Sensebender Micro

[Anticimex]

@ximinez makes sense. I'm sure you can cut down on power consumption by cutting power to those peripherals. I do not know how signing would be affected by this though, as I have not tested it with switching the atsha on and off between calls. I would like to hear from you on that topic if you choose to try it though :)

[ximinez]

Ok, I've been looking at the image and my spare sensor. It looks like:
Power to the NRF can be cut between C3 and VCC pin.
ATSHA204a power can be cut on the trace that goes from the atsha and beneath the flash.
Si7021 power can be cut at the trace that goes from C4.

I just might have to dig out my scalpel and iron for this. If the components magically work without any extra initialization on powerup, modifying the code looks easy.

I'll report back with my findings

[tbowmo]

@ximinez

For my battery reporting, I have set 1.9V as 0%, 3.3V is 100%..

While you're at it, also power down the external flash, as it might also contribute a bit..

[ximinez]

Well that went south pretty fast. Was wondering why my sensebender was acting up. Took a while to see that I had plugged in an ESP8266 module instead of one of my NRF24 modules. Those modules look far too much alike :rage:

Serial output now looks like this: "Sånsebåndåò Micro FW 1.3" with random characters corrupted. I think I've killed it ;)
I can still flash firmware to it via serial, so it's not completely dead.

I can however confirm that both the SHA204A and SI7021 self-tests OK being powered on in-sketch:
(Flash seems to randomly fail or test OK, not sure why yet)

þSånseâånder Micòo F× 1.3 - TesôÍoäe
Tåstiîg påòipheraló!
-> ÓÉ7021 : ok!
-> Æìasè : æailed!
-> SÈA204 : Ïk (seòéal : 01234ÂBAÅ259E8AÄÅE)
Tåót fiîésheä
----> Óelftest æaiìåä!

[Anticimex]

@ximinez If possible, try to check if signing and verification of signatures work as well. I have tried to implement the use of the ATSHA to be atomic in nature, but it could be that some state is retained which is cleared on power down which might break the calculations.

[ximinez]

What is the easiest and fastest way to sign and verify? I don't have a gateway set up quite yet.
(And, is any part of setting this up dependent on serial integrity? If so I might have to adjust baud quite a bit)

[Anticimex]

@ximinez Well, without a gw the only option is to use node peer to peer transmissons to test signing. How to do it is described in the signing documentation, assuming you use development branch, you can see here. For master, look here.

[ximinez]

I have an Uno with an ethernet shield and nrf24 hooked up, so I will have to get around to write a sketch for that purpose.
But to get signing to work, I'll have to personalize the atsha? That sketch doesn't compile for me.

[Anticimex]

Yes, you have to personalize it. What is failing? I don't have an Uno myself, but according to Jenkins the personalizer compiles ok for Uno on both master and development. You don't have any local changes?

[ximinez]

The personalization fails to compile for my sensebender micro. There's a few undeclared:

Personalizer:225: error: 'EEPROM_SIGNING_SOFT_HMAC_KEY_ADDRESS' was not declared in this scope
Personalizer:225: error: 'hwReadConfigBlock' was not declared in this scope
Personalizer:236: error: 'EEPROM_SIGNING_SOFT_SERIAL_ADDRESS' was not declared in this scope
Personalizer:247: error: 'EEPROM_RF_ENCRYPTION_AES_KEY_ADDRESS' was not declared in this scope
Personalizer:697: error: 'hwMillis' was not declared in this scope

I'm trying to compile this against master however. Do I have to have dev branch to compile that sketch?

[ximinez]

Fails with the same errors on Uno for me.

[Anticimex]

@ximinez and you are certain you have no local changes to the code? Jenkins builds both master and development branches every night for both the SenseBender and the uno and it builds all examples, including the personalizer without issues.

[ximinez]

Pretty sure.
I'll wipe my library dir and redownload master.

[Anticimex]

If memory serves me, some of the errors you get seem to originate from code on development branch. The eeprom addresses are to my knowledge not yet available on master.

[ximinez]

Ok, moved from master to dev. Sketch compiled. Not quite the output I expected however.

EEPROM configuration:
SOFT_HMAC_KEY | FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
SOFT_SERIAL | FFFFFFFFFFFFFFFFFF
AES_KEY | FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF

[Anticimex]

@ximinez it is the output I expected. You have gone for soft signing, and you see the reset values of the eeprom. You need to pick atsha settings. The link I gave you gives the exact settings to personalize both for software and atsha backends.

[ximinez]

Got it now :)
I had two different sketches and had edited the wrong one. Now I have actual values.
Is there an example GW sketch that I can load quickly to my Uno/W5100 shield/NRF24?

[Anticimex]

:thumbsup:
I'm rusty on the gateways. But on development branch, configuring signing is easier than on master branch. My link gives the details on signing configuration for both nodes and gateways with examples.

[ximinez]

Yeah, I'm struggling a bit with those instructions. I've set up my gateway with soft signing, and got sane values written to EEPROM.
Now, do I need any of the three values to personalize the sensebender?
SOFT_HMAC_KEY?

[Anticimex]

@ximinez the SenseBender you have patched/cut needs atsha personalization, so no SOFT anything. But you need to have the same hmac key stored on the atsha on the SenseBender as you have picked as soft hmac key in eeprom of your gateway (the node you have personalized for soft signing).