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by Davespice
Fri Oct 13, 2017 8:53 am
Forum: Astro Pi
Topic: Python and the senseHAT Joystick
Replies: 3
Views: 2105

Re: Python and the senseHAT Joystick

I think I see what's happening. When the joystick is pressed you get two events, one for pressed and another for released. If you're programming a game you might want the player to say keep firing while a button is held down. You wouldn't be able to code that if the event system only told you about ...
by Davespice
Thu Oct 12, 2017 8:59 am
Forum: Astro Pi
Topic: Browsers for Mission Zero - which ones? - online safety?
Replies: 9
Views: 2751

Re: Browsers for Mission Zero - which ones? - online safety?

Just to chime in here, we have had one report of the .io top level domain being blocked in a school. This may be because of agar.io which was a popular time waster game a while back. If that block is in place in your school you will not be able to access the Mission Zero code editor which uses a .io...
by Davespice
Mon Oct 09, 2017 12:54 pm
Forum: Astro Pi
Topic: Sense HAT What is I2C and do I need to enable?
Replies: 15
Views: 4774

Re: Sense HAT What is I2C and do I need to enable?

In the latest image of Raspbian Stretch I believe it is turned on by default, in which case enabling it in that menu is a red herring.
by Davespice
Mon Oct 09, 2017 12:53 pm
Forum: Astro Pi
Topic: Sense Hat Error
Replies: 8
Views: 4234

Re: Sense Hat Error

It will be one of two things, either a physical connection problem between the Sense HAT and the Pi or the EEPROM (a chip on the Sense HAT which announces what type of HAT it is) has become corrupted. Following the advice above about config.txt should do the trick, but if not then check the HAT is p...
by Davespice
Tue Oct 03, 2017 10:45 am
Forum: Astro Pi
Topic: Sense Hat and greek fonts
Replies: 4
Views: 2345

Re: Sense Hat and greek fonts

The characters are 5x7 so it's even worse! I imagine they would be able to get something which looks better than Latin-1 but whether it would be easily readable is another question. Also one of the reasons we only went with Latin-1 in the first place.
by Davespice
Mon Oct 02, 2017 8:06 am
Forum: Astro Pi
Topic: Sense Hat and greek fonts
Replies: 4
Views: 2345

Re: Sense Hat and greek fonts

So the Sense HAT library is provided with the Latin-1 character set built in, but it does give the user the option to provide their own text assets. If you look here you'll see the files named sense_hat_text.txt and sense_hat_text.png . The text file is used to index the order in which the character...
by Davespice
Mon Oct 02, 2017 7:46 am
Forum: Astro Pi
Topic: Astro Pi initial Setup
Replies: 2
Views: 1787

Re: Astro Pi initial Setup

The Astro Pi kits, for this year's challenge, will be using this NOOBS image which is based on Jessie. This will give you working push buttons out of the box.
by Davespice
Mon Sep 25, 2017 11:18 am
Forum: Astro Pi
Topic: Announcing the 2017-18 European Astro Pi challenge!
Replies: 3
Views: 2137

Announcing the 2017-18 European Astro Pi challenge!

Astro Pi is back! Today we’re excited to announce the 2017-18 European Astro Pi challenge in partnership with the European Space Agency (ESA). We are searching for the next generation of space scientists! Background Astro Pi is an annual science and coding competition where student-written code is r...
by Davespice
Wed Sep 20, 2017 1:51 pm
Forum: Astro Pi
Topic: Save the date: the European Astro Pi Challenge is back!
Replies: 3
Views: 1809

Re: Save the date: the European Astro Pi Challenge is back!

Thanks for this, check the Raspberry Pi blog on Monday!
by Davespice
Fri Sep 08, 2017 12:11 pm
Forum: Astro Pi
Topic: OSError: Cannot detect RPi-Sense FB device
Replies: 10
Views: 11210

Re: OSError: Cannot detect RPi-Sense FB device

I think you have a faulty Sense HAT, I would return it to the retailer.
by Davespice
Tue Sep 05, 2017 9:11 am
Forum: Astro Pi
Topic: OSError: Cannot detect RPi-Sense FB device
Replies: 10
Views: 11210

Re: OSError: Cannot detect RPi-Sense FB device

It may be that the EEPROM is not working then. This is a small chip which is used to identify the HAT to the Raspberry Pi. So it may be that it's just not detecting the HAT correctly. You can force the Raspberry Pi to believe a Sense HAT is connected though and that can sometimes solve the rainbow-f...
by Davespice
Fri Sep 01, 2017 3:54 pm
Forum: Astro Pi
Topic: OSError: Cannot detect RPi-Sense FB device
Replies: 10
Views: 11210

Re: OSError: Cannot detect RPi-Sense FB device

The white flash makes me think the AVR chip on the Sense HAT, which drives the LEDs, has had it's memory corrupted.
If you don't see the rainbow test card then something is not right with the hardware for sure. Do you have another Pi you can try it on?
by Davespice
Fri Sep 01, 2017 2:50 pm
Forum: Astro Pi
Topic: Magnetometer Axis Label Identification
Replies: 11
Views: 4540

Re: Magnetometer Axis Label Identification

Here's a link to the data sheet for the IMU sensor, of which the magnetometer is a part.
I hope this helps.

