3.5" gpio LCD setup guide

[eriknz]

Here's some instructions that would have helped me set up openrowingmonitor on my Raspberry Pi 3B with a 3.5" MPI3501 gpio lcd screen:

Using Raspberry Pi Imager:
For the operating system choose "Raspberry Pi OS (other)" -> "Raspberry Pi OS (Legacy, 64-bit) Lite".
For OS customisation settings, leave the username as "pi" because the openrowingmonitor install script expects it.
Set hostname as "rowingmonitor".
Configure wireless LAN so the pi can connect to your wifi and so you can access it with PuTTY. And on the Services tab, enable SSH.

With the sdcard in the pi and it powered on, you should be able to connect to it with PuTTY if you set the Host Name to rowingmonitor.local but it might take a few minutes before it'll work.

After connecting and logging in with PuTTY, run the install script:

sudo /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/jaapvanekris/openrowingmonitor/HEAD/install/install.sh)"

reboot takes a while the first time after the script.

Check the samba share is working before proceeding, you might need to run the script again.

In windows explorer, you should be able to access the samba share by typing "\\rowingmonitor.local" in the address bar. In the Configuration folder, you can edit config.js in Notepad, add "gpioPin: 26," on the line above the final '}'. This is because the screen uses gpio 17.
Alternatively, you could edit the file via PuTTY:

sudo nano /opt/openrowingmonitor/config/config.js

Also edit /boot/firmware/config.txt, change gpio=17=pu,ip to gpio=26=pu,ip:

sudo nano /boot/firmware/config.txt

The following instructions are mostly from https://www.reddit.com/r/raspberry_pi/comments/1bnav0y/i_finally_have_the_35inch_gpio_spi_lcd_working/

1. fresh install of RPI OS bookworm (Expand file system -> reboot -> and then run sudo rpi-update)

sudo raspi-config

Advanced -> change wayland to X11

Interface-> SPI - enable

3. in the terminal type

sudo nano /boot/firmware/config.txt

Add a "#" in front of the line "dtoverlay=vc4-kms-v3d"

add this line at the end of the file " dtoverlay=piscreen,speed=18000000,drm,rotate=0 "

(remove the double inverted commas "")
you can edit rotate=0 to 180 etc to change screen orientation.

4. Reboot

be very patient (takes ages). At this point the screen should work but not the touch screen. I was impatient and connected via SSH, just after I did that the screen started working, showing openrowingmonitor. I'm not sure if logging in triggered it to work.

sudo apt-get install xserver-xorg-input-evdev

sudo mv /usr/share/X11/xorg.conf.d/10-evdev.conf /usr/share/X11/xorg.conf.d/45-evdev.conf

sudo nano /usr/share/X11/xorg.conf.d/45-evdev.conf

Add these lines at the end of the file

Section "InputClass"
        Identifier "evdev touchscreen catchall"
        MatchIsTouchscreen "on"
        MatchDevicePath "/dev/input/event*"
        Driver "evdev"
        Option "InvertX" "false"
        Option "InvertY" "true"
EndSection

NOTE: if the touch input is still not working correctly , then play around with Option "InvertX" "false", Option "InvertY" "true" in the step 7 untill you get the desired result.

sudo reboot

sudo touch /etc/X11/xorg.conf.d/99-calibration.conf

sudo apt-get install xinput-calibrator

sudo reboot

12. type this in the terminal :

DISPLAY=:0.0 xinput_calibrator

Calibration software will run and will be visible on the screen, press the 4 markers to calibrate and the touch would become pretty accurate.

One last note, don't be tempted to try setting up chromium as a web kiosk unless you know what you're doing (it's reported to work worse anyway).

[JaapvanEkris]

Thanks for reporting back. I am considering writing a LCD screen setup guide for ORM, and this is a pretty good start!

[Paku1964]

Thanks for the guiding on the username, that needs to be pi. I have no experience on this, and this help me to be able to get system running.
My acknowledgement to all contributors that did this possible.

[gerokleindienst]

@Paku1964 Thank you for this good explanation to make the 3,5" display running. I got it working. But you are right: it takes ages for the system to start.. After some tries I got even the calibration right, although DISPLAY=:0.0 xinput_calibrator did not lead to success. But when using the recommended parameters of the manufacturer, it worked.

But I have an essential question. In my case, the display-head uses the Pins 1-26 of the Raspberry Pinout, so that I can connect SIG to GPI0 26 on Pin 37 and GND to Pin 39. But where can I get 3,3 V from? Or do you have flexible connections to the pins that are mandatory to run the display?

[Paku1964]

I have a Pi 4 and the 5 " display, power supply for display is 2 and 6 or 4 and 6, I use for hall sensor 3,3 V from pin 1