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by daveake
Sun Feb 21, 2016 4:00 pm
Forum: Camera board
Topic: Settings for camera in a high altitude balloon scenario
Replies: 4
Views: 626

Re: Settings for camera in a high altitude balloon scenario

Here's the raspistill line I use: raspistill -st -w <width> -h <height> -t 3000 -ex auto -mm matrix -o <filename> With those raspistill does a pretty good job of coping with the rather challenging range of luminence. The latest release of my balloon tracker software allows for extra raspistill setti...
by daveake
Mon Jan 25, 2016 11:51 pm
Forum: High Altitude Balloon
Topic: High altitude internet
Replies: 3
Views: 2290

Re: High altitude internet

Internet from a high altitude balloon is only going to happen with a suitable satellite modem. It'll be slow and/or expensive. Which leads me to .... what is it that you actually want? For the most part, hobby weather balloons just send down position data (telemetry) and perhaps images too. APRS is ...
by daveake
Tue Dec 08, 2015 9:27 am
Forum: General discussion
Topic: Pi Zero Temp Spec ?
Replies: 60
Views: 19348

Re: Pi Zero Temp Spec ?

For someone with over 20 years of embedded engineering experience I am stunned that you are considering building a product based on the Zero. Until last week it didn't exist. Up to now there is very little accumulated experience with it. Oh, and nobody sells them! They are out of stock everywhere. ...
by daveake
Fri Dec 04, 2015 5:43 pm
Forum: General discussion
Topic: Pi Zero Temp Spec ?
Replies: 60
Views: 19348

Re: Pi Zero Temp Spec ?

Whilst officially it's lower limit is -40 (AFAIK) it may be that some of the high altitude balloon guys or penguin monitor guys may have seen temperatures lower than that in real life. As with anything built in to a product, you'll need to test in an environmental chamber as combinations of compone...
by daveake
Mon Nov 30, 2015 3:30 pm
Forum: General discussion
Topic: Raspberry Pi Zero power consumption
Replies: 49
Views: 93531

Re: Raspberry Pi Zero power consumption

I've not managed to go below 66ma ... still nothing near Fluke-grade :-). Any cheap DMM will be an order of magnitude more accurate and precise than the USB tester; you just need to get it inline between power source and Pi. I only mention the Fluke because, after 30 years of cheaper meters, I fina...
by daveake
Mon Nov 30, 2015 3:15 pm
Forum: General discussion
Topic: Raspberry Pi Zero power consumption
Replies: 49
Views: 93531

Re: Raspberry Pi Zero power consumption

Another way of reducing power consumption is to reduce the voltage that the Pi Zero runs from. With HDMI and the LED off, and voltage measured at the Pi GPIO pins (so after the series current meter) I get: 5V: 68.2mA = 341mW 3.3V: 85.9mA = 283mW which is a saving of 17%. Woo :p Remember that if you ...
by daveake
Mon Nov 30, 2015 1:42 pm
Forum: General discussion
Topic: Raspberry Pi Zero power consumption
Replies: 49
Views: 93531

Re: Raspberry Pi Zero power consumption

I concur with Mikerr ... I get:

Pi Zero with no peripherals (no USB, no monitor), serial terminal only. After boot: 87.9mA

HDMI Off: 70.7mA

HDMI and LED Off: 68.1mA

All above measured on a Fluke 179 with 5V applied via GPIO pins.

I trust the Fluke above the USB tester.

Dave
by daveake
Fri Nov 27, 2015 10:38 am
Forum: Off topic discussion
Topic: Is a new Raspberry Pi model coming?
Replies: 265
Views: 42929

Re: Is a new Raspberry Pi model coming?

I bet Dave Akerman is busy buying up lots of PiZeros because they'll be easier to fly on his HABs. One in my hand and 2 on order :-). Just waiting for the USB/HDMI adapters to arrive today so I can check that it works with my software (which it should). The lack of camera port is a real shame for H...
by daveake
Fri Nov 20, 2015 2:51 pm
Forum: Beginners
Topic: Pi in stratosphere.
Replies: 2
Views: 684

Re: Pi in stratosphere.

