• Adafruit 7" LCD backplate, with raspi slot

    Audrey Robinel02/11/2015 at 07:52 0 comments

    I finished designing the backplate for the 7" LCD from adafruit. It has ears to secure it to the rest of the system. I added reinforcement to make it stiffer, and a cutout for the cable ribbon.

    There are standoffs for the LCD's electronic circuit, and standoffs to secure a Raspberry Pi, model A+ or B+.

    Here is a rendering of this part :

    The green block on the left is the LCD driver, and the lighter green block on the right is a Raspberry pi B+. The blue block beneath is the LCD.

    The 6 fixation ears have 3mm holes, to secure it on another part. The plan is to have a border around the LCD on this other part, so it can't move laterally. Then this plate screws onto it, locking it on a vertical axis, causing it to be fixed. Had the LCD had mounting tabs, i would have been able to make a simpler design. But here it is, and i'll print one tomorrow.

    I'll design a complementary part in order to enclose this screen so that it can be used on it's own. I'll also design a thicker part to also enclose the raspberry opi, and then multiple parts for the console.

  • Screen electronics management

    Audrey Robinel02/11/2015 at 05:48 0 comments

    The two LCD's that i'm using for testing purposes are made of the LCD itself, and one or more electronic cards to drive it. The 7" LCD has an HDMI driver, whereas the 5" LCD has the HDMI driver, a touchscreen controller and a small flexible circuitry.

    On the 5" LCD, i managed to organize everything with duct tape (and double face one).

    For the 7", i can't obtain good results this way. For that purpose, i have begun designing a backplate to hold the circuit in place.

    I measured the PCB and made a support, with holes for screws :

    It worked properly, i printed one and taped it to the back of the screen with success. However, this was a first step. Now, i'm designing a full backplate, with a fixation for the raspberry pi too, and i will add something on the edge to secure the screen on a frame that i'll design.

    By the way, this is the 7" screen i'm using :

    https://www.adafruit.com/products/1933. For the same price, they sell this one : https://www.adafruit.com/products/2300. It seems identical, except that it has an higher resolution of 1024*600 rather than 800*480. I wonder why i took the first rather than the second.

    The 5" screen is a tactile one :


    It's more expensive, but i wanted to have a tactile screen for some potential uses. Now i'm not so sure about it. It works, but it's not that useful in this project. I wanted to use it on tactile games, but i wonder if i'll use any on this system. However, the tactile layer leaves the possibility to use various kinds of graphic interfaces.