Step #3

1. RetroPi working on a Raspberry Pi just connected to a monitor.

I followed these instructions. I used the pre-build Raspberry Pi image for a 3B+.

2. 4" HDMI screen working with RetroPi.

Because I loaded the RetroPi image, there is no "PIXEL" desktop GUI. I therefore had to press "F4" to get to the terminal and do all the commands there to load the driver.

First I needed to turn on SSH, so that if (when) the screen goes blank but I still need to change some parameters, I can remotely log into the Pi. You also need to connect to the wifi, so that you can download the drivers.

I got the instructions from here.

• map keyboard as controller

• connect to wifi under configuration in RetroPie

• press F4 to exit to the terminal

• mkdir waveshare

• cd waveshare

• wget http://www.waveshare.com/w/upload/0/00/LCD-show-170703.tar.gz

• tar xvf LCD-show-170703.tar.gz

• cd LCD-show-170703

• chmod +x LCD-4show

• ./LCD-4show

• then add the following lines to config.txt:

• hdmi_group=2

hdmi_mode=87

hdmi_cvt 480 800 60 6 0 0 0

dtoverlay=ads7846,cs=1,penirq=25,penirq_pull=2,speed=50000,keep_vref_on=0,swapxy=0,pmax=255,xohms=150,xmin=200,xmax=3900,ymin=200,ymax=3900

display_rotate=3

• then do:

• cd LCD-show/

./LCD4-800x480-show 180

• disconnect the regular HDMI screen and attach the 4" one and reboot Pi and the screen should work

3. Picade working

I had to load the driver for the Picade HAT.

• https://github.com/pimoroni/picade-hat

• I used the 1 line installation:

  • curl -sS https://get.pimoroni.com/picadehat | bash

I then wired up a push button on a breadboard to see if RetroPi would recognize the "A" button input. It does.

This site also helped:

• https://learn.pimoroni.com/tutorial/sandyj/assembling-your-picade

• https://learn.pimoroni.com/tutorial/sandyj/getting-started-with-picade-hat

4. Picade sound and "soft" on/off switch

The main reason for using the HAT is not the buttons (I could do that with GPIO pins) but for the build in speaker and "soft" on/off.

The problem is the speaker driver was only mono and I wanted 2 speakers. You can not just "double" connect them, since you will have the wrong resistance (ohms). I found this solution and it worked great.

The soft on/off also works, only once the Picade drive is loaded for off. There is a program running in the background checking for it.

• https://forums.pimoroni.com/t/picade-hat-speakers-and-power-button-questions/5070/2

• https://forums.pimoroni.com/t/picade-hat-volume-control/3720/3

• (I can not get the volume buttons working?)

5. Power Boost 100

I wanted this because it not only recharges the LIPO battery (3.7 V), it also is a voltage regulator for the Pi. Once all wired up, no problem at all. It provides a nice 5.1 V and recharges 3.7 to 4.2 V batteries.

6. 3D parts

I did some test prints and yes it should work. I just have to figure out the best placement of items, so that it is not too thick.

7. Perfboard buttons work inside case

I had never used 3D printed buttons hitting push buttons, so I need to prove that it would work.

9. Make Linux terminal text bigger

Since the screen is so small, I want to make the terminal text larger so that I can see it better:

• https://www.raspberrypi-spy.co.uk/2014/04/how-to-change-the-command-line-font-size/

10. Change the Emulator theme to:

• snes-min

11. Change the load splash screen to:

• get new splash screens

• then pick: edmaul169-playschoice-10.png

• https://github.com/RetroPie/RetroPie-Setup/wiki/splashscreen

12. Remove the run command option when a game loads:

• https://github.com/retropie/retropie-setup/wiki/runcommand