## Northern Zephyr… Implementing a new Board on Zephyr Project

We implemented a low powered battery operated product using LoRa. We implemented the proof of concept using the Ronoth LoDev board, then placed the main chip, the AcSIP S76S SiP, onto our own little board. Neat little chip! Oops, module. This neat little chip (there I go again) contains an STMicro STM32L073RZ ARM MCU, a Semtech SX1276 LoRa transceiver, and a +20 dBm power amplifier.

While I was working at Savoir-faire Linux, Jérôme Oufella suggested that I look into the Zephyr Project RTOS, which is a project of the Linux Foundation. Sure enough, both the STM32L073RZ MCU and the SX1276 transceiver are supported.

It was a pretty simple task, so I created a board support entry for the Ronoth LoDev in the Zephyr Project. Well, it wasn’t all that simple at first – the Zephyr maintainers had concerns about the way that I organized the files (rightfully so), and we took a long time reorganizing and refactoring the code. But in the end, I created SiP support for the AcSIP S76S chip (oops, module) and for the Ronoth LoDev board, and a few days ago, it was merged back into the master, yay! Here\’s the board documentation that I created… hmm there\’s a typo in there, grumble, will have to fix… some day!

## Breathing New Life into Old SBCs with Real-Time Linux

While working at Savoir-faire Linux (SFL) in Montreal, I was commissioned to perform some Linux experimentation on an old SBC, using Buildroot, the PREEMPT-RT kernel build option, and FTrace. The first two articles have been posted on SFL’s web site – part 1 and part 2.

Although the work dried up and they let me go, I still believe in the folks at SFL and their work.

A new article was recently posted on Hackaday which discusses Real-Time OS basics, I recommend it for an interesting, short, read.

## Long Text Messages

SMS text messages are historically limited to 160 characters (70 characters if in unicode). Years ago, devices would refuse to send a longer message, forcing users to break the message up themselves. These days, however, most devices will allow a user to create a much longer message.

So, what happens when you send a longer message?

There are two ways to handle SMS messages of excess length:
1. Split the text into multiple shorter messages, which might be reassembled into one message by the receiver, or might be presented as multiple messages. Each message is shortened by a few characters, to put in a reconstruction header that the receiver can use to put it together.
2. Change the text to an MMS message, which actually uses the data plan to communicate.

## What is this MMS of Which You Speak?

MMS is an alternative texting data format that can also do images, sound files, etc. On most devices, if you try to send a text with a picture or other media file, the entire message is automatically upgraded to MMS. As mentioned, this uses the data plan to send the content, but uses the SMS channel to send meta-data that advises the receiving device to load the actual message using its data plan.

## “Legacy” SMS Support on VoIP.ms

Up until August 2020, VoIP.ms did not support MMS. Neither did the two most common means of sending and receiving text messages on their platform. They do provide an API whereupon you can write your own interface (as Michael did for item 1 below).
1. The android application VoIP.ms SMS is an open source project developed by Michael Kourlas, an independent programmer. It only supports SMS, never has done MMS. Also, this application relies on his servers to transfer data – for which I am thankful, because I appreciate the service!
2. The “legacy” web application, has no MMS.

In both “legacy” programs,
1. If you try to send a long message, it splits it up automatically, according to the standard.
2. You can’t send any media.
3. If someone sends you a long text message, it’s a crap shoot – if it is split up by the sender, the pieces come through. If it isn’t split up, the message is just silently lost.
4. If someone sends you media, the message is just silently lost.

## “New” MMS Support on VoIP.ms

A few months ago (around end of August), VoIP.ms started supporting MMS using a new web interface from the main page -> DID Numbers -> SMS/MMS Message Centre, or directly at the SMS/MMS portal. Here, you can do full SMS and MMS send and receive.

Now, can you use VoIP.ms as a “complete” alternative to your cell phone texting? Well… yes, and no.

