Cheap Miniature LCD Screen

At the Bristol Raspberry Jam in October 2012 I saw someone with a small 3.5 inch LCD attached to their Raspberry Pi. It cost less than £20 so I decided to buy myself one.

I had no idea what I was going to use it for but decided to worry about that another time.

What you get in the box

  • 3.5 inch TFT LCD screen
  • 2 female phono sockets for AV inputs (Yellow & White)
  • 1 male 5.5mm DC power jack with in-line fuse (Red)
  • 1 cable with female 5.5mm DC power plug on one end (Black)
LCD Screen and Cables

LCD Screen and Cables

LCD Screen Connectors

The screen accepts a composite video signal and is powered from 12V. You need to provide your own power supply and composite lead to connect to the Pi. I had both of these parts in my box of spare “stuff”. I used a 12V 2A power supply that came with an external hard drive as it had the correct power plug on it.

3.5 inch LCD Screen

Powering from 5V

The device is sold as a reversing camera screen for a car so it is not surprising that it is designed to be powered from 12V. In the world of the Raspberry Pi 5V is sometimes a more convenient voltage to be working and it is possible to modify/hack this device to run from 5V. This procedure is detailed in the RaspberryPi.org forum thread, Modifying a 3.5″ car display for USB power.

Making the console text larger

The text on the screen is very small and barely readable. This can be improved by increasing the font size of the console text. To do this run this command :

sudo dpkg-reconfigure console-setup

Then using the arrow and enter keys select the following options :

UTF-8

Guess optimal character set

VGA

16×28 (framebuffer only)

Wait a few seconds and the console text should change. It is now much easier to read on the 3.5 inch LCD screen.

3.5 inch LCD Screen with bigger font

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10 Responses to Cheap Miniature LCD Screen

  1. Looks great. I was worried that the text might be a bit small but you look to have overcome this. Definitely adding this to the TODO list. Rich

  2. sakuyaki says:

    Did you set values for sdtv_mode, adtv_aspect, overscan_disable, framebuffer_width, framsbuffer_height, overscan_left (right, top, bottom), and then comment all about HDMI setting in the config.txt ?

    I did,
    https://docs.google.com/open?id=0B0T91wB3ITStME1WYVFDN2JKYVE
    the 4.3 inch TFT-LCD has resoultion 480*272.

    How ablout your LXDE desktop ? What does it look like ?

    thanks,

    • david simpson says:

      what settings did you use pls to get the image so clear

      • Matt says:

        The first photo is just the screen plugged into the Pi with the default Raspbian image. The console-setup screenshots were taken using Putty on my Pc as they weren’t clear enough to follow on the 3.5inch screen itself. The last photo shows the increased font size due to the console-setup tweaks.

  3. Alex Johnstone says:

    That is nice…think I need one now!

    I can imagine having this showing weather, news, server stats, TV listings, a webpage, photos, notifications…all sorts

  4. Peter says:

    Got a link to the place you bought the screen from?

  5. Aj says:

    Is it possible to use this with the P5 header and 5v hack to power the pi and screen from one source or would I overload something? I have a handy 2.5a adapter around somewhere…

    • Matt says:

      The screen can draw 300-400mA and that might be a bit much to draw direct from the 5V pins. It’s probably better to power the screen direct from the power supply at the same time as the Pi. This might require a bit of creative wiring but it wouldn’t put an unnecessary load on the Pi.

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