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Sense Hat Issue

Posted: Sat Feb 13, 2016 12:30 am
by lmoss30
I am having issues with my sense hat since upgrading to the new raspbian release, i re imaged ny sd card with the latest noobs incase something went wrong.

basically i can use all the sensor features but i cant make the led matrix work

any ideas

Re: Sense Hat Issue

Posted: Sat Feb 13, 2016 1:56 am
by ShiftPlusOne
Could you please provide more information?

What output are you seeing, what are you trying to do and so on....

Re: Sense Hat Issue

Posted: Sat Feb 13, 2016 4:48 pm
by lmoss30
Hi so the reading of the sensors deem to work

I'd I do a show_message it doesn't raise an error but nothing appears on matrix but it looks like the code is still running

Re: Sense Hat Issue

Posted: Wed Feb 17, 2016 8:58 pm
by lmoss30
Hi There,

I have been doing some further testing today on the problem I mentioned here

I have written the following

from sense_hat import SenseHat
sense=SenseHat()

sense.set_pixel(1,1,255,,0)

then do a
sense.get_pixel(1,1)

the return value is (248,0,0)

I am assuming this means it has believed to have set pixel 1,1 with the right colour yet no colour is shown on the led matrix,

If I do a sense.temperature it returns the current temperature.

any ideas?

Re: Sense Hat Issue

Posted: Wed Feb 17, 2016 9:27 pm
by lmoss30
Think I may have just seen an issue on the pcb fb1 looms like it has a missing component guessing it been knocked at some point

Can I just solder a link across this?

Re: Sense Hat Issue

Posted: Thu Feb 18, 2016 7:56 pm
by Davespice
lmoss30 wrote:from sense_hat import SenseHat
sense=SenseHat()

sense.set_pixel(1,1,255,,0)

then do a
sense.get_pixel(1,1)

the return value is (248,0,0)
Hi there!
This is an expected behavior due to how the numbers are bit shifted to fit into the Linux frame buffer memory.
It's explained in the API documentation here: http://pythonhosted.org/sense-hat/api/#get_pixels

Re: Sense Hat Issue

Posted: Fri Feb 19, 2016 10:53 am
by lmoss30
thanks for the response,

could you comment on the missing component on my board, it has been knocked at some point, can i solder a link across?

Re: Sense Hat Issue

Posted: Fri Feb 19, 2016 11:55 am
by Davespice
Can you post a picture with a circle drawn around the area of the mission component?
Try and make sure it's in focus, blurry pictures won't help. Then I should be able to tell.

Re: Sense Hat Issue

Posted: Fri Feb 19, 2016 12:13 pm
by lmoss30
at work at the moment so will later but it was FB1, location directly diagonal to the joysstick

Re: Sense Hat Issue

Posted: Fri Feb 19, 2016 12:24 pm
by Davespice
Ah if it's FB1 in the top left corner, this is a ferrite bead that connects 5 volts to the board. You can replace this with a wire bridge.

Image

Re: Sense Hat Issue

Posted: Sat Feb 20, 2016 10:25 pm
by lmoss30
Thanks for confirming that, I no have a working sense hat again :)

What does the ferrite bead do?

Re: Sense Hat Issue

Posted: Tue Feb 23, 2016 5:12 pm
by Davespice
It's just used to suppress or filter the amount of high frequency electromagnetic interference (EMI) coming from the 5 volt power supply you're using.