JeVois  1.20
JeVois Smart Embedded Machine Vision Toolkit
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JeVois-Pro Quickstart user guide


For more details and step-by-step instructions, see the different sections under User guide

New users, be sure to check out JeVois Start.

  • Your HDMI display must support at least 1080p/60Hz (1920x1080 at 60 frames/s). If your computer monitor does not work, try your HD or 4K television.
  • Standard USB keyboards and mice should be detected automatically. Please try the most generic ones you have, if your fancy ones are not detected.
  • To insert the microSD card into JeVois-Pro, see JeVois-Pro: Introduction for new users
  • To connect JeVois-Pro see Connecting JeVois-Pro to Power and Data


  • I see the JeVois-Pro boot logo, but after that my monitor goes blank, or reports that picture is out of range. Your monitor needs to support at least 1080p (1920x1080). In some early shipments, we had set the resolution to 1080p30Hz, but it turns out that 1080p60Hz is more widely supported. Please try this fix:
    • carefully eject the microSD card from JeVois-Pro, as shown in this video
    • attach it to a computer using a card reader
    • open the drive called BOOT
    • in there, find file env.txt and open it using a plain text editor (e.g., Notepad, TextEdit, nano, etc). Just double-clicking on it should do the trick.
    • scroll down to the line that says: hdmi=1080p30hz and replace 30 by 60
    • save the file and cleanly eject the disk
    • insert the microSD back into JeVois-Pro and it should work.
  • The top and bottom of the video are clipped. Many televisions indeed crop the picture slightly by default. You need to go through the menus of your television and find a picture setting for "full native", "full resolution", "full 100%", etc. Here is an example with a Sceptre 4K TV:

Above: in normal mode on this TV, the picture is cropped slightly (see the line of text at the bottom of the screen). Click on picture to enlarge.

Above: Using the TV's remote to set the TV to "full 100%" eliminates the cropping. Click on picture to enlarge.

Boot modes

Under the System tab of the GUI, you can select different boot modes for JeVois-Pro:

  • JeVois: starts the JeVois software on boot.
  • Ubuntu console: starts a text console on boot.
  • Ubuntu graphical: starts X-Windows and provides a graphical login.

Once you are in either console or graphical mode, issue these commands in a terminal to switch:

sudo systemctl set-default # to boot to JeVois software
sudo systemctl set-default # to boot to Ubuntu console
sudo systemctl set-default # to boot to Ubuntu graphical


sudo shutdown -h now

Unplug power and plug it back in.

Software reset (shutdown -r) currently does not work. It is likely a hardware issue but we may be able to create a software workaround later.


User jevois has password jevois and is capable of sudo (using that password).

User root has password jevois

JeVois-Pro software runs as root by default.

Starting JeVois software manually

If you have switched to Console boot, after you login (either as jevois/jevois or root/jevois), you can start the JeVois software from the command-line:


Note that the GPU drivers provided by ARM for our chip (Amlogic A311D) work in full-screen framebuffer mode only. So they work perfectly when booting in JeVois-Pro mode or Console mode. But if you run sudo from a terminal in X-windows, you will get conflicts between two graphical interfaces (X-windows and the JeVois GUI). You will see 2 mouse pointers, some X windows will refresh on top of the JeVois display, etc. Thus, if you want to run manually, do it from the console mode.

When you are in console mode, you can start X-windows by typing:


and when you logout from X, you will get back to your console.

This is very useful for development. You would do as follows:

  • switch to console boot and reboot
  • login as root/jevois
  • run
  • if you want to exit, activate the allowquit parameter of the Graphical User Interface (you need to turn on showing system parameters first). Or you could also start with --gui --allowquit which will allow you to exit JeVois software when you press the ESC key.
  • if you need to edit some files, download some files, etc and you like to do that in X-windows, then startx and logout from it when you are done.
  • then you can run again, etc.

WiFi or wired networking

See JeVois-Pro: Connecting to a wired or WiFi network

Enabling 4K display resolution

Do this by editing the hdmi value in /boot/env.txt on the microSD card. For example, for 4K at 30Hz:


Note that the camera will overall run a bit slower at 4K than at the default 1080p. We posit that this is due to more contention on the memory bus, as we use DMA all the way from camera sensor to GPU to display, so the CPU workload should not significantly increase at 4K.

Overclocking the CPU

Overclocking the CPU to 2.4 GHz (big cores, default is 2.208 GHz) and 2.208 GHz (little cores, default 1.8 GHz) is quite stable in our testing, especially if you make sure your cooling is strong (see JeVois-Pro Adjusting Fan Speed to edit fan settings).

First, you need to enable overcloking by editing /boot/env.txt on the microSD card:

# Maximum CPU Frequency of Little Core A53
# 500/667/1000/1200/1398/1512/1608/1704/1800(default)/1908/2016/2100/2208
# Maximum CPU Frequency of Big Core A73
# 500/667/1000/1200/1398/1512/1608/1704/1800/1908/2016/2100/2208(default)/2304/2400

This just sets the maximum possible frequency. But by default, the operating frequencies are still 2.2/1.8 GHz at boot time.

Then reboot JeVois-Pro and, in the GUI, select the Parameters tab, then enable "Show System Parameters", and under "Engine Options" you can set the desired cpu max speeds. You can set those values in the params.cfg config file (see Config tab in the GUI) if you want them to be the default at boot time.