### Upgrade for the Android Application Some Day?

The old “legacy” app and web site still work, but they have the same limitations that they always had. This is unfortunate, especially for the Android app – it sure would be nice to have full MMS support on mobile devices. I’ve contacted Michael and asked if he planned to support it eventually, and he said “yes”, but had no further details. I thought I might assist, but when I looked at the code… well, it’s Android code, and it’s pretty opaque.

## Not All Providers Can Send to VoIP.ms Text System?

Yes, if it works, then you are away to the races. I use it all the time to keep contact with folks in the US and elsewhere.

The interesting thing is that some texting systems will not send to VoIP.ms text system, not sure why. There is some kind of “provider matrix” used by each telco for delivery of their texts to another telco, and for whatever reason, VoIP.ms isn’t on some lists. For instance, my bank in the USA tries and tries to send SMS texts to my VoIP.ms number to confirm my login, but it never works. The telco automation provider Twilio sometimes has trouble too.

It all seems kind of hit-and-miss. Maybe harassing the VoIP.ms guys would get them to chase it down and get onto those “choice matrix” lists, but I have not tried.

### Text Message Provider Matrix

This text message “provider matrix” thing has been around for a long time. Long time ago I found that every telco has an incoming E-mail to text message portal – and found out that you can just carpet bomb all of them with the telephone_number@each_telco. Those telcos who don’t have the specified number will silently ignore. By extension, connection between telcos is probably done the same way. If VoIP.ms were not on the list, then they would not get the message, and would not receive the text.

## Other Means of Getting Your VoIP.ms Text Messages

You can also have text messages forwarded to a “real” cell phone, but you do have to remember if you reply that it comes from that “real” cell phone – so your correspondents will send to one number, get back from another. Worse if that number is out of country – you reply, it comes from your “real” cell phone, and you get charged for it.

You can also have incoming text messages bundled into an E-mail, but not sure how you would reply to that.

## The Not-So-Secret Secret to Refilling Foaming Hand Soap

It was expensive, but I purchased a foaming soap dispenser for beside the bathroom & kitchen sinks.  I prefer foaming soap – it just feels better on your hands, it goes further than liquid soap (and has to be filled less frequently), and I believe it actually works better to clean your hands, than does liquid soap.

The challenge came when the dispenser was empty.  There (apparently) is no refill for foaming soap.  Sigh.  All you can get is liquid soap, like below.

At first, I just filled the foaming soap dispenser up with liquid soap.  That didn’t work at all.

Then, I experimented with dilution of the soap with water.   It works!

Fill the foaming soap dispenser to about 20% level with liquid soap.
Fill to about 80% level with water.
Be sure to leave significant space on top - probably more than you would be inclined to do with just liquid soap!
Slowly rotate the dispenser to gently mix the soap and water.
Dispense!

## America’s best buy for a nickel…

I don’t recall when I first heard that phrase, but it contains such insight.

America’s best buy for a nickel is a telephone call to the right man – Ilka Chase

You cannot know everything.  Don’t even try!  Instead, take the time to cultivate personal and professional relationships with those who expand your horizons, have knowledge complementary (or orthogonal) to your own, and whom you can contact when you need advice, suggestions, or knowledge.

That’s not to say that you shouldn’t strive to be the best, most well rounded expert at what you do!  Rather, there are always going to be areas of knowledge at, or just beyond, the limit of your understanding.   When that happens, don’t guess at it unless you have to – instead, if at all possible, talk to someone who knows that area better than you do.

The brush paints in both directions.  If you are conscientious and diligent in your own area of expertise, then you, in turn, will the a person to whom others turn to, when they need some sage advice in your area.

Don’t use this as an excuse to vacillate: when you have to make a decision, then by all means, decide.  When time frame or circumstances determine that you must make your best stab at a fix, go for it!  But, when you have the time and opportunity to reflect on something just out of your technical grasp, think about who you can contact to give you the advantage you need.  And, don’t hesitate to give similar assistance to others who call upon you.

## VoIP.ms SMS and Call Forwarding

So, here is how to set up VoIP.ms for SMS texting and call forwarding.

