HAB Balloon Inflation

After some initial rookie mistakes I now may have a working balloon inflator. I mistakenly purchased online a filler kit of which the regulator was not the required Type 10 for Australian gas cylinders, so of course when my gas cylinder arrived this morning the regulator wouldn't fit. With little time remaining I hit the web and found several places that I wish I had found earlier.

Conwin’s Inflator

Several party balloon places provide filling implements for balloons they call cloud busters. A company in Sydney Qualtex distributes an inflator but only sells through its distributors. If you have the time you may be able to ask your local part shop if they can order one for you.

I didn't want to wait for an order to be placed so I decided to make my own inflator, with the nozzle I already had. I just needed to find a new regulator.

I was stuck trying to decide on which regulator would be the easiest to modify for my purpose.

I could have opted for the standard balloon inflator pictured on the right, but I wasn't sure if I would be able to find a brass fitting with a hose nipple in time, But I'm sure this would have worked Also I'm uncertain as to what the flow rate would be.

I finally decided on a regulator that had a variable flow rate and dials, I was able to connect a hose to the provided nozzle and onto my inflator nozzle.

My setup

Filler nozzle fits the balloon

The setup looks good, but honestly I'm not confident as its a little off what I was after.  The nozzle on the regulator was for only a 5mm hose, so I don't know if this will give a great flow rate. I also hope that the hose will be durable enough not to burst. I'm sure I will find out soon.

I also pulled my balloon out of its bag to ensure that the filler nozzle actually was the right size for my balloon.  Thankfully it fitted perfectly.

Time Fly's

With work, family and other commitments taking priority and even the odd flood in Central NSW, I've forgotten how long ago it was when I began this project. Too long.

With only a week or so left of my holiday leave I have decided to make a final push to get the launch underway. I've spent the last few days running flight predictions in order to find a suitable launch location. I want to keep the balloon from landing in any dense forested areas on the East Coasr, as well as keeping it away from any populated areas.

I've also been running around picking up last minute supplies which included a regulator and filler hose which will hopefully do the job.

Fingers crossed at the moment that all goes to plan

High Altitude Baloons

Thought I would look into some of various High Altitude Balloon available on the market to hopefully help me decide what I need to obtain.

My initial reading tells me I need a balloon capable of lifting my weighted payload high into the upper atmosphere. Getting the wrong balloon could lead to a low altitude burst and spoil the fun early.

I have seen a number of other HAB projects use Hwoyee Balloons but I'm sure there are many others.

Other sites :-

Kaymont Balloons - Totex Balloons


Several of the balloon websites sell different styles of balloons. Most designed for meteorigolical purposes.

Ceiling Balloons - Smaller compared to other weather balloons and is usually use to measure cloud height.
Pilot Balloons - Are usually used to measure wind speed and direction. Usually rise to 15,000 - 40,000 feet depending on the ascent rate and payload.
Sounding Balloons - These are the larger of the weather style balloons and have been known to reach heights in excess of 130,000 feet.

Kaymont Balloons suggest several balloons on their website. Such as HAB-600 for first time HAB'ers up to the HAB-3000 for higher burst altitudes.

APRS Tracking

After some minor hurdles I now seem to have my OpenTracker USB working correctly. So I am a lot closer to having a tracker ready for extreme testing.

Current setup contains a Garmin GPS-18x-PC connected directly into the Open Tracker via the serial connector. The Open Tracker then connects into a Yaesu VX-7R handheld.   The GPS and Tracker are connected to a bank of AA Batteries supplying 12volts, whilst the handheld uses its own battery.

Initial tests have been using the same AA's for several months with tests over that time being for several hours. I have been monitoring the voltage over this time dropping from 12volts , down to 9 volts and this morning on a drive to work , the voltage was at 7 volts. All the while the tracker and GPS were still operating. I am still only using standard AA's so nothing like what will be in the final version, but so far happy that the battery should last the trip.  I do hope to connect a few more devices up to the same power source such as a data logger, so this may test this power supply some more.

I have also discovered that the GPS seems to take time to obtain a GPS fix, this seems to add delay to the initial transmission. I need to nut this out further to ensure that it is just a GPS visibility problem as when the GPS was in clear view of the sky I couldn't reproduce the problem.  But want to ensure all is good for launch day otherwise its a waste of battery power waiting for a GPS fix before launch.

Opentracker USB take 2

After damaging the original radio mic cable that came with my tracker, I was starting to think that I may have damaged something in the tracker itself. Nothing I tried seemed to make the tracker key up my handheld. However, a couple of days ago my replacement mic cable arrived and I finally found some time to play with it.

Initially I wired up the cables as per the original , however nothing worked. I discovered that the mic cable was wired differently and needed to swap a few cables around. This seemed to do the trick and I am now TXing again. Phew...

