💬 Sensebender Micro mk2

[Ptibu]

@tbowmo
Another big advantage of the SAML over the SAMD is the embedded AES core. It would allow strong crypto for both comm & data encryption (at MCU level, not radio) and authentication (ex: AES based CMAC). In this case, the ATSHA is not needed anymore for auth but it will break compatibility with existing ATSHA based boards (unless implementing SHA256 in SW).
For what I can see, cost for SAML is about the same than SAMD + ATSHA (+/- 0.5€).

For new (secured) mysensors networks, SAML would have nice advantages with comparable price (+dev efforts of course).

[scalz]

@Ptibu
I'm also using some custom atsamd boards on my side. I looked a while ago at SAML. They have some some common points, but if i remember SAML datasheet, it's not completely the same, especially for low power modes, additional features etc.. Is SAML Arduino compatible now? i'm just curious, i don't really need it as there are already so much other great mcu or complete module :)

[Cliff Karlsson]

Is there any site where you can upload the pcb+bom and have all the components (maybe not radio and pinheaders) soldered before they send the pcb?

[Ptibu]

@scalz said:

Is SAML Arduino compatible now?

Not yet. but it is WIP
https://github.com/arduino/arduino-builder/issues/176#issuecomment-269110984

@Cliff-Karlsson said:

Is there any site where you can upload the pcb+bom and have all the components (maybe not radio and pinheaders) soldered before they send the pcb?

It is called PCBA service. dirtypcbs and itead have such services.
Got price estimation from itead few weeks ago for this board: about 550$ / 10 boards, including PCD ~100$, stencil ~60$, components ~219$ and assembly ~150$)

[tbowmo]

@Cliff-Karlsson @Ptibu

You can order the board from our partner itead studio here, with all SMD components mounted. You need to add radio / ethernet module yourself.

[tbowmo]

@Ptibu

Just checked mouser prices, for 100 units:

ATSAML21E18B-AUT : 519,0$

ATSAMD20E18A-AUT : 298,0$
ATSHA204A-STUCZ-T : 83,7$
total : 381,7$

price difference: 137,3$ for 100 boards, or 1.37$ per board. So we can still save a couple of bucks by using atsamd + atsha204

[Ptibu]

@tbowmo OK, for 100 pieces, it makes a huge difference, sorry.
And glad to see the gateway available, good work !

[tbowmo]

@Ptibu

I'm always looking at larger quantities when designing boards :).. Specially when designing the sensebender boards, if we can lower the price just a little it means cheaper boards for the community, or a bit more contribution to the site maintenance etc.

[bjornhallberg]

Any progress on the mk2?

[tbowmo]

@bjornhallberg

I've got the first prototype pcbs for it.. So just need to get components and assemble the first sample. However, the wife thinks that a new chicken coop (which will be filled with sensors :D) , and various other projects, have higher priority :).

[lafleur]

Is this board using the RFM69HCW footprint so that one could also use an RFM95??
If not, please consider this change and you might want to consider as an option for DIO-1 connected to an I/O pin on the CPU.. (this would also make it compatible with LoRaWan network)

Thanks

[tbowmo]

@lafleur

I used the standard RFM69W footprint at the moment. This is because I do not need the high power variant, that the RFM69HCW is (it is more power hungry as well)

Things can still change...

[lafleur]

Both the RFM69HC and RFM69HCW are available in the smaller package.... again, this would allow RFM95 to be used.

Thanks...

[0_1496601875842_RFM69HC_DataSheet_v1.1.pdf](/assets/uploads/files/1496601877634-rfm69hc_datasheet_v1.1.pdf) 

[tbowmo]

@lafleur but doesn't the H denote a high power output device? Which means higher power consumption.

[lafleur]

Yes, The H = High Power version, C = Compact version 16x16mm pkg, vis 16x19mm pkg

My error, RFM69CW and RFM69HCW are available, also note that if you do not use the power over +13dbm, power consumption is about the same between the radios.

https://lowpowerlab.com/forum/rf-range-antennas-rfm69-library/rfm69w-and-rfm69hw-current-consumption/


[0_1496604219131_RFM69CW-V1.1.pdf](/assets/uploads/files/1496604221362-rfm69cw-v1.1.pdf) 

[tbowmo]

@lafleur

RFM69CW and RFM69HCW are not pin compatible.. One downside with hoperf, that they can't stick with a standard footprint layout..

[lafleur]

Well, that news to me. I've always use the HCW variant and did NOT noticed the pin change. My error for not looking at the detail... (This was not the case with the RFM69W and HW radios, both shared the same pin-out)

but again, using the HCW allow one to also use the RFM95 radios, and if you keep power below +13, power consumption is about the same... also the new RFM69 radio driver in 2.2b use adaptive power control as an option, this keep power use to a minimum saving power.

I just re-checked the data sheets, RFM95 and RFM69HCW do share the same pin-out.

[mfalkvidd]

@tbowmo from what I understand, they are pin compatible.

C and "non-C" are not pin compatible, but H and "non-H" are.

Older discussion on a similar topic: https://forum.mysensors.org/post/60304

[tbowmo]

@mfalkvidd

Check the datasheets, RFM69HCW has 16 pins, while RFM69CW only has 14 pins.

At least when I looked at the datasheets a couple of hours ago

[tbowmo]

@lafleur

Seems that you are right about the power consumption.. According to the datasheets, they use the same in receive mode, and when transmitting 13dBm.. So in theory it shouldn't do any harm on battery life..

Well I'll see if I can incorporate it in the second prototype..