# Important Term “DID”

The first thing to know is a specific term.  DID, or “direct inward dial”, is your telephone number that can be called.  In other contexts, it can mean the phone that will be connected to, when someone dials that number.  In our context, it will just be the number.

Why the distinction?  Outbound calls use a different system.  Simple as that.  Leave that for another time.

Bear in mind that, although the base cost for each DID is ridiculously low, nothing is free.  SMS texts cost something like ¾ cent each, inbound and outbound calls cost by the minute (something around 1 cent per minute).  I find this acceptable, because there’s no way that I could ever even come close to the cost of my old phone bill!

# Accounting

OK, first thing is to create your account and fund it.  All amounts are in USD.  I would suggest using PayPal to fund it, and I’d suggest putting in US20 or US30 to start.  You can set an “alarm” on your account to send an E-mail when your balance falls below a certain amount.

Once you’ve got your account and it is funded, then for the task at hand, here are the main management menu items you will use.

# Set Up Call Forwarding Target

First, set up a call forwarding target.  Select “Call Forwarding” and create an entry pointing to where you want calls to be potentially redirected to.  You can create more than one – you can select which one is the actual target, for each DID.

Here’s a sample entry screen.  You don’t have to touch anything else except to put the 10 digit phone number of the target to forward calls to.

# Ordering Arbitrary DID(s)

If you don’t have any DID(s) yet, you will have to go to “Order DID” first, and create them.  The word “order” is a bit of a misnomer, because it’s all automatic and practically immediate.  You can create as many as you want, and it’s quick.  You can pick a telephone number in pretty well any area code in North America, and some numbers overseas.  Be conscious of their cost, they don’t all cost the same in monthly cost or in inbound & outbound per-minute charges.

You can also “port” your existing number from a cell phone or landline phone carrier to VoIP.ms.  It’s a bit of a process – not that hard, you just have to read the procedure and go through the steps.  The telcos are anal about making sure you follow the steps – they are trying to prevent port-out fraud, which has happened in the past, with disastrous consequences – think “SIM hijacking”, not nice.

Anyway, it is standard practice these days to set a port PIN on any mobile DID.  This is wise to do.  Be sure to keep it private.  If set, then without this PIN, port requests are ignored.  Of course, keep track of that port PIN, or else you won’t be able to perform a port either 😊   Keep these things in your password manager (use LastPass – don’t pass “go”, don’t do anything else – just do it).

When you port your cell phone number, be sure to indicate that it’s a mobile/cell phone.

# Managing the DID Settings

Anyway, once you have any kind of DID in your account , go to “Manage DID(s)”:

On the left, under “Actions”, you will see three coloured icons – an orange pencil & paper (edit this DID settings), a blue paper with lines on it (read-only view this DID settings), and optionally a green cell phone, which indicates that this DID supports SMS & MMS.

Click the orange pencil & paper icon, which should bring you to this screen:

Select “call forwarding”, and if necessary, drop the selection box and choose where to route the call.

Scroll down and choose the DID point of presence:

This simply is the Internet server location that you will connect to, when you come around to using a VoIP phone.  I would select one close to your primary use location.  You can change it later, but for your VoIP phone to work (inbound and outbound), your VoIP phone must point to the same server name.

Continue to scroll and you will see the SMS settings.  Above that are a few key settings related to the cost of calls, review each one.

For SMS, you have to “enable SMS/MMS” and, if you want to SMS/MMS forward, to select this option and put the 10 digit target telephone number in here as well.

The “SMS/MMS URL Callback” option is for use with the VoIP.ms Android SMS application, see below.  You can leave it unchecked, but the value should be “https://us-central1-voip-ms-sms-9ee2b.cloudfunctions.net/notify?did={TO}“, per below.

Save the changes, and it should work!

# Installation of Android App to Support Near-Native Texting

There are a few limitations, but it works very well for me.  It’s how I keep in touch with my friends in Phoenix (and formerly of Phoenix 😊).  I ported my US cell phone number to VoIP.ms and use this app to text with them.

