Sensebender Micro

[Fabien]

@tbowmo difficult to answer this question. It seems to be on Atmega but after trying to resold it's not better. I resol capacitors, resistors ... I don't know what to do now ...

[tbowmo]

@Fabien

Did you also resolder the atmega itself?

Could you try and measure supply current it uses?

[Fabien]

current when powering on : 20 mA and during sleeping about 20uA (not very accurate).

[tbowmo]

@Fabien

Have you tried to add an extra capacitor to the NRF module, on the one that's bad? (Could be your finger adds a bit more capacitance, I know it's a wild guess but just trying to think out loud)

[Fabien]

Ok but wich value ? I just finish to solder my 4th sensebender and ok too.

[hek]

Does the failed messages reach their destination (gateway in your case)? As you might know it is the ack that never reaches the sensbender node which could be a result of power issues on the gateway side.

[Fabien]

no, message are not recieve. I find someting :
When I touch the NRF24 antenna (just a little it sifficient), it works. fine.
Strange, same radio on other sensebender doesn't need this and other radio on this sensebender need to bo "touch".
I try with 10uF additionnal on NRF but no change ...

[hek]

Do you use a socket or is the NRF module directly soldered onto the sensbender?

(a bad connection in socket could be a problem... and when you press NRF module it has connection again)

[Fabien]

Yes it's directly sold (and very hard to change with metallised hole). I will give a last try with another radio ...

[Fabien]

Ok end of story ... sensebender card is dead ! 2 metallized hole were destroy by solder/unsoldering NRF modules.
Hope my last Sensebender will work. And if there is a batch with light version I will reuse T/H sensor

[gloob]

@Fabien it seems that you have the same problem as me. I ordered a new set of radio modules to test if it is the fault of the radios. I will give feedback here about my progress.

I aleady tried to add capacitors on the radio module but this did not help.
There is also no difference if I power the micro from the FTDI or the battery connector.

[tbowmo]

@Fabien

Unfortunately I don't think there will be a light edition coming out at the moment. Currently the savings is way too small (I'm estimating a savings of 4-5$ compared to the full sensebender edition).

[hek]

@Fabien

Here are some quite nice repair guides
http://www.circuitrework.com/guides/guides.shtml

More specifically
http://www.circuitrework.com/guides/5-1.shtml

[Fabien]

@gloob it's not a radio problem. Same radio works on the others boards.
@hek I will try to repair the board ...

[mvader]

looking for some help programming this thing.
I had a pl2303 usb programmer, but it had no DTR, so i orders a new usb programmer
this one is a cp2102 with a DTR line.
but still the same problem. it never uploads the code.
i have the right board, processor and port chosen.
i have tried all the programmers in the IDE but none work.
it just says "uploading" and then eventually errors out.
any suggestions?

EDIT: nm i read something about switching tx and rx and i figured what the heck and surprise it worked..
sketch uploaded..

[tlund]

Hi @tbowmo

Thanks for bringing this great project to the community.

I'm trying to understand the sensebender's power profile, especially the sleep current.

I have previously done some measurements with the atmega328p (pro mini) + NRF. In addition to that I have also looked at the datasheets for the other components on the sensebender.

It seems the theoretical low sleep current consumption is something like this:

* nrf24l01+    900nA
* atmega328p     5uA (with WD)
* si7021        60nA
* atsha204      30nA
* at23df512c   300nA
  =  Total     6.3uA

The SBMicro seems to draw ~50uA in sleep mode with the default configuration.

I managed to put the flash memory into "ultra deep sleep"(*), causing the total consumption to drop to ~27uA. So there is still around 20uA that is not accounted for.

I've also tried putting the atsha204 into sleep, but that did not make any difference (also confirmed by the specs).

Are there some other settings/sleep modes that have not been enabled yet? What about the atmega itself?

Do any of you have the a sensebender prototype with separate components, and can test sleep current by removing components one
by one? (Before I start cutting traces on my own sensebenders in order to zero in on the target component).

Is there something I'm missing?

Datasheets:
ATSHA204
AT25DF512C
Si7021 A20

(*) in setup(): flash.initialize(); flash.ultra_deep_sleep() <- From datasheet

[tbowmo]

@tlund

Interesting figures.. are you sure that you've got a genuine nrf24 chip on the radio? Could be a fake with higher power consumption.

[tlund]

@tbowmo

My NRF's are the same $1 nrf's listed in the mysensors store, so probably fake. But I have still measured them to draw ~900nA in powerDown.

But I think I have found the culprint now. It seems the extra 20uA is caused by Arduino 1.6.5 (it may be that my installation is faulty).

My test setup:

• pro mini
• nrf
• a simple sketch that does gw.sleep(60s)

1st test: sketch compiled & uploaded via Arduino 1.0.5-r2: 6uA
2nd test: sketch compiled & uploaded via Arduino 1.6.5: 24uA

[tbowmo]

@tlund

Hmm could it be some optimization that causes the atmega to not go into deepest sleep mode?

Maybe someone should have a look at the assembler output from a build with both versions of arduino

[Fabien]

I'm back with bad news ... My 5th sensebender have a lot of st:fail like the first one. But now I know why !
There is only one same things between the two board which fails : The FTDI connector. It's 90° connector and pins are just below the antenna. And I think tunning is not ok.
So, when I go to work I try to remove the FTDI connector and see if connection is better !