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by Davespice
Tue Feb 20, 2018 8:32 pm
Forum: Astro Pi
Topic: Numbers from last year?
Replies: 1
Views: 535

Re: Numbers from last year?

Here's the blog post from last year: https://www.raspberrypi.org/blog/europe ... i-winners/

We changed the format for this year's competition so teams are not winners at this point, they have to write the final report now and only win based on the merit of that report.
by Davespice
Tue Feb 06, 2018 8:40 am
Forum: Astro Pi
Topic: Accelerometer full scale range, SpaceLab Mission
Replies: 3
Views: 891

Re: Accelerometer full scale range, SpaceLab Mission

Ah I see what you mean. The numbers you get do have quite a bit of decimal accuracy so it might still be possible as is. During Tim Peake's flight in 2016 we did some long term data logging in multiple locations of the ISS. Looking at the accelerometer measurements from this is a useful way to chara...
by Davespice
Mon Feb 05, 2018 9:50 am
Forum: Astro Pi
Topic: How much disk space can be used for SpaceLab Mission
Replies: 1
Views: 532

Re: How much disk space can be used for SpaceLab Mission

Hi Stefano Technically there is no limit providing you can justify the science requirement for the disk space. We have a ground control team who can remotely connect to the Astro Pi from ground and keep downloading output data to free up disk space. The micro SD cards we're using on the ISS are 32 G...
by Davespice
Mon Feb 05, 2018 9:48 am
Forum: Astro Pi
Topic: Accelerometer full scale range, SpaceLab Mission
Replies: 3
Views: 891

Re: Accelerometer full scale range, SpaceLab Mission

Hi Stefano

I'm afraid you can't change the flight copy of RTIMULib.ini , the full data sheet for that sensor can be found here. Link is also on the Space Lab FAQ page.

The data sheet says it can do up to +-16 G.

I hope this helps.

Dave
by Davespice
Mon Feb 05, 2018 9:45 am
Forum: Astro Pi
Topic: How to trigger the camera based on ISS location
Replies: 7
Views: 1263

Re: How to trigger the camera based on ISS location

Yes of course. Just make an if statement that tests the sublat and sublong properties of the iss ephem object. Just replace A, B, X and Y with the numbers you want. iss_lat = degrees(iss.sublat) iss_long = degrees(iss.sublong) if iss_long > A and iss_long < B and iss_lat > X and iss_lat < Y: cam.cap...
by Davespice
Mon Feb 05, 2018 9:39 am
Forum: Astro Pi
Topic: How do I install OpenCV 3?
Replies: 3
Views: 852

Re: How do I install OpenCV 3?

Always check the FAQ, this is the last question at the bottom of the page;
https://astro-pi.org/missions/space-lab/faq/
by Davespice
Fri Feb 02, 2018 11:14 am
Forum: Astro Pi
Topic: Mission Zero Certs? :D
Replies: 2
Views: 822

Re: Mission Zero Certs? :D

Hi Mark The data should be downloaded to ground today and I will receive it either by this afternoon or early next week. So at this stage I would estimate that by middle of next week we will be able to send out the digital certificates. Many thanks Dave P.S. Be aware it might flood your Inbox if you...
by Davespice
Fri Feb 02, 2018 11:11 am
Forum: Astro Pi
Topic: Problems with OpenCV
Replies: 3
Views: 796

Re: Problems with OpenCV

Okay no worries, glad you managed to get it installed.
by Davespice
Fri Feb 02, 2018 11:10 am
Forum: Astro Pi
Topic: Camera Questions: Mission Space Lab; Life on Earth
Replies: 3
Views: 842

Re: Camera Questions: Mission Space Lab; Life on Earth

You can show the number on the LED matrix using the show_message function;

Code: Select all

dist = haversine(iss_long, iss_lat, target_long, target_lat)
sense.show_message("%s km" % round(dist))
by Davespice
Thu Feb 01, 2018 3:45 pm
Forum: Astro Pi
Topic: Mission Space Lab: Must code print text to the LED matrix?
Replies: 1
Views: 634

Re: Mission Space Lab: Must code print text to the LED matrix?