Here is the Android application:

Now, the difficult part – setting it up.  The app is open source, and its help page looks like this:

You have to enter that string into the DID’s “callback” entry (see above),  then enable the API connection back on VoIP.ms, see below

# Enabling the API Connection

From the VoIP.ms main page, select “Main Menu”, then “SOAP and REST/JSON API”:

Put in an API password (this will be what you give to the Android app, above), enable the API, and ensure that the “Enable IP Address” is set to 0.0.0.0.  You can restrict the IP address here, if it is well defined and won’t change.

# Thomas Sissons Yuill

In 1875, Thomas Sissons Yuill was born second son to pioneers, and some of Manitoba’s first Homesteaders, Alexander David Yuill (A.D.) and Willena (Sissons) Yuill.

In 1911, Thomas was a single popular young man and was farming 34-12-7, just north of Portage la Prairie. Along with brother David, the “Yuill Brothers” also owned and worked farmland at Lakeland, owned and worked a wood lot at Riding Mountain, as well as having built themselves a cabin on Lake Manitoba.

The wood lot kept the “hired hands” busy during the winter months.  Ducks, geese and elk were hunted from the cabin. They could also harvest fish and the ice for the “ice house” from the lake. They did mixed farming – they raised animals as well as doing grain farming. Horses, a small herd of cattle, pigs, and chickens filled the barn. The milk was sold to the creamery, and for a short time, Thomas continued using mules to haul freight between Winnipeg and Portage, as his father had done before him.

In fall these busy farmers would move the thrashing machine to Lakeland by way of the railroad.… which was a daunting, yet necessary, feat!

On December 2, 1911, Thomas and David had completed the day’s work when there was a terrible accident.  An account of the incident is noted in the newspaper clipping which follows.

Thomas is buried in the cemetery on the corner of A.D. Yuill’s land (34-12-7), which his grandfather passed on to the Trustees of the Congregation of the Presbyterian Church in Prospect of Manitoba November 5, 1897.

Pioneer farmers faced many challenges. It was a great feat for a child to reach adulthood. It was a terrible loss when they died in early adulthood.

# Clarence Alexander (C.A.) Yuill

Clarence Alexander Yuill was born in 1905 to David Williamson Yuill and Annie (Grobb) Yuill, on his grandfather’s homestead north of Portage la Prairie.

Married in 1928 to Verna Mae Gallaway, in the early days they practised mixed farming while they raised their young family. The grain paid the bills, while the animals and garden produce fed the family. You did not eat what you did not grow!

In later years rapeseed, flax, malt barley and sugar beets were added to the traditional grains.

C.A. was a sociable person and kept a busy schedule. He played saxophone and piano. He enjoyed tinkering with radios and machinery, which resulted in the establishment of electricity (his own version of the “Delco-Light”) and running water on the farmstead, far ahead of his peers.

Clarence’s many interests included being a member of the Portage District Plowing Association, member of the Portage Flying Club, trustee of West Prospect School from 1942-1954, then President of (new) Rural School Trustee Association. He worked for four years with the Manitoba Deputy for the Department of Education and the Manitoba Minister of Education to establish a High School for Rural Manitoba students, who until then, could only take High School by correspondence. He was therefore one of the founding members of the Rural Secondary School Board, and was instrumental in obtaining Portage la Prairie St. Mary Parish Hall as the first rural High School room in Manitoba.

Clarence was Councillor (Ward Three) for the RM of Portage la Prairie from 1964-1977, in total spending thirty-five years as a School Trustee and Rural Councillor.

In 1979, C.A. was presented with an engraved Centennial Commemorative Medal by the Manitoba Historical Society.  Recipients were selected for “recognition of personal contribution to the way of life in Manitoba”.

C.A. was a bit of a joker, so Verna had to be on guard… one New Year’s Eve they were returning from a neighbour’s party when Clarence drove past the end of the farm lane. He was driving a new car purchased that afternoon.

“You’ve missed our turn!” stated Verna.

“Here, you drive!” Clarence exclaimed, as he pulled off the steering wheel and handed it to her. It had disengaged from the steering column!!

