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Forum Index : Microcontroller and PC projects : MicroMite II LoRa Library Programs
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| srnet Senior Member  Joined: 08/08/2014 Location: United KingdomPosts: 164 |
Semtech released the SX127X series of LoRa RF transceiver ICs late in 2013 and these are now available in a number of modules, two of which are of interest to the hobbyist, the Dorji DRF1278F and the Hope RFM98, both are a similar size and cost to the Hope RFM22B. These are devices designed to operate principally in the ISM bands, 434MHz in the UK and Europe. LoRa (for Long Range) is a type of chirp spread spectrum modulation which is completely different to the modulation used on FSK transceivers of which the RFM22B is a popular example. The benefit of LoRa is that it offers a substantial link margin improvement of around 20dB over previous FSK devices, this equates to a distance improvement of around 10 times. At very low data rates, 100bps or less, the LoRa device can offer a link margin improvement of a further 10dBm. A report on the testing and capability of the LoRa devices called “Semtech LoRa Transceivers – a KISS approach to Long Range Data Telemetry.PDF” will be found on the HABAXE2 Dropbox here; https://www.dropbox.com/sh/5ceassf1mp6mg7p/AADnVMI61RLUVln1X 8Tg83oFa?dl=0 I had already successfully developed, tested and flown a High Altitude Balloon (HAB) tracker based on the RFM98 LoRa device and a PICAXE 28X2. A portable PICAXE LoRa receiver was also built, which works well, but I wanted to include some features into the receiver that would be difficult to implement using PICAXE Basic. The PICAXE basic routines were therefore translated into MMBasic and are presented as a set of common routines that can be used to set-up the LoRa devices and send and receive packets in any of the modes the LoRa device is capable of. The programs are in the dropbox 'MicroMite II' folder, together with notes on how to use them. I found the PICAXE programs translated well to MMBasic, and the result is a set of programs that are a lot easier to understand. What would help with program development is a good syntax editor attached to the MMedit program, I note it has an option for this, as yet has anyone produced a syntax checker ? $50SAT is Silent but probably still working. For information on LoRa visit http://www.loratracker.uk/ |
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TassyJim Guru  Joined: 07/08/2011 Location: AustraliaPosts: 5918 |
There is a space in the link above (caused by the forum software) This link should work: link There is lots of interesting material there. I have considered a syntax checker for MMEdit but it's the sort of thing that has to be done right or it would cause more problems than it solves. Jim VK7JH MMedit  MMBasic Help |
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| edu001 Regular Member  Joined: 14/07/2014 Location: United KingdomPosts: 82 |
Nice work! are you going to fly a MicroMite/LORA payload? I will be interested to see how it goes |
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| srnet Senior Member Joined: 08/08/2014 Location: United KingdomPosts: 164 |
No Plans at the moment. The PICAXE PICO one works well enough, not sure it could be improved really. A bigger tracker, doing more stuff, would probably benefit from a more capable Micro. It was doing more at the receiving end of the telemetry, without needing to be tied to a PC, that attracted me to the MMII. $50SAT is Silent but probably still working. For information on LoRa visit http://www.loratracker.uk/ |
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| srnet Senior Member Joined: 08/08/2014 Location: United KingdomPosts: 164 |
There does not seem to be a lot of interest (as yet) in the LoRa devices for HAB tracking, which surprises me, the telemetry is easy to receive and has close to the range of FSK RTTY, plus the devices do give you the option of FSK RTTY as well. There is a RFM98 shield for a Pi coming soon from HAB Supplies, but they will need to sell quite a few to justify the expense of all the CE stuff. $50SAT is Silent but probably still working. For information on LoRa visit http://www.loratracker.uk/ |
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| Bugs2 Newbie  Joined: 18/05/2012 Location: United KingdomPosts: 29 |
If they use a Pi on the airborne side of the link they will need a pretty hefty battery that rather rules out small foil balloon flights. |
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