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by daveake
Sun Jan 26, 2014 5:13 pm
Forum: General discussion
Topic: Crash recovery on a raspberry pi
Replies: 9
Views: 3232

Re: Crash recovery on a raspberry pi

In the UK the best system by far is a UHF radio link, because you'll then have 10-20 other people receiving your balloon telemetry. Go read the wiki at http://www.ukhas.org.uk and then join us in the IRC chatroom #highaltitude on freenode.
by daveake
Sun Jan 26, 2014 5:10 pm
Forum: Other projects
Topic: High Altitude Balloon Tracker
Replies: 6
Views: 5231

Re: High Altitude Balloon Tracker

Search for SSDV on github
by daveake
Sun Jan 26, 2014 5:09 pm
Forum: Camera board
Topic: Possible to stream video over RF?
Replies: 3
Views: 1934

Re: Possible to stream video over RF?

Yeah, video needs lots of bandwidth and that means lots of power which, in the UK, we're not allowed to use. This has been done in other countries with less restrictive rules.
by daveake
Fri Jan 17, 2014 9:41 am
Forum: General discussion
Topic: How much power will my pi use?
Replies: 5
Views: 1311

Re: How much power will my pi use?

Oh, and to answer your question about power consumption, measure it I can give you approx figures but the exact ones depend on what your software is doing - in particular what use you're making of the camera. If you're taking a lot of video then it'll be much much higher than if you're just taking a...
by daveake
Fri Jan 17, 2014 9:38 am
Forum: General discussion
Topic: How much power will my pi use?
Replies: 5
Views: 1311

Re: How much power will my pi use?

First, why the limit of 250g? Though it's entirely possible to build a Pi camera payload in a lot less than that (about half), many flights have payloads in the 500g - 1kg range. Unless you want the flight to get particularly high, or you're trying to save money by using a small balloon, or you're p...
by daveake
Fri Jan 17, 2014 9:30 am
Forum: General discussion
Topic: Crash recovery on a raspberry pi
Replies: 9
Views: 3232

Re: Crash recovery on a raspberry pi

...mobile modem dongle.. I should have picked up on this before. If the modem dongle is your only means of locating the weather balloon, expect to lose it. GSM coverage is far from 100% and, depending on where you expect it to land, there's a pretty good chance of you never seeing your payload agai...
by daveake
Fri Jan 17, 2014 9:27 am
Forum: General discussion
Topic: Crash recovery on a raspberry pi
Replies: 9
Views: 3232

Re: Crash recovery on a raspberry pi

In my opinion you're trying to fix a problem that doesn't (or shouldn't exist). I've flow the Pi under a weather balloon 13 times now, including some long duration flights, and the Pi hasn't hung up once. The only issues were that on one flight the SD card came loose, and on another the cutdown circ...
by daveake
Tue Nov 19, 2013 8:13 pm
Forum: Advanced users
Topic: Running Raspberry on 3.3 V
Replies: 33
Views: 22006

Re: Running Raspberry on 3.3 V

OK, well obviously the keyboard and mouse won't be flying, so test again without those! Also, the GPS will draw a lot more current before it acquires a lock than when it does after. I don't fly the GPS/GSM trackers anymore. I did use one twice as backup, and it worked one of those 2 flights. Briefly...
by daveake
Sun Nov 17, 2013 1:28 pm
Forum: Advanced users
Topic: Running Raspberry on 3.3 V
Replies: 33
Views: 22006

Re: Running Raspberry on 3.3 V

If your model A Pi is drawing 400mA, something is wrong. Perhaps a bad DMM. It should be around 115mA. I tried a few things to reduce that, and the only noticeable power reduction was to switch off the video output. On top of that, you'll need around 80mA for the radio and GPS, so total for the trac...
by daveake
Wed Nov 13, 2013 11:53 pm
Forum: Other projects
Topic: Removing DSI diplay connector?
Replies: 14
Views: 3560

Re: Removing DSI diplay connector?

The answer to the connector question is "yes", it has been done, by Dave Ackerman (of pi-in-the-sky fame), in order to fit 4 AA batteries into a standard R-Pi case. I am almost sure he started with the Model A, though. One approach is to first simply cut off most of it with sidecutter shears (caref...
by daveake
Wed Nov 13, 2013 4:15 pm
Forum: Advanced users
Topic: Running Raspberry on 3.3 V
Replies: 33
Views: 22006

Re: Running Raspberry on 3.3 V

By far and away the best option for stopping any overheating in a weather balloon payload is to not generate the heat in the first place, and for a Pi tracker that means using a model A. Average consumption will then be around the 200mA mark for the entire tracker, except for during any video record...
by daveake
Thu Nov 07, 2013 3:22 pm
Forum: Advanced users
Topic: Running Raspberry on 3.3 V
Replies: 33
Views: 22006

Re: Running Raspberry on 3.3 V

Yes you can do that. Personally I remove the LDO anyway. A switcher can be more efficient than an LDO but it weighs more and will likely have a higher dropout voltage than the LDO that I use, so you'll need more batteries. I suggest you do the maths to see what's best for you (see my article linked ...
by daveake
Wed Nov 06, 2013 9:52 pm
Forum: Advanced users
Topic: Running Raspberry on 3.3 V
Replies: 33
Views: 22006