# Summary of Transceivers

## Round 1

Reyax RYLR896 module (have 3 of them) – contains RYLR890 RF module (which apparently contains Semtech SX1276 RF chip) + STMicro STM32L151C8T6A MCU – has TTL async interface, so used USB to TTL serial to talk to it.  Reliable communications but weird, uses “AT” command set.  I see this as being a replacement for the EOL’d Linx Technologies FHSS radios on the RMM – but the command protocol is different, so I’d have to rework the Microchip PIC18LF4321 MCU code.  To replace the CM, I’d use this module and say the Silicon Labs EFM8UB2 Universal Bee to translate the weird commands to emulate the old Linx FHSS radio.  The EFM8UB2 has built-in USB interface, SPI, 8051 core, and lots more – I used it in the DC Module at ERLPhase, and I like the chip.  I have the dev kit for it.

Ronoth LoStick (have 2 of them) – contains Microchip RN2903 RF chip + USB interface.  I got them to talk to themselves, that was easy.  I’d love to use this to replace the Collector module, but it’s not clear how to get it to talk to the Reyax RYLR896, haven’t been able to make it work.  Its settings are very different than the Reyax RYLR896, so I haven’t been able to make them intercommunicate.  The internal design and internal software do not appear to be open source.

Waveshare SX1262 LoRa HAT for Raspberry Pi (have 1 of them) – contains EByte E22-900T22S RF module (which apparently contains Semtech SX1262 RF chip + not sure which MCU) also has USB interface that I used to talk to my computer directly to the EByte module.  This looks cool, has its own Wiki page describing it, and example code.  I modified a Python program to talk to it, but couldn’t get it to respond.  Tried all the baud rates, put a bunch of debug in there, just not responding… although I seem to see blinky lights saying that the RX & TX are working…

HopeRF RFM95W little LoRa module (have 2) – pretty small – almost small enough to use on a puck – castellated “postage stamp” SMT mount.  Apparently has an Semtech SX1276 RF chip inside – which should make it compatible with the Reyax RYLR896… it needs sync serial (SPI) and I have no easy way to talk to it.

Microchip (formerly Atmel) SAMR34 (have 1 DM320111 SAM034R Xplained PRO dev kit).  This is yet another architecture, contains a 32-bit ARM Cortex M0+ MCU and LoRa Transceiver.  I have not tried it yet.

## Round 2

Seeed Systems Dragino LoRa/GPS HAT for Raspberry Pi has a HopeRF RFM95 (ordered 2 on 2020-04-11 – arrives in about 2 wks) (not “W” – not for North America) on it, but I plan to change it to my HopeRF RFM95W so can control directly from my Raspberry Pi through its SPI port.  This appears to be an open design with its own Wiki page, and there’s instructions on how to set it up to do LoRa on the Raspberry Pi, and Github code to do LoRa on the Raspberry Pi.  This LoRa/GPS HAT for Raspberry Pi also appears to be available from Antratrek in the UK.

Adafruit has a RFM95W LoRa Transceiver breakout board that would make it easy to play with the Hope RFM95W, but they are out of stock, Antratrek in the UK appears to have some.  There are similar products from Tindie and another one from Tindie.  Maybe I’ve got enough RFM95W options at present.

Ronoth  LoDev  ( Ronoth are the folks who made the LoStik).  It’s a bit newer than LoStik, appears to be a different focus.  It uses the AcSip S76S system-on-a-chip (which they call SiP – System in Package).   The S76S contains a Semtech SX1276 RF chip and a STMicro STM32L073x MCU.  It’s sold out at Ronoth, but CrowdSupply says they have some, so I ordered 2 pcs from CrowdSupply on 2020-04-12.

## Round 3

I retrieved my personal Raspberry Pi 3 B+ from the office – where I had it placed to facilitate my staff being able to navigate to an important source scanning site from their homes – no longer required because the local IT folks spun up an Ubuntu virtual machine to use instead.  I put the Waveshare SX1262 LoRa HAT for Raspberry Pi onto my Raspberry Pi, and gave it a try.  Well, had to remove the Raspberry Pi from its nice little plastic Adafruit box, because the LoRa HAT interfered with the internal ribs.