Many thanks

Dave
by Davespice
Fri Aug 18, 2017 3:57 pm
Forum: Astro Pi
Topic: Sense Hat Magnetometer - Reporting incorrect degrees
Replies: 5
Views: 3393

Re: Sense Hat Magnetometer - Reporting incorrect degrees

There is the ellipsoid fit calibration you can use, more info on this thread.
viewtopic.php?f=104&t=109064&p=750616#p810193
by Davespice
Tue Aug 15, 2017 12:09 pm
Forum: Astro Pi
Topic: Sense HAT rainbow colors latched on power up
Replies: 2
Views: 2536

Re: Sense HAT rainbow colors latched on power up

Hi there Okay so if that happens it either means the EEPROM on the Sense HAT isn't working, or the EEPROM ID pins are not connected between the HAT and the Pi. Which happens if you're using a shorter pin header. The good news is you can override this by adding a line to config.txt . Open a Terminal ...
by Davespice
Thu Aug 10, 2017 1:52 pm
Forum: Astro Pi
Topic: Sense HAT API for non English speakers
Replies: 1
Views: 1744

Sense HAT API for non English speakers

During one of my meetings with ESA a teacher pointed out that non English speakers have to parrot-fashion learn the meanings of the Sense HAT API functions. So, as an experiment, I've created this GitHub gist to show how Python class inheritance can be used to translate the method and parameter name...
by Davespice
Thu Aug 10, 2017 9:06 am
Forum: Astro Pi
Topic: Astro pi pin badges
Replies: 0
Views: 1144

Astro pi pin badges

What do you all think of these new pin badges? They're suppose to look like the top of the Astro Pi flight unit.

Image

More pics here: https://twitter.com/Raspberry_Pi/status ... 1779907584
by Davespice
Thu Aug 10, 2017 8:59 am
Forum: Astro Pi
Topic: American "astro Pi"
Replies: 6
Views: 6981

Re: American "astro Pi"

Hi folks, we would really love to work with NASA on this but it's been quite hard to raise their interest in the project. What will definitely help is if they receive multiple enquiries from different people on the subject. You can try emailing the education contacts which you can get to through thi...
by Davespice
Thu Aug 10, 2017 8:54 am
Forum: Astro Pi
Topic: Sense Hat Magnetometer - Reporting incorrect degrees
Replies: 5
Views: 3393

Re: Sense Hat Magnetometer - Reporting incorrect degrees

Hi there So that function turns off the gyroscope and accelerometer then only uses the magnetometer to give you the angle. The magnetometer is actually perturbed by all the metal in the USB ports and any casing you've got. Calibration helps to mitigate it but doesn't make it perfect. What I think wi...
by Davespice
Thu Aug 10, 2017 8:47 am
Forum: Astro Pi
Topic: I highly recomend using a difusser with your Sense Hat
Replies: 3
Views: 2176

Re: I highly recomend using a difusser with your Sense Hat

Yeah this happens because the Sense HAT LEDs are pulsed at 60Hz, your digital camera refreshes a lot faster than that and therefore can actually take a picture between the pulses where the LEDs look like they're off. Humans don't see this because we have persistence of vision. The defuser will help ...
by Davespice
Thu Aug 10, 2017 8:40 am
Forum: Astro Pi
Topic: Astro Pi - Launcher/Main Program - Released?
Replies: 3
Views: 2046

Re: Astro Pi - Launcher/Main Program - Released?

Hi Scotty No the MCP was never released for security reasons. We've had a couple of enquiries about it over the years, it's actually not all that special. It's just a python program so doesn't have any clever memory-paging or voting system to avoid single event upsets and/or latch ups. It's job is j...
by Davespice
Thu Aug 10, 2017 8:32 am
Forum: Astro Pi
Topic: Sense HAT display adds random pixels
Replies: 1
Views: 1727

Re: Sense HAT display adds random pixels

Hmm, that should definitely not happen. You could add a clear command at the start of your code to help mitigate it;

Code: Select all

sense.clear()
Are you over-clocking the Pi?
Can you post the output of these Terminal commands too?

Code: Select all

uname -a
sudo vcgencmd version
by Davespice
Thu Aug 10, 2017 8:29 am
Forum: Astro Pi
Topic: Two sense hats that ocasionally show over 100% humidity.
Replies: 2
Views: 1713

Re: Two sense hats that ocasionally show over 100% humidity.

This is a known bug in the firmware, it's not your code. It can also vary slightly between different Sense HATs.
My recommendation is to clamp the sensor measurement to 100, like so:

Code: Select all

h = sense.get_humidity()
h = round(h)
if h > 100:
    h = 100
I hope this helps.
by Davespice
Thu Aug 10, 2017 8:27 am
Forum: Astro Pi
Topic: Change of encoding while writing to file
Replies: 2
Views: 1702

Re: Change of encoding while writing to file

Can you post the full code of your program, or a link to it please?
by Davespice
Thu Apr 13, 2017 12:02 pm
Forum: Astro Pi
Topic: American "astro Pi"
Replies: 6
Views: 6981

Re: American Pi

Hi Jeff Many thanks for asking this. Doing Astro Pi with NASA is something we would absolutely love to do. There is the possibility of ESA promoting Astro Pi to all members of the ISEB (International Space Education Board) of which NASA is a founding member, but I am not sure the status of that curr...

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