Ubiquity image with Sense HAT does not work

Pi Image
1

Hi,
I’m trying to follow the Getting Started steps to test the Sense HAT on my Raspberry Pi 3B+.
I’m using the Ubiquity Robotics image.
When I start the simple python script, I get an error because it is impossible to find the LED matrix.
The Rpi communicate towards I2C with and Attiny that control the matrix.
The communication is working because I can detect the other modules and sensors of the board.
It seems there is a conflict with the overlay features of the image. Actually, if I comment the dtoverlay=ubiquity_led_buttons in the /boot/config.txt file, the script can run without errors.
In this way, the Rpi wifi does not work.
What should I modify to have both the functionalities?

Thanks

2

Hi @francesca,

Could you link to the script that is failing?

Also in what way is the wifi not working when you disable the overlay? It should still work… unless there is a bug somewhere.

Rohan

3

Here is the script
https://projects.raspberrypi.org/en/projects/getting-started-with-the-sense-hat/4
Is the very first step to test the module

from sense_hat import SenseHat
sense = SenseHat()
sense.show_message(“Hello world”)

Yes, this is also my question, because I need both: the module and also the wifi access.

4

What do you mean by the wifi not working? Is AP mode not working? Does wlan0 show up when you run ifconfig?

5

Yes, the AP mode is not working if I comment the overlay in /boot/config.txt

This is the result with the overlay commented:

photo_2019-12-09_17-28-14
photo_2019-12-09_17-28-141280×960 162 KB

6

Ok, one more debugging step. Can you run sudo systemctl status pifi and provide the output?

7

Here is the output:

photo_2019-12-10_08-50-55
photo_2019-12-10_08-50-551280×581 76.2 KB

Thanks for the support!

8

@francesca

Congratulations! You found a bug in pifi. I opened a github ticket here https://github.com/rohbotics/pifi/issues/16

For a workaround, please edit /etc/pifi/pifi.conf, and comment out the lines with status_led and button_device_name. This should solve with AP mode not starting.

Rohan

9

Ignore all that. I got it to work too. For some reason I also need to set the Monitor settings in raspi-config.

So changes were:
#dtoverlay=ubiquity_led_buttons
dtoverlay=rpi-sense
status_led=None
button_device_name=None
raspi-config

  1. 7 Advanced Options
  2. A5 Resolution
  3. DMT Mode 4 640x480 60Hz 4:3

Hi Francesca, did you end up getting this working?

I tried commenting out dtoverlay=ubiquity_led_buttons in the config.txt file, but then I can’t connect to the Raspberry Pi, and get the following error when I tried to connect via ssh:

ssh ubuntu@test.local
ssh: Could not resolve hostname test.local: Name or service not known

This persisted even when I commented out status_led and button_device_name from the /etc/pifi/pifi.conf. I also tried setting them both to None but that didn’t allow me to connect either?

If I unplug the Sense Hat with those settings changed it connects again via SSH?

If I don’t comment out dtoverlay=ubiquity_led_buttons and have the Sense Hat attached, it connects fine, but I can’t run any programs and get the following error:

raise OSError('Cannot detect %s device' % self.SENSE_HAT_FB_NAME)
OSError: Cannot detect RPi-Sense FB device

From a basic program like:
from sense_hat import SenseHat
sense = SenseHat()
sense.show_message(“Hello world”)

The RTIMULibDrive11 program works though and outputs readings from the Sense Hat for the roll, pitch, yaw, and temperature fine.

Adding dtoverlay=rpi-sense to the config.txt file didn’t fix it either?

Going to try on another raspberry pi image, to check the Sense Hat works now.

1 Like
10

@mackhina Glad you got it working. Good luck on your project.

The SSH issue is seperate, sometimes the images refuses to SSH for a while after booting up, we are working on a fix for the next image.

Rohan