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I’ve typically questioned concerning the secret lifetime of my cats.
Properly, not a lot my present ones — they’ve a heady way of life of consuming and sleeping, often venturing outdoors to dream of catching a squirrel.
Earlier feline members of the family have spent days away from house, and who is aware of what they bought as much as. A second household? Having a go on the feral way of life? Your guess is nearly as good as mine!
I am going to by no means know the place they wandered to, however I would be capable to determine it out with future fuzzballs because of Gerhard Peter (@katzentracker) and the unbelievable miniaturization of know-how that permits for such designs because the Katzentracker GPS LoRa monitoring board, which we will have a look at in the present day!
Katzentracker?
German for cat tracker, this mission goals to place an finish to the thriller of the place the moggy has gotten to, by squeezing GPS, and accelerometer, MCU and LoRa long-range radio right into a tiny 30mm coin, purr-fect for attaching to your pet’s collar!
The birds eye view of the Katzentracker board format.
That is no small feat. The factual matter is that there’s not likely even sufficient room to correctly design a LoRa antenna format in a 30mm disc. After which there’s the remainder of the circuitry to cram in! Let’s check out what is going on on right here!
Make mine a module, please…
The host MCU on this platform is the Microchip SAM R34 — a 32-bit Cortex-M0 much like the SAM D21 MCU, but in addition packing a Sub-GHz radio transceiver. This permits it to transmit and obtain on LoRa-modulation scheme wi-fi networks (LoRaWAN), equivalent to TTN — good for an answer the place you count on gateway protection.
TTN Gateways close to my location.
The above map would possibly look considerably sparse, however we have to keep in mind that LoRa is “lengthy vary” — as much as a number of km in city environments is feasible, and line of sight hyperlinks as much as 15km in open areas are typical!
And the place as many people would possible select to design in a module, moderately than a discrete SiP implementation, the Katzentrakcer additionally does simply that, in electing to make use of a module supplied by Embit — the EMB-LR1276S.
Having laid out a earlier, equally sized mission — RF is just not enjoyable at that board scale, and something that may take away from the nightmare of the antenna design alone is a blessing — so extra modules please!
It is nice to see the SAM R34 once more — we have taken a have a look at it beforehand with the BastWan boards from Digital Cats. These boards additionally use a modular answer for the R34, this time the RAK4260 from RAK Wi-fi.
Modules actually do make issues a bit simpler to handle all spherical!
The BastWan LoRa Feather board.
This group additionally kindly launched an Arduino Core board assist package deal for the R34 SiP, full with working code and examples that exhibit the usage of the LoRa radio entrance finish!
All the things is an antenna. The magic is in designing one which works…
Getting a LoRa tuned antenna into such a small area takes some doing, and a few intelligent engineering from the antenna producers. We are actually seeing ceramic packaged components that pack the entire magic and voodoo that makes a great antenna into ever smaller and smaller footprints.
A ceramic SMD loop antenna.
With a Pulse Larsen half chosen that not solely has a small footprint, however an area optimized and forgiving floor aircraft format related to it, designs equivalent to this tracker are actually attainable, with out going off spec!
For comparson, right here is the format required for the same half from a distinct producer. Notice that this half even requires an exterior hint to finish the antenna, which must also have an related floor aircraft, as proven under.
That is lots of actual property!
Elements like this do not fare effectively for small PCB layouts, so we have now to offer a nod to Peter for locating such an appropriate half for this mission!
A tiny tracker wants a gnat-sized GPS…
Everyone knows how GPS works, however we would not all be so conscious that you would be able to now get a GPS module full with patch antenna, which can fortunately sit on the top of your fingertip!
The Micro Hornet (ORG1410) from Origin GPS is actually tiny — they declare to be the world’s smallest GPS module!
I used to be not even conscious you could possibly get GPS antennae down at this scale, so a module with built-in antenna that’s 10mm² is actually spectacular to me!
Step counting is not only for people, oh no!
With a minute, 2mm² footprint, the BMA400 tri-axial accelerometer from Bosch Sensortec enables you to monitor your motion throughout three axes, whereas merely sipping on energy, and slipping into the smallest slice of board space.
This MEMS half quotes 3.5μA present consumption (“common use case”), step counting performance at 4μA and as little as 800nA in deep sleep mode! Not solely small on area, but in addition mild on the facility finances!
Final time we noticed this half pop up was in a equally miniature sized, module-based ESP32 powered system, the Open SmartWatch mission — from pauls_3d_things — which we lined final yr.
Talking each I2C and SPI, it is a nifty half to remember for when board area is at a premium.
Transferring foward…
Whereas the Katzentracker mission is not open supply, we have taken a have a look at the modular strategy to the design, and hope that the observations would possibly assist information others who may be considering fabricating their very own femto-sized feline trackers — or software derivatives thereof!
If you need to take a better have a look at the Wiki for this mission, it may be discovered right here!
Katzentracker is on Twitter, the place future updates will possible be discovered.
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