This 7 inch display has a built-in battery and works with any HDMI device.

3D Printer Host control

While Octoprint running on a Raspberry Pi works excellent, occasionally we'll need to maintenance printer by updating the firmware. This when we need a full blown windows pc for uploading the files. 

So we built this project to easily control some of the printers we use.

We like this because it's actually a lot smaller to bring this over to a printer then it is to bring over a MacBook Air. So much smaller that we can fit the display right inside the printer and configure printers that can only use windows software.   

This design is an update to our previous 7 inch design. This time around we made the build easier to assemble by using snap fit nubs to hold the lid onto the case instead of screws. 

Attach a PC or Raspberry PI

Mounts are easy to add in the model or just make threads right on to the lid to attach your favorite tiny computer!

Rechargeable circuit

We used a PowerBoost 1000c to easily power the circuit, so its easy to recharge it from the USB port on the side. 

Tripod compatible 

We even included geometry on the case for adding a tripod compatible screw to make it easy to mount the entire enclosure to a tripod. The tripod screw fits flush against the enclosure so it can stand upright on its side when the tripod isn't needed. 

Interchangeable HDMI Connectors

We used these small interchangeable DIY HDMI Cable Parts - Right Angle (R bend) HDMI Plug Adapter connectors. They feature a latching mechanism to connect to flat flexible ribbon cables.

The connectors are available in different angle configurations, so it's easy to mix and match them based on the type of project. Think of them like lego for HDMI connections! 

Measure and Cut Wires

First we'll need to prepare the wires needed to connect the display to the PowerBoost. The PowerBoost will also need wires for the slide switch to turn the circuit on and off. We used 26 gauge silicone wires for the connections.

The + and - pins that connect to the display will need to be 240mm long.

The Enable and Ground pin will need to be 270mm long to reach the slide switch.

Solder wires

We can use a third helping hand to secure the PowerBoost while we tin and solder the wires to the pins.

Solder the + and - wire so they are pointing away from board as shown in the picture.

Solder the GND and EN pins with the wires angled straight up as shown in the picture.

Slide Switch

Solder the GND and EN wires to each of the two pins on the slide switch. We like to use heat shrink tube to insulate the connects. We can also trim off the unused pin. Just make sure not to cut the pin in the middle! 

Connect Display

Now we can solder the + and - wires to the display. The + wire will connect to the 5v+ pad and the - wire will connect to the GND pad on display backpack. 

Angle the wire so they are positioned to the center of the display as shown in the picture.

Plug in HDMI Connector

We can now plug in the HDMI connector into the display before we mount the screen into the case. We used the 90 Degree Up Angled HDMI Type A Male so the ribbon cable can plug in from the top.

Mount display

With the display soldered to each connection we can go ahead and insert it into the 3d printed case. Insert the display at an angle as shown in the gif. 

Once inside we can look at the tabs on the display backpack and then slide it over slightly to align it to the standoffs on the case.

Slide Switch

Arrange the wires on the slide switch and insert the switch into the port cutout on the middle portion of the case. Insert the switch at an angle as shown in the gif.

Mounting the PowerBoost

Now we can position the lid above the case as shown in the picture. We'll need to use four M2.5 x 5mm screws to secure the PowerBoost to the standoffs on the lid. Position the USB port on the PowerBoost so it faces away from the case.

Mounting the display

To secure the display to the standoffs inside the case, we'll need four M3 x 6mm screws. 

Position the display so the HDMI connector is on the same side of the port opening on the case. Now we can fasten the four screws to secure the display in place.

Mounting the battery

We can use gaffers tape to attach the lipo battery to the lid. Take note of were the mounting holes are located and position the battery in the middle of the four mounting holes.

Use a strip of gaffers tape and adhere it to the middle part of the battery and then tuck in both sides while attaching it to the lid part like shown in the picture.  

Closing the lid

Arrange the wires away from the sides of the case so we can safely snap fit the lid on top.

Before we completely snap the lid to the case, we'll need to slip the HDMI ribbon cable through the slit on the lid. Pull the ribbon cable through the slit as shown in the gif.

HDMI connector

Now we can connect the second HDMI connector to the ribbon cable. We used another 90 Degree Up Angled HDMI Type A Male connector. Lift the latch and then insert the ribbon cable to attach.

Brackets

The mini pc is held in place with two brackets that are secured onto the lid. We can use four M2 x 4mm screws to attach the brackets to the lid. First, fasten the screws to the lid to create threads for the screws. Now we can fasten the screws to the brackets and align them to the mounting holes on lid to attach the brackets.

Attach PC

Now we can slide in the mini pc. It should be a tight hold, but If the tolerances are too tight we can place the pc over the lid and then attach the brackets to the lid. 

And now we can easily pair the pc with any keyboard. We used the orange keyboard included with the Kano kit, but any wireless keyboard will work. 

We can easily update the design to include a Raspberry Pi by adding standoffs to the lid part in the Fusion360 file or just drill them right on the lid.