Yes that's enough. It just had to be enough to convince the crew that the Astro Pi hasn't crashed or become frozen. If they think it has they call down to ground to ask for someone to check it remotely. Also, if you can - avoid the colour red. As the crew are trained to spot and investigate any red ...
by Davespice
Thu Feb 01, 2018 3:44 pm
Forum: Astro Pi
Topic: Problems with OpenCV
Replies: 3
Views: 796

Re: Problems with OpenCV

Hi there, can you load this URL in the browser?
https://www.piwheels.hostedpi.com/simple/opencv-python/
by Davespice
Wed Jan 31, 2018 9:18 am
Forum: Astro Pi
Topic: Camera Questions: Mission Space Lab; Life on Earth
Replies: 3
Views: 842

Re: Camera Questions: Mission Space Lab; Life on Earth

Hi Darren You don't have to use Duck Duck Go on the Pi (it's just the default), you can navigate to the www address of whatever search engine does work on your network. To answer your questions: 1. Some of the target areas my students are interested in photographing are at high latitudes. Above what...
by Davespice
Tue Jan 30, 2018 10:03 am
Forum: Astro Pi
Topic: Camera Overlap
Replies: 3
Views: 753

Re: Camera Overlap

Good observation, that would be a problem if the target just clips the edge of the field of view. But if moving through the middle you'll get 3 or 4 good pictures. I try not to give out perfect code so that people use it as a starting point and learn from it. What you could do is have a greater trig...
by Davespice
Mon Jan 29, 2018 11:41 am
Forum: Astro Pi
Topic: Camera Overlap
Replies: 3
Views: 753

Re: Camera Overlap

Good question! So what you need to know about is something called ground sampling distance, or GSD for short. This the distance on ground represented by a single pixel of the camera. The Astro Pi training webinar says this is 161 meters per pixel. This was calculated using this GSD calculator tool a...
by Davespice
Mon Jan 29, 2018 11:32 am
Forum: Astro Pi
Topic: PILlow, PiCamera and rogue readings
Replies: 3
Views: 677

Re: PILlow, PiCamera and rogue readings

You could keep the preview going continuously if you wanted, so start the preview, your main loop, stop the preview.
by Davespice
Mon Jan 29, 2018 9:28 am
Forum: Astro Pi
Topic: PILlow, PiCamera and rogue readings
Replies: 3
Views: 677

Re: PILlow, PiCamera and rogue readings

Ah yes, you probably want to start the camera preview some seconds before you capture a photo to allow it to adjust to the light level. So for example: cam.start_preview() time.sleep(5) cam.capture(photoName) # Take photo of Earth cam.stop_preview() image = Image.open(photoName).convert('L') # conve...
by Davespice
Tue Jan 23, 2018 5:13 pm
Forum: Astro Pi
Topic: How to trigger the camera based on ISS location
Replies: 7
Views: 1263

Re: How to trigger the camera based on ISS location

I've just realised a bug in my code. 417 km is the horizontal width of the image, from the left side to the right. We want to check for distance from the center to the edge, so you should use 208 as the image_range value. I've updated the code example on GitHub.
by Davespice
Tue Jan 23, 2018 2:49 pm
Forum: Astro Pi
Topic: How to trigger the camera based on ISS location
Replies: 7
Views: 1263

Re: How to trigger the camera based on ISS location

I'm not sure I follow but I'll take your word for it. It will still be a blocking call unless you use something like multi-threading.
by Davespice
Tue Jan 23, 2018 9:49 am
Forum: Astro Pi
Topic: How to trigger the camera based on ISS location
Replies: 7
Views: 1263

Re: How to trigger the camera based on ISS location

Ah, that may be because the show message function is a blocking call. What that means is that if you call sense.show_message("a really long string of text") the whole message has to scroll on the LED matrix before the next line of code gets run. What I would suggest to do is just show an icon or a s...
by Davespice
Mon Jan 22, 2018 10:10 am
Forum: Astro Pi
Topic: Final Team Members
Replies: 1
Views: 591

Re: Final Team Members

Hi there, yes you can do that - provided it's a minimum of two and a maximum of six members on the team.
When you submit the code you can just re-input their names on the form here.
by Davespice
Wed Jan 17, 2018 3:20 pm
Forum: Astro Pi
Topic: How to trigger the camera based on ISS location
Replies: 7
Views: 1263

How to trigger the camera based on ISS location

Hi folks, I recently had a team ask how to do this so I knocked up some code to show the concept; https://gist.github.com/davidhoness/b0e18fa3595d8118d050ce5a9fed68c0 You use two-line element telemetry to calculate ISS position (refresh from http://www.celestrak.com/NORAD/elements/stations.txt) and ...
by Davespice
Wed Jan 17, 2018 3:02 pm
Forum: Astro Pi
Topic: Sense Hat Rubbish temperature accuracy
Replies: 7
Views: 3705

Re: Sense Hat Rubbish temperature accuracy

Yeah we've had some teams base their Astro Pi experiment on calibrating our the error here, some of them have gone to huge lengths to work out how much the CPU load increases it's temperature and all sorts. Because the Sense HATs that went to the Space Station had the fault we decided that everyone ...
by Davespice
Tue Jan 09, 2018 11:23 am
Forum: Astro Pi
Topic: Color in a picture
Replies: 3
Views: 841

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: 988

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: 778

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.

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