How to use Displays with Raspberry Pi

Hey Guys, how are you going? I’m Sam from Core Electronics and today we’re going to be taking a look at using external displays with your Raspberry Pi.  Now the Raspberry Pi is capable of doing a lot of things, it can run scripts on Start Up, it can automate a lot of things but for most of the time you’re going to want to use it like you would a computer with a screen where you can see the desk top and the graphic user interface and see what’s going on. So we’re going to look at a couple of different ways you can connect up a display. Now the primary method of display for the Raspberry Pi is the HDMI Port. So HDMI is a standard of audio visual communication and it’s been around since the mid 2000’s and it’s got a plug that looks a bit like that and you should be familiar with it, it’s the standard for most TV’s,  Computers,  Monitors things like that and it carrys high definition video as well as two channel audio. Raspberry Pi can output both audio and video on the HDMI Port and it’s full size HDMI not mini HDMI. Now the  Raspberry Pi will work with that straight out of the box, there’s no configuration needed, no settings to change you simply get yourself a HDMI Cable Plug on one end, it doesn’t matter what into the HDMI Port on your Raspberry Pi and then you can connect that other end up to your TV, your computer monitor anything like that. The Raspberry Pi is going to work with any screen that has a HDMI Port. That is method 1.

As we’ve said there’s a couple of different ways we can do it and there’s also Composite Video. Now Composite Video is an older Analogue technology and we’ve got it in the form of this 3.5mm Jack. You might be familiar with Composite Audio and Video with the red, white and yellow plugs. The RCA Jacks that you would plug in to amplifiers and TV’s and other audio visual equipment but its been condensed down into a 3.5 mm 4 pole connector here. Now this looks like a standard headphone connector here and if you can see that there (02:00) and it’s the exact same shape and size except there’s 4 different tabs on there to connect to your cable and that allows for Ground, Audio Left, Audio Right and Video. So you can take that with one of our RCA to 3.5 mm cables that we’ve linked in to the article and connect that straight up and it will work with older TV’s and things like that but it’s not really a recommended method of connection because it only carrys standard definition video.  It has all of the limitations of that analogue technology.

We mentioned 4 ways, what are the other two? Well, we’ve got an LCD DSI connector on the bottom of the board there and it takes a 15 PIN Ribbon Cable. Now DSI stands for Display Serial Interface and it’s a method of displaying video data. Now there’s not a lot of screens that support this because it’s a lot more specific than an HDMI Port or Composite Video but the Raspberry Pi Foundation have released their official  7 inch Raspberry Pi Touch Screen which is awesome, its a really cool bit of gear. It’s designed so the Raspberry Pi Board itself just straps on to the back so I’ve got one set up here and we’ll take a look, it’s quite easy to set up. What we’ve got is this Ribbon Connector here and a USB Cable to get power to and from the Boards. So you connect a Micro USB Cable up to the Raspberry Pi Board to the Power Port and the other end of the USB Cable is a standard full size USB connector to the Control Board under there, if you can see under there there’s another Control Board.  This allows you to plug the Raspberry Pi power supply, the Micro USB one, there’s another USB Port underneath there, I don’t know how well you can see that, and it then feeds power to the Raspberry Pi Board as well itself. There’s no drivers required to use this guy, it’ll work straight out of the box and there’s four screws that you can mount the Raspberry Pi on the back and we’ve got it set up with a Pimaroni Case here, nice and simple and it allows you to have a self contained set up for your Raspberry Pi. Now the new build of Rasbian includes an on screen keyboard so you can do away with a keyboard and a mouse.  It’s a 10 Point  Capacitive Touch Screen so you can use the on screen keyboard as well as use mouse functions just by clicking on different things and there’s a whole  bunch of educational apps designed to take advantage of the touch interface which is cool, really cool bit of gear! But that is an example of how you use the LCD DSI Connector there, you just unhook those two tabs there and the cable will slide out quite easily and then you can, making sure those tabs are pulled out and you want to make sure the orientation of the cable is correct as to where the conductors are. Now slide it back in, you don’t ever have to force it and while it’s firmly seated in there  push those tabs down, not too hard, and that will lock the cable into place. That’s all there is to it, nothing fancy no configuration required with that, pretty cool.

The only configuration point of the three methods we’ve talked about is if you’re using composite video and/or audio you’re going to need to go in to the Config File and select that you’re using that as the output method because it will still go to the HDMI. That’s really easy, we’ve detailed the instructions for that in the article you can simply hold “SHIFT” when you’re starting up to go in to the NOOBS Manager or you can take the card and plug it into a SD Card Reader on a computer and you just write in that it’s sdtv_mode=2 and that sets it up for support for the PAL RCA Composite Video. There’s NTSC and depending on what region you’re in it might be a different mode but here in Australia we use PAL.

Then the last method, last of all, you might be wondering how many Ports are there on this thing! And that’s the GPIO pins themselves. The GPIO Pins have a wide variety of hardware peripherals available on them. You’ve got I2C, SPI, all of these extra hardware features that you can take advantage of. A lot of manufacturers have created HATs, HAT is the form factor of the the Raspberry Pi that supports direct connection to the Headers. Now it’s not technically a HAT all of the time because a HAT requires EEPROM and a device tree structure and all the rest but it takes advantage of the GPIO Pins and that’s really cool. You can get ones that are small, you know 2 - 3” touch screens or you can get Character Displays to output information from a script or program, different methods of displaying and that’s probably the most in-depth, it’s not super complicated but each manufacturer is going to have their own set of drivers or Python scripts or things that are going to configure the GPIO Pins to work how they’re required. It’s not hard but if you follow the instructions of the product that you purchase, be it Adafruit, SparkFun or Pimoroni they’ll have a link to where you can download that, and you just download all the drivers directly on to your Raspberry Pi.

That’s really all there is to it, connecting a display up to the Raspberry Pi is so easy, we’ve covered 4 different methods of how you can do it, HDMI, Composite Video and Audio as well, the LCD DSI Connector and also the GPIO Pins. That’s all for today guys, check out some of our other Raspberry Pi videos and get making :-)