers defined in lines 5 to 14. You’ll need to convert the WiringPi pin numbers to the physical pin numbers of the Raspberry Pi. See here for a diagram you can use to convert between the different numbering systems.

To use the LCD in 4 bit mode, we need to set the bit mode number to 4 in the initialization function (line 20 below). The following code prints “Hello, world!” to the screen in 4 bit mode:

By default, text is printed to the screen at the top row, second column. To change the position, use lcdPosition(lcd, COLUMN, ROW). On a 16×2 LCD, the rows are numbered from 0 to 1, and the columns are numbered from 0 to 15.

The function lcdClear(lcd) clears the screen and sets the cursor position at the top row, first column. This program prints “This is how you” for two seconds, clears the screen, then prints “clear the screen” for another two seconds:

Each LCD character is a 5×8 array of pixels. You can create any pattern you want and display it on the LCD as a custom character. Up to 8 custom characters can be stored in the LCD memory at a time. This website has a nice visual way to generate the bit array used to define custom characters.

To print a single custom character, first define the character. For an example of this see lines 12 to 19 below. Then use the function lcdCharDef(lcd, 2, omega) to store the character in the LCD’s memory. The number 2 in this example is one of the 8 locations in the LCD’s character memory. The 8 locations are numbered 0-7. Then, print the character to the display with lcdPutchar(lcd, 2), where the number 2 is the character stored in memory location 2.

Here’s an example of using multiple custom characters that prints the Greek letters omega, pi, and mu, plus thermometer and water drop symbols for temperature and humidity:

As an example to show you how to display readings from a sensor, this program prints temperature and humidity readings to the LCD using a DHT11 temperature and humidity sensor. To see how to set up the DHT11 on the Raspberry Pi, see our article How to Set Up the DHT11 Humidity Sensor on the Raspberry Pi.

Hopefully this helped you get your LCD up and running on your Raspberry Pi. The programs above are just basic examples, so try combining them to create interesting effects and animations.

If you have any problems or questions about installing the LCD or programming it, just leave a comment below. And don’t forget to subscribe to get an email when we publish new articles. Talk to you next time!

first of all let me say that I dont have any experience with a Raspberry, Arduino etc. at all, and also dont own any equipment yet. This is more a general question to the more experienced members here, so please bear with me if this comes across as a big unfocused

What I would like to do is built a keystand for my girlfriend in a NES case, that includes a function to display random quotes in the cardridge slot on key press. Basically, everytime she leaves the house in the morning she can press a button and a nice random quote from storage will be displayed on a LED. Thats it!

I have read through a lot of post here and other forums, and I found things similar to this (I found a post about random fortune cookie quotes), but those were all a bit more focused on the coding in itself, which is not really accessible to me (i have only very basic programming knowledge, and I am not sure if I have time to learn the basics fully). I am trying to catch up on everything myself, but thought that asking my be helpful. So I just wanted to ask for opinions on the following things:

3) Is there are generally very well regarded resource for such tutorials? I have started reading the "Beginning with Raspberry Thread" here, but just in case I thought it might be good to ask.