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by Davespice
Tue Jan 09, 2018 11:23 am
Forum: Astro Pi
Topic: Color in a picture
Replies: 3
Views: 136

Re: Color in a picture

Something like this would do it;

Code: Select all

from PIL import Image
import numpy

file_name = "dave.jpg"

img = Image.open(file_name)

chan_red, chan_green, chan_blue = img.split()[0:3]
arr_red = numpy.asarray(chan_red).astype('float32')

print(numpy.mean(arr_red))
by Davespice
Wed Dec 20, 2017 10:57 am
Forum: Astro Pi
Topic: sleep vs. timedelta
Replies: 2
Views: 305

Re: sleep vs. timedelta

Hi Gail Okay the point there is that some of the functions, specifically the orientation ones are based on something called a kalman filter - which is where the pitch, roll and yaw angles are stored in memory and are updated each time you read from the sensor. If you don't read the sensors often eno...
by Davespice
Tue Dec 19, 2017 8:44 am
Forum: Astro Pi
Topic: Can you measure the pH of the water vapour?
Replies: 1
Views: 229

Re: Can you measure the pH of the water vapour?

Hi there, I'm afraid not.

The humidity sensor can tell you the amount of water vapour present though.
by Davespice
Thu Dec 07, 2017 3:34 pm
Forum: Astro Pi
Topic: Mission Space Lab webinar replay (30 November 2017)
Replies: 0
Views: 252

Mission Space Lab webinar replay (30 November 2017)

Those of you who're doing Astro Pi Mission Space Lab, the replay of the webinar can be found here:
https://astro-pi.org/updates/mission-sp ... g-webinar/
by Davespice
Thu Dec 07, 2017 3:32 pm
Forum: Astro Pi
Topic: Sense HAT help
Replies: 2
Views: 317

Re: Sense HAT help

You can get started by looking through this resource: https://projects.raspberrypi.org/en/projects/getting-started-with-the-sense-hat Get a bit more familiar with everything and then look at the code example at the bottom of this page: https://pythonhosted.org/sense-hat/api/#joystick That should giv...
by Davespice
Thu Dec 07, 2017 3:20 pm
Forum: Astro Pi
Topic: Use of PyEphem
Replies: 7
Views: 583

Re: Use of PyEphem

I normally just use sudo pip3 install ephem So ephem as opposed to pyephem. You might find that installing these two packages helps sudo apt-get install libc6 libc6-dev Please also check out the Mission Space Lab webinar which explains how to use it; https://www.youtube.com/watch?v=WYjaAZcWIPg&t=7760
by Davespice
Wed Dec 06, 2017 8:43 am
Forum: Astro Pi
Topic: PiCamera as Luminosity Sensor?
Replies: 7
Views: 553

Re: PiCamera as Luminosity Sensor?

If you're happy with decoding some binary you could take pictures in raw YUV format, where Y is luminance.
More info here (including how the binary data is represented): http://picamera.readthedocs.io/en/relea ... yuv-format
by Davespice
Tue Dec 05, 2017 9:24 am
Forum: Astro Pi
Topic: Slow Astro Pi Code
Replies: 8
Views: 592

Re: Slow Astro Pi Code

Ah so, well done, so this might be your first encounter with code profiling! If you go onto be a games developer this kind of thing becomes your life. There are special tools out there which let you identify the slow parts of your code so that you can concentrate on improving them. For now though I ...
by Davespice
Mon Dec 04, 2017 8:48 am
Forum: Astro Pi
Topic: Error can't figure out "module 'sense-hat' has not attribute 'SenseHat'
Replies: 10
Views: 622

Re: Error can't figure out "module 'sense-hat' has not attribute 'SenseHat'

I might suggest to zip up the whole sensehatscripts folder and put that online for us to look at.
by Davespice
Mon Dec 04, 2017 8:46 am
Forum: Astro Pi
Topic: Slow Astro Pi Code
Replies: 8
Views: 592

Re: Slow Astro Pi Code

Hi there; Just quickly looking at your code I've identified a line which is quite computationally costly inside your main loop; Try moving this line outside of your while loop, it doesn't need to be run every time - you just need to call the compute method every time. tle_rec = ephem.readtle(name, l...
by Davespice
Tue Nov 28, 2017 9:31 am
Forum: Astro Pi
Topic: Announcing the 2017-18 European Astro Pi challenge!
Replies: 3
Views: 1179

Re: Announcing the 2017-18 European Astro Pi challenge!

Thanks to everyone who participated in Mission Zero and Mission Space Lab this year! We will be in touch soon. Those of you who missed it this year, please sign up to our mailing list to find out about next year's challenge https://astro-pi.org/#mc-embedded-subscribe-form
by Davespice
Tue Nov 28, 2017 9:25 am
Forum: Astro Pi
Topic: Error can't figure out "module 'sense-hat' has not attribute 'SenseHat'
Replies: 10
Views: 622

Re: Error can't figure out "module 'sense-hat' has not attribute 'SenseHat'

Ah, sometimes you get strange behaviour like this if you have a .py file which has the same name as a module.
Can you rename the file /home/pi/Desktop/sensehatscripts/random.py to something else? Like my_random.py and see if that makes any difference?
by Davespice
Sat Nov 25, 2017 8:40 pm
Forum: Astro Pi
Topic: Use of OpenCV
Replies: 6
Views: 676