> 1. Can we use Pi as a GPS tracker, which would send tracking information? > Or it's better to use a standard GPS tracker? And what tracker do you recommend? All trackers use GPS (so they know where they are), and that's the easy part. The key thing is how to get that data down to the ground. Mobil...
by daveake
Fri Nov 20, 2015 2:43 pm
Forum: Astro Pi
Topic: Astro Pi Help
Replies: 1
Views: 1218

Re: Astro Pi Help

> I'm a college student and for a project we are launching a balloon satellite at the end of the month. Did this happen (end of the month is gone)? > I am using a raspberry pi 2 with sense HAT. I'd use an A+ as it requires a lot less power. > The issue I have is how can I do 1 of 2 things > 1. Recor...
by daveake
Tue Jul 14, 2015 1:37 pm
Forum: General discussion
Topic: Optical disc codes
Replies: 14
Views: 2119

Re: Optical disc codes

How much data do you actually have? Even logging everything at 1 second intervals a typical weather balloon flight won't generate more than about 2MB of GPS data and telemetry. Unless you're storing video then I don't see the need for any more storage than a small SD card or USB stick or just cloud ...
by daveake
Fri Jun 26, 2015 9:54 pm
Forum: General discussion
Topic: Questions about High Altitude Balloon Flights
Replies: 52
Views: 4743

Re: Questions about High Altitude Balloon Flights

If a skilled amateur (66 previous flights) can't manage more than 33 days then you won't be able to either (or realistically get anywhere close to even 33 days). Are you talking about Leo Bodnar's B-64 (MOXER-4)? That launched in mid-July 2014 and terminated somewhere over Iceland near the end of N...
by daveake
Thu Jun 11, 2015 3:45 pm
Forum: General discussion
Topic: Questions about High Altitude Balloon Flights
Replies: 52
Views: 4743

Re: Questions about High Altitude Balloon Flights

100 days with a latex balloon? Not happening. Latex degrades. Longest flight I know of with Latex was about 3 days. Generally they pop at the start of the second day. For 100 days you need a plastic balloon, and either a lot of money (£20,000) for a large one, or skill in making your own. You will a...
by daveake
Tue May 05, 2015 8:41 pm
Forum: Other projects
Topic: Was the RPi used in this High Altitude Ballooning Event
Replies: 2
Views: 563

Re: Was the RPi used in this High Altitude Ballooning Event

No, that one didn't use a Pi.
by daveake
Wed Mar 11, 2015 5:04 pm
Forum: General discussion
Topic: RPi - Total Solar Eclipse March 2015
Replies: 6
Views: 1211

Re: RPi - Total Solar Eclipse March 2015

PiGraham wrote:
pluggy wrote:We just need a volunteer to go up inside the Arctic circle so its total.....
Send a Pi on a balloon?
This is happening.
by daveake
Tue Mar 10, 2015 1:28 pm
Forum: General discussion
Topic: Does the Raspberry Pi work in a Vacuum?
Replies: 60
Views: 8956

Re: Does the Raspberry Pi work in a Vacuum?

it does not work in a vacume, the top of our atmostphere is about -40 degrees CELSIUS, if a electronic gets tooooo cold the electricity cannot flow. my go pro froze when it reached the edge in a weather baloon, handwarmers didnt do the trick... but i did keep it in a air tight container. That's the...
by daveake
Wed Mar 04, 2015 5:39 pm
Forum: General discussion
Topic: Does the Raspberry Pi work in a Vacuum?
Replies: 60
Views: 8956

Re: Does the Raspberry Pi work in a Vacuum?

