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Forum Index : Microcontroller and PC projects : Micromite Fly’s Again
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| edu001 Regular Member  Joined: 14/07/2014 Location: United KingdomPosts: 82 |
Hi I am launching another Micromite based HAB (Balloon) tomorrow at about 1030 hours from Birmingham in the UK It will be an endurance flight lasting about 3/4 days on a single 3000Mah AA Lithium Battery, the flight path is predicted to go east over Europe possibly reaching Poland the expected altitude is around 8,000m The MPU is a 44 pin PIC32MX170 with a UBLOX MAX8Q module providing the GPS Data, there is also a PCF8563 RTC on board which completely shuts down the PIC when it's not transmitting, in sleep mode the tracker uses around 10Ma, it wakes and transmits an RTTY String at 100 Baud 2 stop bits and no Parity every 2 mins during daylight hours and every 10 mins during darkness Since the last flight over a year ago the code has been extensively modified, it now queries the GPS module status and sets the power and tracking mode according to the conditions number of satellites altitude etc, this has major power saving implications, (the status is also included in the TX string) There was also a problem with the RTC crystal becoming unstable for no apparent reason which meant that the MPU failed to WAKE which is pretty terminal at 10,000m this was eventually solved by using higher quality resistors and a good quality (expensive) crystal I have tested it down to -38 over long periods with no problems The live tracking data for the payload will be available here https://tracker.habhub.org/#!mt=roadmap&mz=11&qm=1_day&f=EDUPIC16 The callsign is EDUPIC16 If all goes well it should be a good flight but there are no guarantees there is a lot to go wrong!!!! |
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| WhiteWizzard Guru  Joined: 05/04/2013 Location: United KingdomPosts: 2794 |
Exciting times ahead with Robin's MicroMite aiming across the seas, and Jeds heading into space!! Bet Geoff never thought his MicroMite design would be doing these kinds of things . . . . Has anyone sent one 'diving' under water yet? Hopefully not yours Robin  For everything Micromite visit micromite.org Direct Email: whitewizzard@micromite.o |
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9083 |
Especially when you take into account that the MicroMite was just an 'Experiment' by Geoff, to see if he could squeeze the MaxiMite interpreter into a single low-cost DIL chip without the VGA output etc, and I think it is fair to say that the MicroMite series has well exceeded the MaxiMite interest, and I also had the B/W MaxiMite and also the colour MaxiMite. ...but I digress - sorry edu001..... Smoke makes things work. When the smoke gets out, it stops! |
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| Octatron Newbie  Joined: 01/04/2015 Location: United KingdomPosts: 23 |
Jed, How about some more info and photos of your balloon and instrumentation. I was going to say so I can spot it as it passes over my house, but an hour ago it seemed stationary over Aldridge but now it's shot a couple of miles north of my house in Sutton Coldfield and is now over Leicester. A wind must have sprung up. |
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| edu001 Regular Member Joined: 14/07/2014 Location: United KingdomPosts: 82 |
Hi Octatron I will post all the data and some images after the flight with more detail on the build I am busy soldering up and testing a version which charges the battery with tiny solar panels possibly for the next flight |
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| edu001 Regular Member Joined: 14/07/2014 Location: United KingdomPosts: 82 |
EDUPIC16 is happily floating over Belgium at 7300mtrs at a temp of -36C it's looking quite stable at the moment TX'ing bang on time, the Micromite is totally open to the atmosphere with only a coating of PCM lacquer to stop moisture ingress impressive!! Great work Geoff and thanks to WW for your input and assistance |
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| WhiteWizzard Guru Joined: 05/04/2013 Location: United KingdomPosts: 2794 |
A pleasure to be of assistance; and even more so on exciting projects like this one. By the way, your next batch of PCBs have passed the PCB's house checking procedure :-) Keeping a keen eye on this flight. Battery voltage looking good . . . For everything Micromite visit micromite.org Direct Email: whitewizzard@micromite.o |
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Geoffg Guru Joined: 06/06/2011 Location: AustraliaPosts: 3167 |
