Print with no supports, solid infill, 0.15 mm layer height. I used eSun PLA+. I tried to size the screw holes so that, in a pinch, you could just force the screws in. However, it is better if you can run an M3 tap though them first. Alternatively, you could probably drill them out and use threaded inserts. Note that you may need to bend the IR receiver on the board back in order to clear the wall. Be sure to use a bit of foam or hot glue to keep the SBM-20 from moving around. Since space is tight, things need to go together in a certain order. 1. Install tube, switches, bottom TRRS jack, and LCD 2. Install main board, being careful to line up the header pins on the LCD with the sockets on the board 3. Install the pushbutton and upper TRRS jack Power from the data/power jack is run through the power SPDT power switch. Thus, the power switch actually selects between the internal battery and external power, when present. The jack is wired specifically to keep the power from doing bad things to the data lines during live insertion. T - Tx R - Rx R - GND S - +5V The second 3.5 mm jack can be used for headphones. You will probably want to use some sort of inline analog volume control to save your ears. Parts 3x M3 x 12mm flathead screws (I used black hex type because they look cool) 4x M3 x 10mm flathead screws (Phillips is nice here, because you have to remove them to change the battery) 2x Tensility 50-00082 3.5mm TRRS jack 2x E-Switch 100SP1T1B1M1QEH micro toggle switch 1x C&K 8125SHZBE pushbutton (With clicky tactile feedback!) PL2303HX UART adapter and 3.5mm TRRS cable (ebay)