I've flown the Pi about 20 times so far, mostly at around 40km altitude (0.3% atmosphere), and no problems at all other than the SD card coming out of a model A when Babbage's 'chute opened and twisted his neck back! Most flights have been 2-3 hours duration but some have been approx 20 hours. So no...
by daveake
Thu Jun 12, 2014 12:45 pm
Forum: General discussion
Topic: Raspberry Pi Altitude
Replies: 7
Views: 1252

Re: Raspberry Pi Altitude

The Pi works well for high altitude balloon flights. I've flown the Pi about 17 times (I think - I'm starting to lose count), at up to 41km, and have yet to see a component failure of any sort.

Your main concern should be to limit power consumption, rather than worry about electrolytics.
by daveake
Fri May 09, 2014 9:04 pm
Forum: Camera board
Topic: Save and Stream Video?
Replies: 3
Views: 3218

Re: Save and Stream Video?

Yes, what country is this in? You should check that it's actually legal for you to use WiFi frequencies/powers from an airborne device. Also you'd probably get better results using ATV transmitters and receivers, again depending on legality. This is done a lot in the USA where it's legal with even a...
by daveake
Tue Apr 29, 2014 3:43 pm
Forum: HATs and other add-ons
Topic: GPS flight mode?
Replies: 2
Views: 2402

Re: GPS flight mode?

You need to send a binary command in UBX format. You can get the exact command from the UBlox manual, or by using U-Center and inspecting the commands, or more simply by having a look at the source code here: http://ukhas.org.uk/guides:ublox6 That's for an Arduino, in C, but all you need is to grab ...
by daveake
Mon Apr 07, 2014 11:44 am
Forum: Beginners
Topic: Can the RPi be powered by 3.3V only?
Replies: 17
Views: 3127

Re: Can the RPi be powered by 3.3V only?

Yes you can apparently. It involves removing the 5v regulator, fooling the power pin on the bcm and voiding your warrantee, but I did read a how to do it. I'm looking at solar power and it's one of the ways to cut down power consumption. You can even run USB peripherals if they will run of of 3.3v ...
by daveake
Mon Apr 07, 2014 11:41 am
Forum: Beginners
Topic: Can the RPi be powered by 3.3V only?
Replies: 17
Views: 3127

Re: Can the RPi be powered by 3.3V only?

This question is being answered with to many IFFs or BUTTs The Pi was designed to to work with a regulated 5vdc in/put The on board regulator stepped the 5v down to give you 3.3v for the GPIO in/puts & out/puts to interface with your Projects. Back feeding the Pi causes to many problems. The Pi was...
by daveake
Thu Mar 06, 2014 11:11 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Two devices connected to a single UART
Replies: 27
Views: 9838

Re: Two devices connected to a single UART

My first 4 Pi weather balloon flights all used this method - separating Tx/Rx for NTX2 and GPS. The first flight used a Lassen GPS which doesn't need to be sent to, but after that I used UBlox devices which do- they *have* to be put into "flight mode" otherwise they stop working above 18km. For thos...
by daveake
Mon Feb 24, 2014 4:36 pm
Forum: Other projects
Topic: Pi Near Space
Replies: 6
Views: 1555

Re: Pi Near Space

Me and have friend have had an idea for several months:Launch a Pi as close to space as we can. Solid rocket booster, though they would get us higher, post several threats and cost issues. We have decided upon several helium filled balloons lifting a Pi and several sensors and cameras up to about 2...
by daveake
Sun Feb 23, 2014 9:52 pm
Forum: Other projects
Topic: Pitellite - A Raspberry Pi based satellite
Replies: 7
Views: 3234

Re: Pitellite - A Raspberry Pi based satellite

The OP is basically describing The Register's LOHAN project . Well, despite the name, LOHAN (which I have something to do with) won't reach orbit. It's just a plane with a tiddly rocket motor. A lot of the stuff for LOHAN has been donated, but if it hadn't £3000 certainly wouldn't cover the cost of...

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