Unicorn HAT output not uniform

Support
1

Dear Pimoroni,

I got a non uniform light coming out of my HAT, only for the red component

IMG_20220808_141629
IMG_20220808_1416291920×2560 148 KB

In green and blue the LED are uniformly shining.

Do I miss something or is it a possible defect?

I installed the library with:

sudo apt-get install python3-pip python3-dev python3-spidev
sudo pip3 install unicornhathd

And did run

sudo raspi-config nonint do_spi 0
sudo reboot

And i use the following code with python 3.9:

import logging
import time
import numpy
import unicornhathd


logging.getLogger().setLevel(logging.DEBUG)

timefull = 25

unicornhathd.brightness(0.5)

shp = unicornhathd.get_shape()
logging.debug("Shape of the array is: {}".format(shp))

colors = [[255, 0, 0], [0, 255, 0], [0, 0, 255]]

for color in colors:
    for ix, iy in numpy.ndindex(shp):
        unicornhathd.set_pixel(ix, iy, *color)

    unicornhathd.show()

    time.sleep(timefull)

    unicornhathd.clear()

And I forgot to say

Rasperry Pi 3B or 3B+

With latest Bullseye OS

Best

2

IMG_20220808_141657
IMG_20220808_1416571920×2560 155 KB

3

After testing another Raspberry Pi I still get a non uniform red output.

IMG_20220808_144912
IMG_20220808_1449121920×1440 98.9 KB

5

This is my test code for the HD. Might be worth running it to see if you get the same weirdness with red?

#!/usr/bin/env python

import time
import unicornhathd

unicornhathd.brightness(0.6)

while True:
    
    unicornhathd.clear()
    unicornhathd.set_all(255, 0, 0)
    unicornhathd.show()
    time.sleep(10)

    unicornhathd.clear()
    unicornhathd.set_all(0, 255, 0)
    unicornhathd.show()
    time.sleep(10)

    unicornhathd.clear()
    unicornhathd.set_all(0, 0, 255)
    unicornhathd.show()
    time.sleep(10)
    
    unicornhathd.clear()
    unicornhathd.set_all(255, 255, 255)
    unicornhathd.show()
    time.sleep(10)
6

Nope same issue
(was not aware of this set_all() function, but it is relatively the same as my code)

Here is a picture of the white light in your test code, you can see some LED are more blue than other (because of the lack of the red)

IMG_20220808_194254
IMG_20220808_1942541920×2560 477 KB

7

Else here is some picture with only two LED on.
You can see the difference (not easy, but the left LED is Brighter than the right one).

IMG_20220808_195735
IMG_20220808_1957351920×2560 128 KB

8

Sorry I didn’t reply sooner. It looks like a hardware issue to me. There is a link on the shop page to contact tech support about it.
Contact Us for Raspberry Pi Technical Support - Pimoroni

9

Thanks for your guidance
Have a great day