LoRa Discovery Kit

[Tesla DeLorean]

Posted on April 05, 2017 at 22:40

LoRa Discovery Kit

STM32L072 and LoRa Discovery Kit featuring Open LoRa module by Murata using STM32L072CZY6TR MCU

http://www.st.com/en/evaluation-tools/b-l072z-lrwan1.html

Features

• Ultra-low-power STM32L0 Series MCUhttp://www.mouser.com/stm32l0, Cortex® -M0+ based with 192Kbytes of Flash memory, 20Kbytes of RAM, 6Kbytes of EEPROM, LCD, crystal-less USB, T-RNG, PCROP
• 157dB maximum link budget
• +20dBm, 100mW constant RF output versus Vsupply
• +14dBm high efficiency PA
• Programmable bit rate up to 300kbps
• High sensitivity: down to -137dBm
• Bullet-proof front end: IIP3 = -12.5dBm
• 89dB blocking immunity
• Low RX current of 10mA, 200nA register retention
• Fully integrated synthesizer with a resolution of 61Hz
• FSK, GFSK, MSK, GMSK, LoRa™ and OOK modulations
• Built-in bit synchronizer for clock recovery
• Sync word recognition
• Preamble detection
• 127dB+ dynamic range RSSI
• Built-in temperature sensor and low battery indicator 1.65V to 3.6V power supply

The AT_Slave example (creates AT modem via ST-LINK VCP) is about 41KB in size

• Attached is original shipping firmware (April 2017) Ping-Pong Demo
• Added LoraDisco_ATSlave_US915.hex a build of the example from the Cube Extensions, USA 915 MHz option selected
• Added LoraDisco_ATSlave_US915_V111.hex a build from the V1.1.1 tree
• Added LoraDisco_ATSlave_US915HYBRID_V111.hex
• a build from the V1.1.1 tree w/US915_HYBRID (17-Aug-2017)
• Added LoraDisco_ATSlave_US915HYBRID_FULL_NOT_TINY_V111.hex.zip a build using Keil native sscanf/printf w/AT+SEND fixed

[Tesla DeLorean]

Posted on August 15, 2017 at 15:57

Going to try and add an attachment...

Apparently I can't do that with blog posts, would need to edit the parent?

[Tesla DeLorean]

Posted on August 17, 2017 at 17:24

Yesterday we dug into the AT_Slave a bit and resolved an issue with sscanf (tiny, or full) breaking on AT+SEND

https://community.st.com/0D50X00009XkXrMSAV

https://community.st.com/0D50X00009XkXrMSAV

Specifically sscanf() expects to write a 32-bit word, you can't stuff that into a 8-bit byte variable, sometimes it might appear to work but is very unsafe and likely to either fail or corrupt other variables.

The Keil build using the full scanf/printf native libraries added about 2KB to the overall build. ie 37KB from available 192KB

I thought I'd checked boxes to allow others to post into the blog. Anyway if you have input you can always 'Share' this entry back to me (top right corner). I'm going to use this as the parking point for my LoRa related experiences.

[Tesla DeLorean]

Posted on August 17, 2017 at 19:20

Stripping MODEM_FSK mode code saves 2KB

[Tesla DeLorean]

Posted on August 28, 2017 at 06:07

https://www.tindie.com/products/TleraCorp/grasshopper-development-board/

Kris Winer has shrunk Arduino type functionality into a minimal footprint using the Murata module.

[Tesla DeLorean]

Posted on September 01, 2017 at 05:09

LRWAN successfully ported to assorted STM32L4 boards using the SX1272 shield

NUCLEO-L476RG

NUCLEO-L496ZG

B-L475E-IOT01A

https://community.st.com/0D50X00009XkgY0SAJ

The Grasshopper boards also arrived today, shipped very quickly/efficiently. The 5 dBi antennas arrived as well.

[Tesla DeLorean]

Posted on September 01, 2017 at 22:25

Ported code to the Grasshopper, had to change TCXO enable to PH1.

PB13 is LED

Schematic looks to be wrong, SWDIO is D8, SWCLK is D9

DFuSe 3.05 doesn't seem to work properly with the STM32L0

USART2 works on PA2/PA3, hooked that up for debug telemetry, equivalent to B-L072Z-LRWAN1 discovery board.

[Tesla DeLorean]

Posted on September 08, 2017 at 23:42

Murata module will also support SigFox with forthcoming firmware

http://www.murata.com/en-us/about/newsroom/news/product/frontend/2017/0718

Update, Andrew caught the release of the software

https://community.st.com/0D70X000006SsniSAC

http://blog.st.com/x-cube-sfox-firmware-sigfox/

http://www.st.com/en/embedded-software/x-cube-sfox.html

[T J]

Posted on September 10, 2017 at 04:16

I haven't used RF comms before, our target markets have facilities usually spread over a km.

I use other Murata parts on my board, do you think their solution is the best to start with ?

I take forever to code my work, I'd like to start with the right solution. Price is not that important, but choosing the wrong platform could be a disaster.

'Currently, Murata’s Type ABZ LoRaWAN™ module, which uses a STMicro STM32-based wireless microcontroller and SX1276 Semtech RFIC, operates in the 806 930MHz frequency band and provides a nominal output power of +14 dBm that can be boosted to +20 dBm for long range or poor signal location applications' I checked the Aust RF allocation chart. too many colors for me... it looks like it is fully allocated.. for mobiles, and ISM ?

in an industrial situation, what range would you expect through concrete walls ?

how do you work through a steel building ? with analogue repeaters or would you run a cable through to a repeating node ??

could you clarify:

which is the best solution to start with for 1km industrial applications ?

I would hope and expect they use spread spectrum RF.

Encryption, is it standard on board or do we have to implement it ourselves ?

[Tesla DeLorean]

Posted on September 10, 2017 at 21:13

Behaviour is highly situational, you'd have to evaluate the technologies in the environment you expect to deploy. I'm working in concrete slab construction industrial/warehouse type buildings, though that's not my target environment. Building penetration at 915 MHz or 433 MHz is going to be significantly better than 2.4 GHz.

I can get 1KM driving within the local business park, with a 5dBi antenna mounted about 5ft above ground in the window of my office. With a better antenna on the truck side, I got around 3KM LoS, this is was without selecting more conservative encoding and spreading settings. I would do better with the antenna mounted 25ft up. I could see one access point serving an entire sub-division of gas/water/electric meters, with the AP on a light or utility pole.

I'm using LoRa in point-to-point and broadcast base-to-remotes rather than embracing LoRaWAN. It is one of the better sub-GHz radios I've worked with.

LoRaWAN uses AES which is pulled in as a software library, you could use that to crypt packets. Basic app uses about 15% of FLASH in this micro. Readily ported to L4 with significantly more horse-power and resources.

The US 900 MHz band is 902-928, centred at 915 MHz

[T J]

Posted on September 11, 2017 at 01:52

Are you suggesting that all antennas should be mounted above the roof ?

Then line of sight transmissions seem easy enough.

do you get any reflection/interaction from a steel roof at an antenna height of 1ft, 10ft above the steel roof ?

/external-link.jspa?url=https%3A%2F%2Fwww.digikey.com%2Fproduct-detail%2Fen%2Fstmicroelectronics%2FB-L072Z-LRWAN1%2F497-17068-ND%2F6616000

I guess I have to order two or three units..

Do you think this solution brings with it a source of interruption ?

did you ever hear of someone deliberately jamming an industrial solution ?

with spread spectrum, is that risk is lowered a little ?

CanBus is limited in range

:(

I need to look beyond CanBus