Unicorn Hat HD: no lights, no errors

Support
1

Hi support

I’m trying to run up the hat from my order (#PI247669) for the first time but it’s dark. The python snippets run without errors but I see no lights. I read somewhere the hat should illuminate when plugged in? I’m not seeing that.

Is there something I did wrong or something else I can try to probe the hardware?

I’ve upgraded via apt.

I tried the explorer hat from the same purchase and that worked ok.

pi@msp-raspberrypi:~/Pimoroni/unicornhathd/examples $ uname -a
Linux msp-raspberrypi 4.14.34-v7+ #1110 SMP Mon Apr 16 15:18:51 BST 2018 armv7l GNU/Linux

pi@msp-raspberrypi:~/Pimoroni/unicornhathd/examples $ python --version
Python 2.7.13

pi@msp-raspberrypi:~/Pimoroni/unicornhathd/examples $ ll ~/Pimoroni/unicornhathd/
total 16
drwxr-xr-x 3 pi pi 4096 May 21 15:13 examples-backup/
drwxr-xr-x 3 pi pi 4096 May 21 15:13 projects-backup/
drwxr-xr-x 3 pi pi 4096 May 21 15:38 examples/
drwxr-xr-x 3 pi pi 4096 May 21 15:38 projects/

pi@msp-raspberrypi:~/Pimoroni/unicornhathd/examples $ python matrixhd.py 
Matrix

Follow the white rabbit...

^C

pi@msp-raspberrypi:~/Pimoroni/unicornhathd/examples $ python demo.py 
Unicorn HAT HD: demo.py

This pixel shading demo transitions between 4 classic graphics demo effects.

Press Ctrl+C to exit!

Cheers

2

Have to ask the obvious, pressed down firmly on the GPIO header? I think that has the thinner SMT header, even when its on all the way some bare pins show so its not always obvious if its on fully or not.

3

Forum only allows one image so alas I dropped this from the last post:

4

Looks OK to me. I’ve uploaded more than one pic in a post. It may be based on how many bytes they are don’t know. The other way to do it is put them in your OneDrive folder and post a link to that.
I don’t know about the Unicorn Hat but my Sense hat shows the Rainbow on its LED matrix during boot up.
Sounds like you may have got a dud, rare but it happens sometimes. If you click Shop at the top of the Page, then scroll all the way to the bottom, there is a Contact Us link to report your issue. I’d also put a link to this thread in it. Or just wait for somebody from Pimoroni to post here, they are usually pretty quick.

5

Thanks for taking a look @alphanumeric - I’ll ping them now.

FWIW - it’s cos I’m new on the forum so it limited my image count per post. They were external, public Dropbox links but Discourse did some magic inlining of the image anyway!

6

Ah, OK, yeah a lot of forums do that to prevent the one time sign up to spam them.

7

Hm, no errors either! Is it possible you have another script running that could be interfering with the Unicorn HAT HD?

Anything messing with pins BCM 8, 9, 10 or 11 could cause an issue: https://pinout.xyz/pinout/unicorn_hat_hd

You can often check this by looking at “ps aux | grep python” to see if any rogue Python scripts are left running, and make sure nothing’s in crontab or /erc/rc.local to run on boot that shouldn’t be.

8

Hi @gadgetoid - this is a brand new board and the first hat I tried to install / run. Nothing else is running and no rogue Python processes.

Is there something lower level we can try to test the comms?

This is after a reboot:

pi@msp-raspberrypi:~ $ ps -aux | grep python
pi         998  0.0  0.0   4372   540 pts/0    S+   16:49   0:00 grep --color=auto python
pi@msp-raspberrypi:~ $ ps -ef | grep python
pi        1000   979  0 16:50 pts/0    00:00:00 grep --color=auto python
pi@msp-raspberrypi:~ $ pwd
/home/pi
pi@msp-raspberrypi:~ $ cd Pimoroni/unicornhathd/
examples/        examples-backup/ projects/        projects-backup/ 
pi@msp-raspberrypi:~ $ cd Pimoroni/unicornhathd/examples
pi@msp-raspberrypi:~/Pimoroni/unicornhathd/examples $ python demo.py 
Unicorn HAT HD: demo.py

This pixel shading demo transitions between 4 classic graphics demo effects.

Press Ctrl+C to exit!

I subsequently tested a connection to the Explorer Hat Pro just to make sure it wasn’t the GPIO pins and all was ok.

9

I’d say it’s faulty - and it looks like support agrees and a replacement is in the pipeline for you?

10

Hi there,

I have an identical problem, except I’m using a Pi 4. Can I confirm that the Unicorn Hat HD works on the Pi4 before contacting support for a replacement?

Thansk,

Sam.

11

Hi,

It’s OK, I figured it out. the software we were using was for the Unicornhat, not Unicornhat HD. Once we installed the HD version it worked fine.

It took me a couple of hours to figure this basic problem out (I’m very much a beginner) so hope this helps someone else.

Sam