Sensebender Micro

[gloob]

Are there any recommendations for a low power temperature, humidity sensor regarding the update cycle.

Currently I plan to wake up the sensor each 10 minutes instead of each 1 minute to update the values. This should increase the duration of the battery. A complete update of all values if performed each 30 minutes as usual.

[tbowmo]

I would probably choose 5 minutes interval instead.. I have updated the sensebendermicro sketch tonight (just waiting for @hek to approve it). so it holds of on the transmissions a bit. Now the temperature needs to change more than 0.5 degrees from the previous transmitted value. OR
humidity needs to change more than 0.5, measured with a moving average. OR
30 minutes since last transmission.

[gloob]

I found that when I power the micro from 2 batteries I get the following error:

T: 23.21
H: 50
send: 104-104-0-0 s=1,c=1,t=0,pt=7,l=5,st=fail:23.2
send: 104-104-0-0 s=2,c=1,t=1,pt=2,l=2,st=fail:50

This does not happen when I power it from the FTDI programmer.
Does anybody have any ideas?
The batteries have a voltage of 3.25V

I did not have this issues with my arduino nano sensors. and i did use the same radio modules.

When I check the modules they seem to be real nrf24l01+ modules:

STATUS		 = 0x0e RX_DR=0 TX_DS=0 MAX_RT=0 RX_P_NO=7 TX_FULL=0
RX_ADDR_P0-1	x00 = 0xe7e7e7e7e7 0xf0f0f0f0d2
RX_ADDR_P2-5	x00 = 0xc3 0xc4 0xc5 0xc6
TX_ADDR		 = 0xe7e7e7e7e7
RX_PW_P0-6	x00 = 0x00 0x20 0x00 0x00 0x00 0x00
EN_AA		 = 0x3f
EN_RXADDR	x00 = 0x03
RF_CH		 = 0x4c
RF_SETUP	x00 = 0x07
CONFIG		 = 0x0f
DYNPD/FEATURE	x00 = 0x00 0x00
Data Rate	 = 1MBPS
Model		 = nRF24L01+
CRC Length	 = 16 bits
PA Power	 = PA_HIGH

[Fabien]

I have a batch of 5 sensebender and actually I build 3 and one of them doesn't work properly. Lot of st:fail when I put my finger on the board it works better so I try to make all solder one more time but it's not ok. I try with few radios and same radios work well on the others sensbender.
Any idea or way to exchange with Itead ?

[tbowmo]

@Fabien

Where exactly do you put your finger on it, in order to get it working?

[tbowmo]

@gloob

It's the same power rail (FTDI, and the battery connector). What do you supply the board with, thru the FTDI header?

[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 ...