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Bugs2 Newbie Joined: 18/05/2012 Location: United KingdomPosts: 29
Posted: 09:28am 22 Jan 2015
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There have been a number of successful balloon flights in the EDUPIC series since the original posting about this topic, in early October. This described a short duration latex balloon flight but more recent flights have been longer duration floaters using foil pico balloons. Unfortunately, I have not been able to find any information about these subsequent flights or the associated light weight Micromite based tracker design (maybe I'm just rubbish a Googling).
This is a pity because the Micromite seems an excellent choice for this type of airborne project. Much easer to get started on than the Arduino and demanding much less power than the 'educational' single board computers that some people are flying in the UK. It would be great if the EDUPIC team could find time to share their expertise with the rest of us.
edu001 Regular Member Joined: 14/07/2014 Location: United KingdomPosts: 82
Posted: 10:31pm 22 Jan 2015
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Hi Bugs2
I design and fly the EDUPIC trackers, test flying has been cut short due to winter winds there are far more followers to the East of the UK
The MicroMite addon board should be available around march after more test flights although the floaters you refer to are my own very light pico trackers based on the 170 44 pin chip ans MMBasic
The new version of this has just gone off for manufacturing it runs off a 1S Lipo 3.7v 250ma with Solar charging it is 65mm x 16mm and should weigh around 11g
I have got the power consumption down to 26ma while TXing and 6ma idle
The next goal is to get up into the Tropopause ideally 10km and above the weather thats what usually brings them down
Version 3 should have APRS capability I am working on pointinpoly for geofencing now
There will be some hi altitude flights this year using the MicroMite and a larger Raspberry Pi based payload, the latter will carry the cameras/sensors and possibly TX live images
The plan is to ascend to around 37km then use the MicroMite to cut the Pi free leaving the MicroMite to ascend hopefully to over 40km
Are you planning on building a tracker ?
Bugs2 Newbie Joined: 18/05/2012 Location: United KingdomPosts: 29
Posted: 06:46am 23 Jan 2015
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Hello and thanks for the update. I quite understand the weather issues because it was -5 C here to the north of London last night and didn't much warmer in the today.
Your Micromite based projects are certainly very impressive. Regarding your aim of achieving longer flights, by getting above the weather, its interesting that Leo Bodner's multiple circumnavigation pico flight were undertaken at about 12km.
Are you aware of the LoRa balloon tests conducted recently by Stuart Robinson (of $50 SAT fame) in the UK? He has published detailed results and predicts that a LOS range of over 600km should be possible using only 10mW at 433 MHz.
Good to see all his projects use PICAXE microcontrollers and that you are both helping to offer credible alternatives to the Arduino, which had become dominate in the UKHAS community.
I'm not so much planning a tracker as developing an avionics platform for science experiments. I have past experience based on large zero pressure balloons (launched in the US and Europe) but now think useful research could be undertaken by small latex and foil balloons.
Thanks again and look forward to learning more about your work.
srnet Senior Member Joined: 08/08/2014 Location: United KingdomPosts: 164
Posted: 11:27am 25 Jan 2015
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Are you going to open source the MM code ?
I have in mind building a portable LoRa receiver that had its own GPS, receives the LoRa telemetry from a HAB and does the distance and direction calculation for you, displaying the results on an LCD.
I did manage this feature with a PICAXE but it was limited to around 60km.
An MM would appear to be good platform for such a device, and I have some Mikrobasic code for the distance and direction calculation, so it should be similar to MMbasic.
Stuart Robinson
GW7HPW$50SAT is Silent but probably still working. For information on LoRa visit http://www.loratracker.uk/
edu001 Regular Member Joined: 14/07/2014 Location: United KingdomPosts: 82
Posted: 12:25am 26 Jan 2015
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Hi srnet
I have been reading your posts on the LoRa module very interesting, I am making good progress with the RFM98W on the MicroMite but I don't know if I will end up using it
So far I have very reliable RTTY code and DominoEX16 is 95% complete, I can decode all but a couple of characters, it's timing issues, I would like to add more MFSK modes and stick with the MTX2 transmitter, with intermittent transmissions of 2 mins I can get 96 hrs+ on an AA
There is new board that is Lipo + PV, it should arrive in the next week or so from hackvana then APRS :)
I will be releasing the code and a board design for the MicroMite when I am happy that its as efficient as it can be
srnet Senior Member Joined: 08/08/2014 Location: United KingdomPosts: 164
Posted: 09:57am 26 Jan 2015
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The LoRa\RFM98 is not so difficult to drive, a fair bit easier than the RFM22B for instance. I think for HAB use it will find a niche, perhaps for local 30km+ high launches where you can use it to track without needing the Spacenear stuff, and of course for high data rate downlinks. It could also serve as a very power effiient way of tracking floaters, but it's likley to be a while before there are listenting stations outside of the UK.
$50SAT is Silent but probably still working. For information on LoRa visit http://www.loratracker.uk/
srnet Senior Member Joined: 08/08/2014 Location: United KingdomPosts: 164
Posted: 02:57am 30 Jan 2015
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edu001;
How are you monitoring battery voltage on your tracker ?
I note that the Micromite does not have an internal Vref, so do you just rely on a stable VDD supply ?$50SAT is Silent but probably still working. For information on LoRa visit http://www.loratracker.uk/
matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 10197
Posted: 04:48am 30 Jan 2015
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"print pin(0)" will give you the reference voltage - nominally 1.2V details in the manual page 29
srnet Senior Member Joined: 08/08/2014 Location: United KingdomPosts: 164
Posted: 06:53am 30 Jan 2015
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OK thanks, so as long as you read the 1.2V ref when the VDD is known to be at the regulator voltage, you have a calibration value. $50SAT is Silent but probably still working. For information on LoRa visit http://www.loratracker.uk/
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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