Now that I am TXing again, I haven't yet seem my callsign appear on aprs.fi So again I was wondering if something wasn't right. So to test this out I downloaded some APRS tracking software that runs using  my PC's soundcard. After a few tweaks, like changing the baud rate to 1200, i had success. The application decoded my handhelds signal and I was able to read the coordinates. It accurate to about 5 meters, which probably isn't to bad seeing the GPS unit is on the window and probably not seeing a full sky.

So with a big smile on my face, I can finally after many weeks of downtime move on to get the tracker into a more portable form. Would be nice to see my callsign on APRS.fi to double confirm that everything is ok.

Open Tracker USB

Decided to purchase an Open Tracker USB APRS tracker and over the past few weeks have been playing around with it. I initially purchased the tracker by itself, but after ordering decided to also purchase the adaptor cable to connect into my Yaesu 7R handheld.  So wasted a week waiting.  I could have made my own cable, but really wasn't in the mood.

Open Tracker USB comes with a few different options for power, I decided to order it with the cig lighter as I could cut it off and connect a battery power source.

To configure the device you plug in a USB cable and run the provided configuration tool. It is very easy to configure with an example config that I used on www.aprs.net.au

When using the USB cable your computer will power the tracker. However for the first test I connected the tracker to a 12v DC power supply and hooked my Garmin 18x PC GPS up. Straight away I could see blinking lights but didn't really know what they meant at the time. So assumed things were ok.

Later when I received the correct cable for the vx-7r I was able to see that the vx-7r was sending out a signal. Though it was sending something I still didn't know if it was working. My call wasn't appearing on any APRS maps, but I'm hoping this is because my handheld is unable to get a decent signal out.

Made up a 12v DC battery pack with AA's and connected it up to power the GPS and tracker. All looks good. Decided to take the tracker for a walk to see if a change in location would get a better signal out. However on packing it, I must have damaged the mic cable as I no longer get any transmit.  Damn....
I can see the trackers red light solidly lit , when trying to transmit, but no TX on the radio.

Currently pulling the connector apart to see if I can revive it, otherwise I'll have to purchase another plug. Almost melted the thing with the hot iron. My soldering skills unfortunately are lacking good experience. Anyway we'll see what happens.

CHDK coding on my IXY Digital 70

Decided to have a play around with CHDK scripts available for my camera, and saw that the coding was very easy to follow. So I decided to create my own using some minor pieces from the example scripts provided on the CHDK wiki.

CHDK Screen

I wanted a script that would continuously take photo's for the duration of the flight and would require minimal fiddling around to start. By this I wanted to reduce/remove  any button clicks that may result in a setting being changed pre-launch that could jeopardize the mission.

Below is the code I have started with. It has the following features.  Note that it works with my Canon IXY Digital 70 and may not suit all camera's.

• Sets a 1st shot delay. No point going all snap happy with the box still on the ground.
• Variable shot interval
• Logging of camera internal temperature and battery voltage to SD card.
• Saw this as a backup temp data logger for the flight
• Disable flash.
• Couldn't find a single command for this so had to create a loop that pressed the flash button until it was off.
• Disables LCD screen.
• Read in the script manual, that the screen automatically resumes when you take a picture. For the screen to be turned off you must also allow for the picture to be written to SD card otherwise the screen will just come back on again. I saw this happening so added the 'sleep 500' to give it enough time to save.

Happy for any comments and tips, as its my first CHDK script so I'm sure there may be improvements I can make.


<davCam.bas>


@title DavCam
@param a interval (sec)
@default a 12
@param d Delay 1st Shot (sec)
@default d 20
@param n fileNum
@default n 1

if a<5 then a=5
a=a*1000
if d<1 then d=1
d=d*1000

print "Script will run"
print "until interrupted"
gosub "disFlash"
playsound 1 
sleep d
cls

print_screen n
print get_time 4;"/";get_time 3;"/";get_time 5;" ";get_time 2;":";get_time 1;":";get_time 0
print " "
print "Time,Optics Temp,CCD Temp,BattmV"

o = get_day_seconds

:main
    gosub "getData"
    gosub "takePic"
    set_backlight 0
    sleep a
    rem set_backlight 1
goto "main"

:takePic
    set_zoom 0
    do
        get_zoom z
    until z = 0
    shoot
    sleep 500
    return

:getData
    print (get_day_seconds - o);",";get_temperature 0;",";get_temperature 1;",";get_vbatt;
    return

:disFlash
    f=get_flash_mode
    while f<1
    click "right"
f=get_flash_mode
sleep 500
    wend
    print get_flash_mode
    return

:restore
    set_backlight 1
    end

So far I have set the camera to launch the script when powered on. So hopefully when the launch commences its a matter of pressing one button and that's it.

I haven't looked into exposure settings yet, as I don't really know what will be best for high altitudes. So maybe people reading this may have some ideas.