Anyway, after some fiddling, I was able to get the first stage of talking to the LoRa HAT to work… but after ser.inWaiting() said there were characters waiting at the port, the subsequent ser.read() call caused an unceremonious abort.  No message, no nothing.  I wasn’t happy with this, but after playing around for a bit, I abandoned my efforts.  Oh, well.

So, overall with the Waveshare SX1262 LoRa HAT for Raspberry Pi , it seems that the mode pins are important and have to be twiddled in order for the board to work.  That’s probably why I couldn’t make it work on USB from my LINUX computer.  That’s a problem for another time, perhaps.

## Round 4

Back to the Waveshare SX1262 LoRa HAT for Raspberry Pi .  With manually twiddling the pins, I can talk to the RF module in configuration mode, and got it to respond.  There seems to be a “temporary” configuration and a non-volatile configuration.  Even when I’ve written the parameters I want to non-volatile configuration, then unplug, switch mode bits to talk through the radio, and have the Reyax RYLR896 module chattering away beside it, I get nothing.

What I have is one Reyax RYLR896 module set as Network ID 6, Node ID 10, alternating transmissions to Node IDs 20 and 30 (yes, in decimal – I checked).  Then I have a second Reyax RYLR896 module set as Network ID 6, Node ID 20, receiving the alternate transmissions.  So, I set the Waveshare SX1262 LoRa HAT for Raspberry Pi set to what I think is the same frequency, and as Network ID 6, Node ID 30 (0x1E)… and receive nothing.

I’m not absolutely sure they are set to the same transmission parameters.  I see no way on the Waveshare LoRa HAT to set Bandwidth, Spreading Factor, Preamble, or Coding Rate.  Hmm, and the frequency is 850.125 MHz + ((0 to 80) x 1 MHz) – so I set it to 915.125 MHz.  Does the 0.125 MHz offset matter?  Argh!

The EByte E22-900T22S RF module , which is the RF module on the Waveshare LoRa HAT, has documentation which is rather sparse.  It documents only 9 registers to set (although it does show all the bit settings) from locations 0x00 through 0x08, and then another 7 bytes of identification at 0x80.  I cycled through the entire space from location 0x00 through then end of the identification.  I found several more non-zero values up to location 0x17.  Perhaps they hold the key to interoperation with the Reyax RYLR896… then again, maybe not.

Read out registers:
0x0000: 00 1E 06 60 00 41 00 00  00 00 00 00 22 14 16 0B
0x0010: 00 00 08 08 C2 03 01 63  00 00 00 00 00 00 00 00

0x0080: 00 22 14 16 0B 00 00

I went to the datasheet for the Semtech SX1262 radio chip that’s inside the Ebyte E22-900T22S RF module, just to see if maybe if I could infer more from that – if the existing E22-900T22S commands were reflected in the SX1262, there might be details of other commands.  Apparently not, the structure is completely different.  It makes sense, because the SX1262 communicates solely by SPI interface… and the E22-900T22S talks by async serial – so there must be a chip inside there to do the interpretation, and perhaps other things in the protocol.  I do seem to recall seeing something about this MCU, but from the Ebyte E22-900T22S documentation, it does not appear to be exposed to the outside world, so working on that could be a severely uphill battle.

Oh well, I’m honing my Python serial skills, and almost ready for the other modules to arrive – Seeed Systems Dragino LoRa/GPS HAT for Raspberry Pi should be here this week – the package is currently in Cincinnati, OH, at the DHL warehouse.  Apparently, the two pieces should arrive on Tuesday.  I hope so – I had to pay duties & fees on it 🙁    I will still have to switch the radio module on both pieces – although I might test it at the (wrong for North America) frequency of 868 MHz first.

The Ronoth  LoDev has not shipped from CrowdSupply after a week; I suppose that means that it’s not in stock in their warehouse…  or maybe this COVID-19 trouble has got them waylaid.  That’s unfortunate, because I see the S76S module on the LoDev as the ultimate long-term solution – it has the MCU on-board, I can program it, it has a good example, and can support USB – well heck, maybe the LoDev itself would be the CM replacement.  Anyway, it could work well in both the RMM and the remote in-the-ice measurement “puck”.