Re: Use of OpenCV

Hi Mark Yes we were getting quite bad window reflections during night passes. This wasn't a problem for that experiment because it was programmed to discard night images anyway, but this logic was based on an average colour check and because of the reflection it meant that the night side images were...
by Davespice
Tue Nov 21, 2017 4:40 pm
Forum: Astro Pi
Topic: Life in Space - Pi NoIR orientation
Replies: 1
Views: 428

Re: Life in Space - Pi NoIR orientation

Hi Stephen So the camera is sideways in the case due to the length of the ribbon cable - if you hold the Astro Pi case looking at the camera with LED hole in the top right - this is the default "up" orientation for the camera. If you change the desktop background on your Astro Pi you should find, at...
by Davespice
Tue Nov 21, 2017 9:04 am
Forum: Astro Pi
Topic: Use of PyEphem
Replies: 7
Views: 583

Re: Use of PyEphem

Oh sorry! :)
by Davespice
Tue Nov 21, 2017 8:58 am
Forum: Astro Pi
Topic: Use of OpenCV
Replies: 6
Views: 676

Re: Use of OpenCV

Hi Mark OpenCV is currently not installed on the Astro Pi units on orbit, so we will just install whatever is the latest version. As a side note about the camera, please take note of this blog post . Particularly the blue filter (there will be one supplied with your Pi NoIR camera). The Blue filter ...
by Davespice
Mon Nov 20, 2017 9:22 am
Forum: Astro Pi
Topic: Announcing the 2017-18 European Astro Pi challenge!
Replies: 3
Views: 1179

Re: Announcing the 2017-18 European Astro Pi challenge!

Hi folks, this is the last week to participate in Mission Zero - after the 26th you'll have to wait until next September!
by Davespice
Mon Nov 20, 2017 9:20 am
Forum: Astro Pi
Topic: Use of PyEphem
Replies: 7
Views: 583

Re: Use of PyEphem

Hi Mark I'll be explaining this during the webinar (which your teacher will get an email about soon). But basically if you get chosen for space-flight a few minor modifications are made to your code to make it obey the Astro Pi MCP (Master Control Program). As part of those edits, if I see your code...
by Davespice
Mon Nov 20, 2017 9:16 am
Forum: Astro Pi
Topic: Use of OpenCV
Replies: 6
Views: 676

Re: Use of OpenCV

Hi there

OpenCV was used on the Astro Pi units during the Peake mission in 2016. So there's no problem with requiring it, we're expecting a lot of teams to want to use it.

Many thanks

Dave
by Davespice
Wed Nov 01, 2017 9:22 am
Forum: Astro Pi
Topic: AstroPi Mission Zero Certificates
Replies: 1
Views: 569

Re: AstroPi Mission Zero Certificates

Have you shown them this video? https://vimeo.com/172737314 You will receive an email with links to download PDF certificates for each of the teams that submitted using your classroom code. We haven't finalised the design just yet but my plan is for them to show a map of the world with an ISS icon s...
by Davespice
Wed Nov 01, 2017 9:18 am
Forum: Astro Pi
Topic: Looking for team
Replies: 1
Views: 532

Re: Looking for team

Did you manage to find anyone?
by Davespice
Wed Nov 01, 2017 9:16 am
Forum: Astro Pi
Topic: Announcing the 2017-18 European Astro Pi challenge!
Replies: 3
Views: 1179

Re: Announcing the 2017-18 European Astro Pi challenge!

Update. Mission Space Lab registration is now closed, those of you who submitted an idea should receive an email from the European Space Agency by 7 November to let you know if you've been selected for phase two. If so then shortly after a free Astro Pi kit will be shipped to you. Mission Zero is s...
by Davespice
Tue Oct 24, 2017 11:30 am
Forum: Astro Pi
Topic: Using an R-Pi 3 in the AstroPi (Confirmed Observation)
Replies: 4
Views: 945

Re: Using an R-Pi 3 in the AstroPi (Confirmed Observation)

Ah yes, this is a known issue. Even with the old Pi 1 B+ there is some thermal leak from the CPU into the temperature sensors, we've even seen student experiments (which were run on board the ISS) where the they attempted to calibrate out the thermal leak. Have a look here for an example. It's actua...
by Davespice
Tue Oct 24, 2017 11:25 am
Forum: Astro Pi
Topic: How will GPIOZero Effect Astro Pi Programming?
Replies: 5
Views: 868

Re: How will GPIOZero Effect Astro Pi Programming?

It's perfectly valid and okay to use a Pi 3 in an Astro Pi, there's even a printable base file which has the LED holes moved over to the other side. The only advice we give out to people is to avoid using a metal stand-off next to the little white WiFi chip, as this will degrade WiFi performance.
by Davespice
Mon Oct 23, 2017 2:57 pm
Forum: Astro Pi
Topic: How will GPIOZero Effect Astro Pi Programming?
Replies: 5
Views: 868

Re: How will GPIOZero Effect Astro Pi Programming?

So you don't need to use gpiozero or any GPIO library, there's a device tree overlay that you enable and this causes the buttons to type the letters u, d, l, r (top quad), and a, b (bottom pair) when pressed. Since the Sense HAT joystick is mapped to the cursor keys and Enter (for the middle click) ...

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