Instructions

ManualsBrandsJoy-it ManualsDevelopment Kits & EducationJoy-it RB-LCD-16x2 Module 5.6 cm (2.22 ") 16 x 2 p Compatible with: Raspberry Pi

Beginner’s Guide

to the

PI LCD

Part 1: Assembly

W8BH

1) INTRODUCTION

LCD Modules are a very common and inexpensive interface for microcontroller boards like

the Arduino. So why would you want to connect one to the Raspberry Pi, which has

advanced, high-resolution video display capability?

- Your HDMI display is hooked up to your other Raspberry Pi

- Your HDMI display is actually your TV, and someone is using it.

- You don’t have a video display device for your Pi.

- You want to learn about LCD modules.

- Because you can.

In this tutorial we will look at the handy LCD module sold at mypishop.com. It mounts on

top of your pi, and gives us four pushbutton switches in addition to a choice of LCD modules

to use.

2) ASSEMBLY

Building this small board is very straightforward. There are very few parts: four switches,

four resistors, a 26-pin female header, a row of male header pins, and the LCD. As always,

put them in some container on your workspace so they don’t walk away. I use a shoebox

lid.

There are no directions for the kit, so print out the online assembly instructions. All of the

parts, EXCEPT the 26-pin header, go on the printed side of the board.

Did you notice an adhesive-backed plastic disc in your kit? This disc provides physical and

electrical isolation between your add-on board and the Pi. It also provides for some

Summary of content (6 pages)

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Beginner’s Guide to the PI LCD Part 1: Assembly W8BH 1) INTRODUCTION LCD Modules are a very common and inexpensive interface for microcontroller boards like the Arduino. So why would you want to connect one to the Raspberry Pi, which has advanced, high-resolution video display capability? - Your HDMI display is hooked up to your other Raspberry Pi Your HDMI display is actually your TV, and someone is using it. You don’t have a video display device for your Pi. You want to learn about LCD modules.
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mechanical stability. Mount your board on the Pi and press down on it. The first thing my board hits is a tall electrolytic capacitor on the Pi. Put your adhesive disc at this spot. You can affix the disc to the bottom of the board or to the top of the capacitor. Either way, it prevents direct contact and minimizes board sagging. 16-pin female header Here is a photo of my board. I decided NOT to solder the LCD to the board. Instead I soldered a 16-pin female header.
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4) SMOKE TEST Your Pi should be turned off when your mount your board. Check all your solder joints. Then mount the board onto the Pi’s GPIO pins. Don’t be a dimwit like me and mount your display backwards -- it won’t work. The board mounts over the Pi, not away from it. Check to see that the connector is correctly seated on the pins, and turn on the power. The backlight on your LCD display should immediately light up, telling you that it has power. If not, immediately unplug and check everything again.
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Import the RPi.GPIO module. The first thing we’ll do is configure it to use the Broadcom port-numbering scheme. And we’ll turn off warnings about port usage: >>> import RPi.GPIO as GPIO >>> GPIO.setmode(GPIO.BCM) >>> GPIO.setwarnings(False) If python complains at the first statement, make sure that: 1) you have already installed RPi.GPIO; 2) you spelled it correctly, with a lower-case ‘i’; and 3) you started python from root.
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You can write each setup statement, or create a loop to do all four. Next, add a routine that checks each input and writes its value to the console: def CheckSwitch (): val1 = not GPIO.input(4) val2 = not GPIO.input(23) val3 = not GPIO.input(10) val4 = not GPIO.input(9) print val1,val2,val3,val4 I added the ‘not’ operation so that push-button presses show up as ‘True’, rather than ‘False’.
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) PYTHON SCRIPT for PI LCD, PART 1: ######################################################################## # # LCD1.py: Learning how to read GPIO inputs # # # # # ######################################################################## import time import RPi.GPIO as GPIO #INPUTS: map GPIO to Switches SW1 = 4 SW2 = 23 SW3 = 10 SW4 = 9 INPUTS = [SW1,SW2,SW3,SW4] #for timing delays #GPIO4 #GPIO16 #GPIO10 #GPIO9 = = = = Pi Pi Pi Pi pin pin pin pin 7 16 19 21 def InitIO(): GPIO.setmode(GPIO.BCM) GPIO.