Display-o-Tron hat - no backlight, only bargraph LEDs (Support)


#1

I posted this in the Pi forums, I realise it should probably be here, because … well, it’s product support!

I’ve just attached my DOTHAT for the first time since getting it for Christmas. I’ve followed the lib install guide, and fired up backlight.py.

It runs without complaining, but the backlight doesn’t come on. All I can managed to get working is the bars (these just scan up and down in a loop) and the LCD shows “Such Rainbow!”.

The output for i2cdetect -l is:

i2c-1 unknown 3f804000.i2c N/A

… and the output of i2cdetect -y 1:

0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- -- -- -- -- -- -- -- -- -- -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- -- -- -- -- -- -- -- -- -- -- -- 2c -- -- -- 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 70: -- -- -- -- -- -- -- --

Can anyone share any things to try and get this working or does it look like this is a faulty board?

I have tried this on both Wheezy and Jessie with the same results.

Cheers,
Dave


#2

Which install instructions did you follow, perhaps there is a dependency issue.

Try:

curl -sS get.pimoroni.com/displayotron | bash

Then retry the example.


#3

Hi,

Yep, those are the very instructions. I went through them all again, everything checked out fine, installed fine, you name it (including the myriad VLC deps being installed). I have all the various kernel modules enabled. The software doesn’t complain, just the backlight doesn’t come on.

The more I try and get it to work, the more I’m convinced it’s a faulty board.


#4

yes, that seems quite likely to me too. I would shoot support an email!