question

Kevin Windrem avatar image
Kevin Windrem asked

Generic touchscreen on Cerbo

I just acquired a Cerbo GX and the companion Touch 50. I've been using a Waveshare HDMI touch screen on my Raspberry Pi running Venus. It communicated touch information via USB unlike the Touch 50.

As a test, I connected the Waveshare display to Cerbo. Works out of the box including touch. No overlays or any other software needed. No calibration necessary.

This might provide an alternative for those trying to locate the display a long way from Cerbo when the Touch 50 cable isn't long enough and an extender doesn't function.

The display I tried is this:

https://amazon.com/gp/product/B077PLVZCX

Others may also work

Note: you can NOT use the USB port closest to the HDMI connector as this is a power only port.

cerbo gxtouchscreen
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9 Answers
Jesse avatar image
Jesse answered ·

I can also confirm that the cheap ($50) 5" capacitive touch screens on AliExpress work perfectly with no configuration.

The 800x480 resolution and 5" size is more than enough. Less would be fine. I run touch data and power over the same USB 2.0 extension cable.

This is an example - EQV 5 inch Portable Monitor HDMI 800 x 480 Capacitive Touch Screen LCD Display for Raspberry Pi 4 3B+/ PC/Banana Pi|LCD Modules| - AliExpress

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liam-tuvey avatar image
liam-tuvey answered ·

Has anyone had any luck in turning off a third party (waveshare 7" HDMI in my case) screen automatically when connected to a Cerbo? Screen displays perfectly but auto time out and dimming functions within Venus dont take effect.

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Kevin Windrem avatar image
Kevin Windrem answered ·

I have one of the Waveshare 7" HDMI displays and screen saver works, but no dimming.

My RpiDisplaySetup will handle the necessary steps,

https://github.com/kwindrem/RpiDisplaySetup

or you can manually do it from the command line:

echo "/sys/class/graphics/fb0/blank" > /etc/venus/blank_display_device

Add the following line to /u-boot/config.txt:

hdmi_blanking=1


then reboot.

If you are plugged into the second HDMI port use fb1 in place of fb0.

If you do it manually, you'll need to repeat the steps after a firmware update.

If the display does not support backlight control, you will get a blank screen with the backlight still on.

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liam-tuvey avatar image
liam-tuvey answered ·

Thanks @Kevin Windrem, I'm actually trying to do this on a Cerbo GX not a Pi.
I attempted to use your script but it checks to see if it's running on a Pi and if not aborts.

I tried the first manual command as you suggested but didnt have any luck as I assume this is Pi specific. (also there is no /u-boot on the Cerbo)

I've looked at other solutions like /usr/bin/tvservice etc for turning off the screen but I'm wary of installing new services on Venus, seems to me to be preferable to use the existing functionality in Venus (if possible!)

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John macrae avatar image
John macrae answered ·

Thanks @Kevin Windrem , I'm also using a generic Aliexpress screen - works great! I bought one with a separate backlight button on the back. Fairly trivial to move it round the front - adjusts in 20% increments.

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Do you have a link to the product (from Aliexpress)?
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itsme avatar image
itsme answered ·

Just for information, if other user have the same problems like i had...

To use the Waveshare 7inch Screen (1024x600) you have to add the following to /u-boot/config.txt:

Section [all]

max_usb_current=1
hdmi_group=2
hdmi_mode=87
hdmi_cvt 1024 600 60 6 0 0 0
hdmi_drive=1

works perfect for me on a RPi 3+


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gmelton2 avatar image
gmelton2 answered ·

Kevin,

I know this is an old post but I have received two defective Touch 70 displays so I am looking for an alternative while Victron works out the issues with the Touch 70. I purchased the display that you linked from Amazon.

Disclaimer: I am electrical challenged but I am an engineer.

I connected the Waveshare display to the Cerbo and I am unsuccessful and making it functional. I connected the HDMI cable, of course. And I connected the included adapter from the USB connector on the Cerbo to the “DC” labeled port on the Waveshare. What am I missing?

TIA,

Greg

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Kevin Windrem avatar image
Kevin Windrem answered ·

To get touch to work you need to connect the TOUCH port to a USB port on Cerbo. The USB port closest to the HDMI connector is power only, so you need to pick another port. You should not need to connect the DC port as power is also supplied via the TOUCH port.

If you don't have enough USB ports on Cerbo, use a powered hub to connect everything.

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m-adriaans avatar image
m-adriaans answered ·

Hello,

I have connected a 7" UCtronics touchs screen to my Cerbo GX. All data is displayed correctly but the touch function needs calibration and I have no clue if that is possible and if so, how to do that. Any help is much appreciated.

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