#Startx not working raspberry pi code

×1 Raspberry Pi, any model, with monitor, mouse and keyboard.Can you connect more wires and have one Raspberry Pi wired up to two or three jelly babies at the same time, playing different notes?įor Tutors Equipment – for each workstation See if you and your classmates can play a tune such as Mary Had A Little Lamb (EDCDEEE,DDD,EEE,EDCDEEE,EDDEDC).įind a list of GPIO pins ( ). Try changing your program to use a different note.

There are also scream sound files for the notes D and E. Your program plays a scream for the musical note C. Problems listening to this file? See media help. Save the program, then run it by starting LXTerminal from the desktop (double-click) then enter: Time.sleep(1) means to wait for 1 second. Two equals signs are used to compare one thing with another. One equals sign is used to set a value, such as a=3 means that every time the computer sees a it will know it has the value 3. The question being asked is whether the two wires are touching is pin 3 connected to the electrical ground? Connecting an input pin to ground results in the value False. True tells the computer to always do something. While tells us to repeat a block of code. The os library lets us call other programs, such as the music player, but we’re not using that just yet.

The GPIO library lets us use the GPIO pins. The time library lets us tell the computer to wait ( sleep). These little programs are called libraries. The import lines allow us to use other people's little programs inside our program. We're using four spaces to indent each block some programmers prefer two or another number.

#Startx not working raspberry pi code

Blocks of code can be repeated, or the program can decide to run or miss out a block. You need to press the spacebar to make sure they line up. The spaces under the while and if lines are also important. You need to make sure that everything in capitals really is in capitals, and everything in lowercase really is in lowercase. sleep ( 1 )Īll the capitals really matter. input ( 3 ) = False : print 'Ouch!' time. IN ) print 'Hello World' while True : if GPIO. Import time import RPi.GPIO as GPIO import os GPIO. Start IDLE from the desktop (double-click), the load your old program by going to File menu, Recent Files and selecting jellybaby.py. Put the power lead back in, wait for the Raspberry Pi to turn on, then log in ( pi / raspberry don't forget startx if your desktop doesn't start automatically). It’s easy to make a mistake identifying pin 25, especially on the 'Plus' models of Raspberry Pi which have 40 pins! It’s a lot less hard on the old Model B and Model A which only have 26 pins – pin 25 is the one at the end on the right. You will need to count in 2s starting from 1 on the left, so the count goes 1, 3, 5, 7 and so on. Even numbers are on the edge of the board and odd numbers are on the other row. Now attach the other ends of the jumper cables to pin 3 and pin 25 of the Raspberry PI's GPIO pins. Your tutor may have already put them in for you, or you might ask your tutor for some pliers to help push them in.

Larger paperclips may be difficult to fit. Take a female-to-female jumper cable and push the unwound paper clip in one end.ĭo this twice, so you have two wires, both with an unwound paper clip in the end. Unwind a metal paper clip so that it is a long straight-ish wire. Wait for the Raspberry Pi to turn itself off, then unplug the power cable. –h means halt (as opposed to –r which means restart) and now means, well, right now! (if there were other people using your Pi over the network, you could say +5 instead of now, to give a five-minute warning). You can either use the red power icon in the bottom-right corner of the desktop, or in the LXTerminal window (the black window) type: Make sure you tell the Raspberry Pi to shut down safely before you unplug the power. You should always turn off your Raspberry Pi before attaching wires to it. If you get it wrong, you can permanently damage your Raspberry Pi. Please check and check again that you’ve plugged into the right pins. jellybaby.py is the name of your program. Python tells the computer to run a program written in the python programming language. Since the Raspberry Pi is a very cheap computer, that doesn’t matter too much, but on other expensive computers you might want to be more careful with sudo. On the downside, running a program as a superuser allows you to do things which can break the computer – the superuser is like a superhero who can do anything. For many programs this doesn’t matter, but in a minute we are going to use electronics attached to the Raspberry Pi’s GPIO ports (General Purpose Input and Output), and you need to be the superuser to do that. Let’s have a quick look at what we did there: