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by daveake
Mon Mar 11, 2013 10:59 am
Forum: Automation, sensing and robotics
Topic: Parachute release
Replies: 4
Views: 1622

Re: Parachute release

Yeah, don't do it like that! The rocket guys use releasable parachutes all the time, but if a deployment fails (and they do) the rocket destroys itself into the ground near the launch site. I've seen a video of this happening and it made a pretty big hole in the ground. With a balloon the landing sp...
by daveake
Mon Feb 25, 2013 12:36 pm
Forum: Graphics, sound and multimedia
Topic: convert image to rtty
Replies: 6
Views: 2624

Re: convert image to rtty

Generally you will find those people are licensed radio amateurs In the UK and some other countries radio amateurs are not allowed to use their licence from an airborne device, so we are restricted to using licence-free transmitters in some small, low-power bands where airborne use is permitted. Th...
by daveake
Tue Feb 12, 2013 11:06 pm
Forum: Troubleshooting
Topic: GPIO - UART - Getting Weird Serial Output... Stumped...
Replies: 6
Views: 4833

Re: GPIO - UART - Getting Weird Serial Output... Stumped...

First thing I'd do is to get that baud rate down, on both ends of course, to something more reasonable. 115,200 baud is going to be a bit of a push for the software UART on the Uno, particularly as it will also be servicing h/w interrupts for the real UART. Try 9600 and work up. At a guess 38,400 wi...
by daveake
Tue Feb 12, 2013 9:35 pm
Forum: Camera board
Topic: STICKY: Foundation (old) Camera Board information
Replies: 446
Views: 293022

Re: Foundation Camera Board information

jamesh wrote:More information. Just weighed the module...
  • PCB+Camera module 2.4g
    RIbbon cable 1.0g
So all up weight is 3.4g - should make it a good options for balloon flights.
Ah thanks, excellent low number :D
by daveake
Fri Feb 08, 2013 11:51 pm
Forum: Advanced users
Topic: Model A: How low can you go? (Power consumption)
Replies: 34
Views: 21617

Re: Model A: How low can you go? (Power consumption)

pygmy_giant wrote:can someone summarise that for us simpletons?
Model A uses about 1/3rd the power that the model B uses.

Underclocking makes next to no difference.

To save more power replace the on-board linear 3.3V regulator with a switching one.
by daveake
Mon Feb 04, 2013 8:36 pm
Forum: General discussion
Topic: Is Raspberry Pi becoming like DeLorean DMC-12?
Replies: 11
Views: 2149

Re: Is Raspberry Pi becoming like DeLorean DMC-12?

NewAtlantis wrote:Stuff
No, it's all a cunning plan to prevent you from buying a Pi, in order to save the rest of us from the troll-tastic questions you'll come up with when you get your hands on one.
by daveake
Fri Feb 01, 2013 4:59 pm
Forum: C/C++
Topic: UART receive problem
Replies: 11
Views: 15607

Re: UART receive problem

Then you need to send something from the PC to the RPi. That code is simply reporting that it sees no data. It's not an error.

If you can, rewrite the code so it sits in a loop waiting for incoming data, and displays it when it sees it.

Dave
by daveake
Fri Feb 01, 2013 4:05 pm
Forum: C/C++
Topic: UART receive problem
Replies: 11
Views: 15607

Re: UART receive problem

Have you connected the port to something? If so do you know that the baud rate etc. in that code match the device you've connected it to? Are you sure that the other device is sending something? That code simply sends a short message and then looks, once, for some incoming data. To test that the por...
by daveake
Fri Jan 25, 2013 9:40 pm
Forum: General discussion
Topic: STICKY: Introduce yourself!
Replies: 3546
Views: 115415

Re: Introduce yourself!

Hi all. I'm Dave Akerman, "Pi In The Sky" guy. A child of the 60's I watched the Apollo missions in awe and assumed that by now we'd have a permanent base on the moon and have men on Mars. I'm a keen photographer, so when in Feb 2011 I saw a Youtube video showing 2 guys put a foam box into "space" t...
by daveake
Thu Jan 24, 2013 3:39 pm
Forum: General discussion
Topic: One PSU for Pi, WebCam, Wifi and 12v Motor
Replies: 12
Views: 9815

Re: One PSU for Pi, WebCam, Wifi and 12v Motor

Yes, it'll have 5V, 12V and GND in the PS/2 plug. Just be very very careful that you connect the right micro-USB wires to the right PS/2 pins to avoid having an ex-Pi on your desk :)
by daveake
Thu Jan 24, 2013 2:06 pm
Forum: General discussion
Topic: One PSU for Pi, WebCam, Wifi and 12v Motor
Replies: 12
Views: 9815

Re: One PSU for Pi, WebCam, Wifi and 12v Motor

It wouldn't take long to knock up an adapter with a PS/2 socket at one end and a micro-USB at the other, plus whatever connector you need for your 12V motor. Personally I'd just grab a USB-micro USB lead, remove the USB end, and solder it to an inline PS/2 socket. If you're hoping to buy something w...
by daveake
Thu Jan 24, 2013 12:27 pm
Forum: General discussion
Topic: One PSU for Pi, WebCam, Wifi and 12v Motor
Replies: 12
Views: 9815

Re: One PSU for Pi, WebCam, Wifi and 12v Motor

Many external hard drives have (or used to have - seems less common these days) dual-voltage power supplies. I just searched on ebay for "5V 12V PSU" and this was the first possible one that came up: http://www.ebay.co.uk/itm/6-PINS-HDD-HD-12V-5V-DC-AC-PSU-Power-Supply-Adapter-UK-/270724572565?pt=UK...
by daveake
Tue Jan 22, 2013 11:11 pm
Forum: Other projects
Topic: powering the Pi through the audio jack? NO!!!
Replies: 21
Views: 4023

Re: powering the Pi through the audio jack!?!?!?

"Creative" as in likely to create a broken Pi. You're applying 5V to a pin that has a protection diode to the 3.3V rail. A diode with an Imax of 125mA, and a Vf of around 1V at the sort of current it'll be passing. So you're going to over-voltage the 3.3V rail, meaning that exceeding the diode's Ima...
by daveake
Tue Jan 22, 2013 5:43 pm
Forum: Debian
Topic: freeing the uart port
Replies: 9
Views: 1910

Re: freeing the uart port

All the pins you need to connect to are listed in the GPIO section of the RPi wiki:

http://elinux.org/RPi_Low-level_peripherals

Dave
by daveake
Tue Jan 22, 2013 2:04 pm
Forum: General discussion
Topic: Software Monitoring of Supply Voltage and CPU Temperature
Replies: 5
Views: 51715

Re: Software Monitoring of Supply Voltage and CPU Temperatur

The temperature is easy enough - run this:

/opt/vc/bin/vcgencmd measure_temp

For the supply voltage AFAIK you'll have to add an A/D. That's what I do for my weather balloon tracker. In that I monitor the battery voltage but it could very easily be changed to modify the 5V rail or whatever.

Dave
by daveake
Mon Jan 21, 2013 10:44 pm
Forum: User groups and events
Topic: Egham/Staines - 20th January 2013 - 2:00pm - 5:00pm
Replies: 32
Views: 5831

Re: Egham/Staines - 20th January 2013 - 2:00pm - 5:00pm

I've uploaded my Pi In The Sky slide presentation in case anyone's interested.
by daveake
Wed Jan 16, 2013 1:26 pm
Forum: Beginners
Topic: I have an 8GB SD Card, but only getting 4GB
Replies: 6
Views: 7455

Re: I have an 8GB SD Card, but only getting 4GB

If you're using Rapbian, just run raspi-config and choose the option to use the entire SD card. See http://learn.adafruit.com/adafruits-ras ... n/overview for example.
by daveake
Wed Jan 16, 2013 1:15 pm
Forum: Automation, sensing and robotics
Topic: Starting with project to read in data from multiple sensors
Replies: 3
Views: 1106

Re: Starting with project to read in data from multiple sens

For temperature I use the DS18B20 one-wire sensor, supported by the w1_therm module. Once the module is loaded you can get the temperature by opening/reading a file - very easy in any language.
by daveake
Tue Jan 15, 2013 9:54 pm
Forum: Automation, sensing and robotics
Topic: QuirkyKepler Space module DIY
Replies: 4
Views: 1322

Re: QuirkyKepler Space module DIY

The Stratosphere has a habit of breaking things that you thought were well designed. Things like stepper motors and solenoids may well freeze up. A Raspberry Pi controller may fail because the SD card comes loose. I would not want to rely on anything not 100% reliable to deploy a parachute, nor woul...
by daveake
Mon Jan 07, 2013 5:32 pm
Forum: Debian
Topic: freeing the uart port
Replies: 9
Views: 1910

Re: freeing the uart port

You connect GND and GND together, Tx to Rx, and Rx to Tx. I don't know how much power the Propellor board takes, but if it's 3.3V at no more than 50mA then you can connect 3.3V from the Pi to the 3.3V line on the Propellor. For low-level "send a byte" stuff, you don't need any special library. In 'C...
by daveake
Tue Jan 01, 2013 7:23 pm
Forum: User groups and events
Topic: Egham/Staines - 20th January 2013 - 2:00pm - 5:00pm
Replies: 32
Views: 5831

Re: Egham/Staines - 20th January 2013 - 2:00pm - 5:00pm

I'll bring along my "Pi In The Sky" radio tracker from http://www.daveakerman.com/?p=592. Hoping to launch again around the end of January.

Dave
by daveake
Thu Dec 27, 2012 9:16 am
Forum: General programming discussion
Topic: RP for video and temp / pressure messuring
Replies: 4
Views: 1463

Re: RP for video and temp / pressure messuring

A few points ... First, find out what power/frequency you can legally transmit in your country "from an airborne vehicle", and whether you need a licence to do so. In the UK for example we are severely limited by our laws, and we use 10mW UHF signals. That power is *not* enough to do a live video li...
by daveake
Tue Aug 28, 2012 11:15 am
Forum: Other projects
Topic: Pi in space!
Replies: 5
Views: 1439

Re: Pi in space!

Your best bet is to go and read the wiki at www.ukhas.org.uk. Lots of useful info there about all aspects of flying weather balloons, including parachute deployment. Pretty much every flight has the parachute inline with the balloon. i.e. Balloon -----> Parachute ----> Payload. That way you aren't r...
by daveake
Tue Jul 17, 2012 11:24 pm
Forum: Troubleshooting
Topic: operation in extreme environments
Replies: 15
Views: 3179

Re: operation in extreme environments

Out of curiosity, how long does it take to beam each (low-res) image back to ground? Between 3.5 and 5 minutes each one - a bit better than I was expecting. The images are all jpeg compressed and that makes short work of black sky :-). You can see the full set on the site that they got uploaded to ...
by daveake
Tue Jul 17, 2012 10:51 pm
Forum: General discussion
Topic: News articles and blog posts about Raspberry Pi
Replies: 1021
Views: 201937

Re: News articles and blog posts about Raspberry Pi

http://www.theregister.co.uk/2012/07/17/pi_ascent/ Eben will be pleased - he doesn't have to eat his hat now ;). Yes, someone linked me to that quote the night before my flight. Glad to be of service! There's a fantastic amount of detail in the writeup :D http://www.daveakerman.com/?p=592 Thanks! T...

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