Great project. It is so impressive that the little fellow is travelling so far. I'm following its progress with interest. Geoff Geoff Graham - http://geoffg.net |
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| Henk Newbie Joined: 06/10/2015 Location: NetherlandsPosts: 20 |
Looks like the balloon is in trouble? Last update 15 hours ago. |
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| WhiteWizzard Guru Joined: 05/04/2013 Location: United KingdomPosts: 2794 |
Jed has taught me a lot about this fascinating hobby and I will try and part with a little of what I understand (and no doubt Jed will totally correct me!) With High Altitude Ballooning (HAB), there are one of two main aims: 1> Go as high as possible. 2> Travel as far 'away' as possible. A balloon needs to be filled with gases to allow it to 'rise' and then travel. However, it is not like blowing a 'party balloon' up where you 'puff' until it is 'full'. This is because the temperature can vary considerably depending on altitude and this in turn affects the pressure of the gas in the balloon. A balloon can literally collapse if the pressure is too low (and hence fall to the ground), or it can expand until it bursts (and also falls to the ground!) With Jed's latest attempt, he was trying to travel as far 'away' as possible; and this type of balloon is called a 'floater'. It is not initially filled with too much gas as otherwise when it rises it will expand and burst. Likewise it is not filled with too little gas otherwise it won't rise. So he filled it up with a calculated amount of gas. I believe the predicated wind direction and weather in the areas where it will 'float' too may also determine the initial amount of gas? Also the altitude of the 'float' - 8000m in Jed's case. Anyway, during the day, the sun is normally out (or should be!), and this warms the gas inside the balloon, the gas expands, and the balloon rises. If it rises too much, or too quickly, then it will burst! Now at evening & nighttime, the temperature drops, the gas compresses (I think thats the correct term), and the balloon 'falls'. So depending on local weather conditions during the 24hour day, there is a risk of total collapse or of bursting. With a collapse, it the payload is too much then the balloon will fall like a 'lead balloon' So weather, temperature, amount of gas, quality of 'material' the balloon is made out of, and other things no doubt, all play a major part in overall distance travelled. Hopefully Jed will chime in with what he knows happened as to why it came down (assuming it has done so!). It is quite a fascinating 'science'; and all I suggest to Jed is that he now 'floats' a few MMX144 across to Europe with Peter's Camera code  WW For everything Micromite visit micromite.org Direct Email: whitewizzard@micromite.o |
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CaptainBoing Guru Joined: 07/09/2016 Location: United KingdomPosts: 1995 |
I don't know enough about this particular setup but from 25000 feet up, I would have expected to see at least one reading showing the descent. With the tatters of the balloon and line acting as a drogue to slow it somewhat... From my WF33 days (The company I worked for at the time refurbed WF3 for Plessey and I wrote the WinProc and MeteoProc software that piggy-backed the RS232 printer output to produce PILOT and TEMP messages direct from raw radar data - we played with sondes a lot during trials) I have seen balloons go up and down as they pass through cloud layers and ice forms which weighs the balloon, it emerges and the ice melts away and it goes back up. Let a balloon off in Mahe into cumulo and it went round like this three times! EDUPIC16 showed this drop-then-rise (although it might not have been ice) but just vanished from the trace. That it stopped so abruptly and the circuit is open to the atmosphere, I took it that the electronics malfunctioned... very cold and likely damp and the last BVOLTS was 1.4V. It might still be up there! EDIT: just looked again and it says altitude of just 1,700m... forget what i said above. Can't wait for the Post Mortem from Jed. |
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| isochronic Guru Joined: 21/01/2012 Location: AustraliaPosts: 689 |
Isn't dropping lithium cells on people from a few km up, kind of (ed) dangerous at best ? |
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| CaptainBoing Guru Joined: 07/09/2016 Location: United KingdomPosts: 1995 |
dunno if there is some kind of parachute or something. It could be a problem. |
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