Pi-Top with unicorn hat HD

I received my pi-top yesterday and all seems to be working fine, i am however having a few issues with the unicron hat HD, flickering the screen whenever i use it. (https://twitter.com/ajalexsmith/status/887392548800647168)
i was wondering if anyone else had had any issues? my thoughts are its a power related issue but i’m not too sure

many thanks


Update: i have been playing around and it seems to be changing the unicornhathd brightness does the same to the pi-top. is there any way to change this?

Firstly: I completely agree with Guru there, MORE BLINKY LIGHTS! However, you do need a screen to first program the blinky lights, which does pose a problem…

To that end, what power supply are you using (particularly the ampage)? I presume some sort of official supply for the Pi-top itself? The Raspberry Pi 3 uses a 2 amp power supply, so I’m guessing the Pi-top would need much more power when lighting both the screen and the Unicorn Hat at full brightness.

Sadly after buying the pi-top I can’t afford any more blinky lights 😂😂I am running the pi off the lipo battery. I’m not sure specifically on the power output but the charging cable has an output of 18 volts at 3A

What is the LIPO battery connected to? And how does that power the Pi?

it’s all internal through the pi-top circuitry and power management board

Ok, thanks. Doah, should just googled it. My bad. I see a cable connected to the GPIO, that appears to go to the other board. What does that do? If it used some of the GPIO pins etc, there may be a conflict with that and the unicorn HD hat.

That handles the screen etc. This is what I was thinking, if only the pi-top circuitry was on PinOut! I have set up a support ticket with pi-top so should hopefully get a bit more information

How are you hooking the unicorn hat and the Pi Top display cable up at the same time? Or are you?

Try driving the Unicorn HAT HD to black, instead of reducing the brightness, IE: set all pixels to 0,0,0 and update it constantly. If the screen still flickers then this would indicate a problem other than power. If it doesn’t, then it’s just the power supply. Even at conservative estimates on low brightness, Unicorn HAT HD can easily pull 1A. It’s a hungry, hungry hippo!

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I got a reply from pi-top last night saying:
The Unicorn HAT HD and the pi-top HUB are using some of the same SPI communication lines for screen brightness and power monitoring features so this is the cause of the error.
I have informed the hardware team of this instance.
A work around for the moment is to install Raspbian onto your SD card as this will allow you to use the Unicorn HAT HD with the pi-top.
I installed raspbian instead of the pi-top os and it seems to have fixed the issue :)
Many thanks for all your help!

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