In this part of the build, I start fitting everything in the case. Some of the parts required serious modification to get everything to fit. It was slightly nerve-wracking at times, but I pushed forward, confident after the extensive testing performed in the previous sections.
Screen and RPi Board Fitting
The 2.8" PiTFT screen was too wide to fit in the case. I knew this when ordering it and was just lucky there was a side of the PCB with nothing important on it that I could trim down. I used a cutting wheel on my dremel to trim of 1-2mm from the side opposite of the connector. This was enough to get it to fit snuggly in the case. Following that, I removed the top-most screw posts with a burr and was able to fit both the RPi board and screen in the case, at least partially.
I had been putting it off until this point, but I finally trimmed back the battery compartment as well. The RPi board extended enough that it would just reach into this area. Again, I tried to be conservative with what I removed because the battery compartment is a pretty vital part of the structure. After finishing the build, I realized I could have removed less, but I haven't noticed any issue because of it.
Screen and GPIO Cable
Originally, I bought both the 40-pin and 26-pin cables from Adafruit.com. This turned out to be a good decision as I ended up splicing the connectors together, leaving a 26-pin connector one end with 14 free wires and a 40-pin connector on the other. As another stroke of luck, the 2.8" PiTFT screen has two connectors on the back, one male and one female. The male connector is vertically aligned and with a trimmed back ribbon cable it was perfectly aligned for the RPi board to be mounted portrait style and the screen mounted in a landscape orientation. I did cut the first cable too short and the second one too long.
Desoldering USB and Network Ports
It was really important to have all the software and everything else in place at this point as I would be depending on the Wifi for a network connection and be unable to connect a keyboard if there was an issue. It was probably the most nerve-wracking portion of the build. Desoldering components from a board is never fun and I was a little worried about over-heating the board and burning something out. Obviously, it all worked out in the end, but it was time consuming and is a pretty good argument for using a Pi Zero if you can get your hands on one. I tried a couple of tricks to get the ports to come out easily, but I don't own a re-work station to really take the effort out of it. What ended up working the best was trimming the excess leads on the components, then globbing on a bunch of excess solder. Then it was just a matter of yanking on the port with pliers while constantly moving the iron around on the pins.
Replacing a USB Connection
I had thought about cutting down micro USB connectors for both the Pro Micro and power, but only ended up doing it for the Pro Micro. The connector for power would have stuck out too far and I don't have any right-connectors on hand. For the Pro Micro, I just cut off one end, stripped all of the insulation and soldered it directly to the RPi board, making a direct plug-in cable for it. Looking back, I should have soldered it on at the right-side port instead of the middle as it kind of interfered with the battery later. It was nice, however that I was able to unplug the gamepad and screen while I still working everything out.
Hardwiring Power
I tacked on leads to the bottom of the RPi board to provide power directly. During testing I still used the micro USB plug until the final assembly when I patched it into the Power Boost board. Helpfully, the RPi designers have included a number of test points on the bottom of the board that are very easy to solder to.
Gamepad Wiring
I soldered some rainbow ribbon cable to the gamepad PCB and then connected it to the I/O pins on the Pro Micro. The rainbow colors were useful for tracing which pad corresponded to which pin, but overall was kind of annoying to work with because the wires were so thin. I opted to leave the left and right trigger buttons disconnected until final assembly as they will be later installed in the back of the case. This was useful during the build as I was able to keep the front and back detached from each other while still working on it. I did have to reprogram the pin out code in the Pro Micro because I wired the pins differently from the original testing and development.
The 2.8" PiTFT screen was too wide to fit in the case. I knew this when ordering it and was just lucky there was a side of the PCB with nothing important on it that I could trim down. I used a cutting wheel on my dremel to trim of 1-2mm from the side opposite of the connector. This was enough to get it to fit snuggly in the case. Following that, I removed the top-most screw posts with a burr and was able to fit both the RPi board and screen in the case, at least partially.
I had been putting it off until this point, but I finally trimmed back the battery compartment as well. The RPi board extended enough that it would just reach into this area. Again, I tried to be conservative with what I removed because the battery compartment is a pretty vital part of the structure. After finishing the build, I realized I could have removed less, but I haven't noticed any issue because of it.
Originally, I bought both the 40-pin and 26-pin cables from Adafruit.com. This turned out to be a good decision as I ended up splicing the connectors together, leaving a 26-pin connector one end with 14 free wires and a 40-pin connector on the other. As another stroke of luck, the 2.8" PiTFT screen has two connectors on the back, one male and one female. The male connector is vertically aligned and with a trimmed back ribbon cable it was perfectly aligned for the RPi board to be mounted portrait style and the screen mounted in a landscape orientation. I did cut the first cable too short and the second one too long.
It was really important to have all the software and everything else in place at this point as I would be depending on the Wifi for a network connection and be unable to connect a keyboard if there was an issue. It was probably the most nerve-wracking portion of the build. Desoldering components from a board is never fun and I was a little worried about over-heating the board and burning something out. Obviously, it all worked out in the end, but it was time consuming and is a pretty good argument for using a Pi Zero if you can get your hands on one. I tried a couple of tricks to get the ports to come out easily, but I don't own a re-work station to really take the effort out of it. What ended up working the best was trimming the excess leads on the components, then globbing on a bunch of excess solder. Then it was just a matter of yanking on the port with pliers while constantly moving the iron around on the pins.
I had thought about cutting down micro USB connectors for both the Pro Micro and power, but only ended up doing it for the Pro Micro. The connector for power would have stuck out too far and I don't have any right-connectors on hand. For the Pro Micro, I just cut off one end, stripped all of the insulation and soldered it directly to the RPi board, making a direct plug-in cable for it. Looking back, I should have soldered it on at the right-side port instead of the middle as it kind of interfered with the battery later. It was nice, however that I was able to unplug the gamepad and screen while I still working everything out.
I tacked on leads to the bottom of the RPi board to provide power directly. During testing I still used the micro USB plug until the final assembly when I patched it into the Power Boost board. Helpfully, the RPi designers have included a number of test points on the bottom of the board that are very easy to solder to.
I soldered some rainbow ribbon cable to the gamepad PCB and then connected it to the I/O pins on the Pro Micro. The rainbow colors were useful for tracing which pad corresponded to which pin, but overall was kind of annoying to work with because the wires were so thin. I opted to leave the left and right trigger buttons disconnected until final assembly as they will be later installed in the back of the case. This was useful during the build as I was able to keep the front and back detached from each other while still working on it. I did have to reprogram the pin out code in the Pro Micro because I wired the pins differently from the original testing and development.
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