# Next Steps

## The RFM95W Approach

The Seeed Systems Dragino LoRa/GPS HAT for Raspberry Pi has the European frequency LoRa chip on it but the same footprint as the North American frequency HopeRF RFM95W module, which I have here.  I can switch the modules so that the unit is on North American frequencies, then put this onto the Raspberry Pi, load up the Github code to do LoRa and try to talk to the Reyax RYLR896.   I’m not sure if this will lead to a viable solution – it would be more economical to buy Reyax RYLR896 modules and add the EFM8UB2 Universal Bee to translate between the silly “AT” commands and the old Linx Technologies FHSS protocols.  I’d like to replace the STMicro STM32L151 MCU on the RYLR896 board, but the code doesn’t seem complete – looks like it might be a bear to get up and running… might be worth the trouble, if I could maybe just reprogram the STM32L151 MCU to do the whole job and emulate the Linx Technologies FHSS protocols directly (instead of “AT” commands).

## The S76S Approach

Assuming that I can get the LoDev from Ronoth to talk, and can program the MCU inside of it, then I could develop a version that would emulate the old Linx Technologies FHSS protocols inside the MCU.  That MCU has USB capability, so it could be a single-chip solution for a revised Collector Module (CM) and still talk to the legacy MS-Windows software using this emulation.  On the other hand, it also has async serial capability, so it could be a single-chip solution to replace the Linx Technologies FHSS modules inside the Remote Measurement Module (RMM) without changing the programming of the Microchip MCU inside it, again using this emulation.  Thirdly, the S76S chip has I2C and SPI capability, and it’s tiny, so with a temperature sensor, it could become the basis of a new “puck” to be buried in the ice as well.

## Common Ground between the Approaches

Since both the Reyax RYLR896 and S76S modules have the Semtech SX1276 RF chip inside, it’s also possible that they could both be interoperable with each other… although, based on my recent experience, I won’t hold my breath on that.  Having options is always a good thing!

## Beating Up on Some Existing Ones a Bit More

I might work on the Waveshare SX1262 LoRa HAT for Raspberry Pi a bit more.  I seem to recall that I got it to answer to my settings etc., but upon further review of the Python code, maybe I didn’t 🙁  I should review again.

A second review of the Ronoth LoStik shows that its settings aren’t so much different than the RYLR896.  Maybe I need to revisit this one.

I’ve also got 2 different ST-LINK/V2 debug adapters – one “official” STMicro one, and one cheap knock-off (because it arrived quicker and was really inexpensive), so if I could figure out how to set up the whole STM32L151 development environment to reprogram the Reyax RYLR896, I could do that.

## LoRa in Action?

The LoRa modules came in.  1 x Reyax RYLR896 Module, 1 x Ronoth LoStik USB LoRa stick.  I realized that I didn’t have any TTL level serial devices near at hand to talk to the RYRL896, so then I ordered 2 x Covvy CP2102 USB to 3.3V/5V TTL Serial devices.

There are some Python code examples available for the LoStik on github, so I snagged them and gave them a run.  The easiest one is to toggle the on-board LEDs, and that worked fine, but the transmit/receive didn’t do much of course, because I don’t yet have anything set up to transmit/receive with!  Sigh.

I did set up a Raspberry Pi 3+ to talk to the LoStik though – with WiFi access, VNC desktop, and full Python implementation.

Once the CP2102s arrived, I wired one up with the RYLR896, plugged it in, found out that it enumerated as /dev/ttyUSB0 on my system, and fired up minicom with the default settings of 115200 bps, 8/N/1.  Sure enough, I could get a response from the RYLR896, but it constantly said “+ERR=1” with every character.  I’m pretty sure that it timed out between characters.  Try as I might, I couldn’t get minicom to batch up the characters and only send when I hit <RETURN>.  Well, that and it was confusing on how to get <CR><LF> at the end of the line…  let’s see…  stty cooked </dev/ttyUSB0… what else???  Argh.