Re: Running Raspberry on 3.3 V

according to Dave Akerman 5V for the SoC is only needed for A battery sense pin on the BCM2835 That came from Eben, though there's every possibility that what I thought he said wasn't what he actually said :-) I've run many model A's from 3.3V applied to the 3.3 and 5V lines - several balloon track...
by daveake
Mon Oct 07, 2013 7:32 pm
Forum: Camera board
Topic: Camera causing interference to GPS
Replies: 9
Views: 4279

Re: Camera causing interference to GPS

I'm surprised that they would be considered an advantage though- I have read the helix advantage is that the GPS still works with the antenna in any orientation, while the typical ceramic patch antenna wants to be pointing upwards. But I'd think that means it picks up interference from any directio...
by daveake
Thu Oct 03, 2013 8:48 pm
Forum: Camera board
Topic: Camera causing interference to GPS
Replies: 9
Views: 4279

Re: Camera causing interference to GPS

Dave Akerman ( http://www.daveakerman.com/ ) has used a Pi, PiCam, GPS receiver, Transmitter, etc in a small payload for his high Altitude Balloon. Perhaps he can tell us if he did anything special. One of my flights (the Babbage one) lost GPS lock when the camera was in video mode. The rest of the...
by daveake
Thu Oct 03, 2013 8:42 pm
Forum: Other projects
Topic: Space Raspberry Pi
Replies: 7
Views: 2042

Re: Space Raspberry Pi

Maybe you can use a normal 3g dongle and receive the cordinate only when it land back to earth... You can't follow the flight live, but you can find your raspberry once landed... You can do that, however there's a rather high probability that it will land somewhere outside GSM coverage, in which ca...
by daveake
Thu Oct 03, 2013 8:39 pm
Forum: Automation, sensing and robotics
Topic: Absolute Pressure Transducer / Altimeter
Replies: 3
Views: 4060

Re: Absolute Pressure Transducer / Altimeter

GPS is the best bet. Pressure transducers that will give a reading below 1% atmosphere (which is what you get at about 30km) are not cheap.

It's possible for flights to get up beyond 40km. I use UBlox modules which can be put into a flight mode so they work up to 50km.

Dave
by daveake
Thu Oct 03, 2013 8:35 pm
Forum: Camera board
Topic: Metering modes
Replies: 8
Views: 3060

Re: Metering modes

Dave Akermans first HA balloon flight with the Pi used matrix I think and the pictures at high altitude were a bit pants for exactly this reason. Switching to average worked a treat. Actually I switched *to* matrix from [whatever the default is - spot I was told]. "space" images are a bit tricky be...
by daveake
Sat Sep 14, 2013 4:15 pm
Forum: Español
Topic: Need Radio Listeners
Replies: 1
Views: 456

Need Radio Listeners

Raspberry Pi "Space" Flight: Este lunes 16 de septiembre a las 2 de la tarde el equipo http://www.theregister.co.uk/Wrap/lohan (Low Orbit Helium Assisted Navigator) lanzará un globo meteorológico cerca de Piedrahita (Avila) Necesitamos la ayuda de los radioaficiondos españoles y portugueses para rec...
by daveake
Thu Sep 05, 2013 3:37 pm
Forum: Other projects
Topic: Space Raspberry Pi
Replies: 7
Views: 2042

Re: Space Raspberry Pi

Most TV tuner dongles will do it. See http://ukhas.org.uk/guides:sdr_tracker for more info.
by daveake
Fri Aug 30, 2013 6:02 pm
Forum: Other projects
Topic: Space Raspberry Pi
Replies: 7
Views: 2042

Re: Space Raspberry Pi

I very strongly suggest you go and read the wiki at www.ukhas.org.uk. That explains how to connect to the NTX2 and how to receive on the ground, plus lots and lots of other things you will need to know to make your mission a success.

Dave
by daveake
Mon Apr 15, 2013 8:24 am
Forum: User groups and events
Topic: 2nd Egham Raspberry Jam - 14th April 2013
Replies: 42
Views: 7650

Re: 2nd Egham Raspberry Jam - 14th April 2013

Sorry again that I couldn't come along. I was really hoping to make this but after the previous day's shenanigans and staying up most of the night watching a map, I was just too tired and slept most of the afternoon!
by daveake
Thu Mar 21, 2013 6:02 pm
Forum: General discussion
Topic: Time lapse with a Webcam
Replies: 10
Views: 13981

Re: Time lapse with a Webcam

Just write a loop in a shell script or the language of your choice, taking a photo each time round, and waiting for n seconds between shots. The filename will need to change e.g. file0001.jpg, file0002.jpg etc. I used fswebcam to take the shots but other programs are available.
by daveake
Wed Mar 20, 2013 5:08 pm
Forum: Off topic discussion
Topic: Logitech Webcam C270 is not working with raspberry pi
Replies: 4
Views: 16771

Re: Logitech Webcam C270 is not working with raspberry pi

That model works for me, using Raspbian on an early board with the USB fuse shorted. As above try with a powered hub. My experience with the this webcam (and others) on the early board with fuses was that it would appear OK as /dev/video0, and I could take small photos with it, but large photos or v...
by daveake
Wed Mar 13, 2013 5:48 pm
Forum: General discussion
Topic: Time lapse with normal camera
Replies: 1
Views: 442

Re: Time lapse with normal camera

Not with those ports, no. If you need the images to get to the Pi, for upload or whatever, then take a look at "PTP" (Picture Transfer Protocol), using the USB port to control the camera and grab image files. If all you want to do is automate the picture-taking, then you can use the GPIO pins to con...

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