Only half my lights are active on my UnicornHat


I’m sure I’m doing something wrong, but I’m not a hardware guy. So far I’ve been able to muddle along, but today I’m stumped.

I have a Raspberry Pi3. I have a camera installed and active. I decided to install one of Mausberry Circuit’s cool little rocker switches to turn on/off my Pi. I would like to install the Unicorn Hat by using GPIO PINS. I have included a picture below of my setup. Hopefully you can see what I’ve done. I followed the PIN set up from another post on this forum. I am using 2 (the first PIN on the right side), GND (the fifth PIN on the left side), and GPIO 18 (the 6th PIN on the right side).

Today I ran the following to install the Unicorn Hat software.
curl -sS | bash

I have run sudo apt-get update and upgrade.

Still when I run sudo ./ it says I’m using a Unicorn pHat and if I run sudo ./ I only get 4 of the 8 rows to light up.

Thanks for any assistance!


That is completely normal. The detection scheme probes the system for information registered by the Unicorn eeprom at boot time.

You should either wire up pin27/28 or just enforce the layout in your scripts with set_layout(unicornhat.HAT) as per instruction of


Indeed, you are correct. I’m a tad embarrassed. Thanks for your help! I’m shooting sparkling rainbows everywhere.