So I installed and tried puTTY.  It’s in the repos, apparently!  Wow.  Same thing, argh.

Then I tripped over this Youtube video showing use of the RYLR896, and it showed a terminal emulator called CoolTerm, available for LINUX, Mac and MS-Windows.  Sure enough, it’s the real deal, with a GUI, and the right options to allow “Line Mode”, Local Echo, and CR+LF on <ENTER>.  It worked!

The RYLR896 “AT” commands are case sensitive.

Now, to see if I can get the LoStik to talk to the RYLR896…

I’ve ordered a second LoStik and a SX12621 LoRa HAT for the Raspberry Pi.

## Modern RF Communications Modules

Filipe and I have been looking into expanding and extending the Eye on the Ice(tm) system for Hans Wuthrich of Ice Consultants International.  The original system was developed around 2008/2009 by my team at Norscan Instruments Ltd., back when we were diversifying our product offering.  I was Product Development Manager with a fantastic group of very talented people working with me.   They did a great job of the design of the Remote Measurement Module (RMM), the Collector Module (CM), and the MS-Windows software that went with it.  It’s a great system!

Alas, RF modules eventually go obsolete, and the ones used in the Eye on the Ice system will likely soon be unavailable.  They might be around for a few years, who knows, but the writing is on the wall – technology changes, RF emissions regulations tighten, and products change.

Last fall, and into the new year, Filipe and I did a proof-of-concept for an in-ice Eye on the Ice sensor which would use Silicon Labs Zen Gecko EFR32ZG14, the Zen Gecko.  Although the system did work, we found that the low-level control of a mostly-asleep sensor was going to be a huge job.  The examples given, and the information provided, just weren’t enough to get us over the challenge.  In addition, the Z-Wave devices appear to “retry themselves to death” if the central station goes away – not a good thing for a low-cost, sealed temperature sensor device.

One thing that looks like an interesting alternative is the LoRa system – long range, low data rate, adaptable for different jurisdictions.  Probably an excellent alternative for transmission of data like Eye on the Ice.

There are modules available to test – look at the Reyax RYLR896 LoRa Module at Amazon, a LoRa Hat for Raspbery Pi at Amazon, a LoRa USB stick at Amazon.  There also seems to be a LoRa book, but it has bad reviews.

The Reyax web site has a few interesting LoRa modules.  Their modules use “AT commands” to set centre frequency, spectral parameters, and data rate.  With that in mind, these modules could almost be a drop-in replacement for the present Linx FHSS modules that Eye on the Ice uses!

The RYLR896 LoRa module from Amazon is documented here – along with specifications for the “AT commands”.  The board-mount module that it’s based on is the RYLR890 which is documented here.

The MicroChip (formerly Atmel) LoRa offerings are also interesting.  There is the R34, a low cost BGA SoC that has a 32 bit ARM plus a multi-band LoRa radio.  It’s available on the cool DM320111, a US\$99 reference design / development kit, also available from Amazon for the same price.  One concern is that the documentation talks about the LoRaWAN protocol stack, which we’d want to turn off, so we can just talk simple serial from station to station.

Then I found the Hope RF series of LoRa modules, very interesting, especially the RFM95W.  It looks like it’s just what we need.  It does simpler modulation as well, just by flipping a bit in its configuration.  You would lose all the error correction hyper sensitivity, and built-in spread spectrum, but it would be an easy way to establish simple communication. There seems to be plenty of documentation on the chip, the RF95.  If you Google “HopeRF RF95”, you will find RFM95_96_97_98W.pdf on the SparkFun web page, which gives comprehensive documentation of the chip, its operation, and its registers.  I suspect SparkFun stocks, them, and Digi-Key has them as well.  There appears to be a nice Demonstration Kit, the RFDK_RFM95, but I can’t seem to find a vendor…  GorillaBulderz in Australia lists them but has no inventory, and no indication of when it will be in stock.