Author Topic: Low Power consumption with stock Moteino  (Read 5884 times)

overlord

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Low Power consumption with stock Moteino
« on: September 16, 2016, 01:22:55 PM »
Hello,

I'm searching for an example sketch which has the lowest possible power saving with stock Moteino without removing the regulator.
Is MoteinoMote good for that requirement or are there more powersaving sketches?
https://github.com/LowPowerLab/RFM69/blob/master/Examples/MotionMote/MotionMote.ino
My sensors will only send signals every 5 minutes (Temp, Humidity, Pressure with BME280, sensors supply will be switched off in sleep mode)
What would be the optimal battery for the LDO - 2xAA or a 9V Lithium Block to have the lowest possible power consumption when in deep sleep mode?
I'm only searching for an example sketches which is sending something with the lowest power possible.

Thanks in advance,
René

Felix

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Re: Low Power consumption with stock Moteino
« Reply #1 on: September 16, 2016, 01:34:36 PM »
See the DeepSleep examples.
This should give you ~6.5uA on a stock barebones Moteino (with radio, flash put to sleep). Any other sensors you have also have to sleep. The BME280 has to be put to sleep specifically or it will drain a lot of current.

overlord

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Re: Low Power consumption with stock Moteino
« Reply #2 on: September 16, 2016, 01:44:03 PM »
Hi Felix,

thank you what Battery you would recommend in that setup?

Best Regards,
René

Felix

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Re: Low Power consumption with stock Moteino
« Reply #3 on: September 16, 2016, 01:50:28 PM »
For testing it doesn't matter. Keep it above 3.6v otherwise the regulator will be in the dropout region and use a lot of current.

Battery choice is a broad subject and what battery you choose depends on the application where you use that battery.

overlord

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Re: Low Power consumption with stock Moteino
« Reply #4 on: September 16, 2016, 02:12:29 PM »
I looked on the deep sleepe examples, but they contain no transmission code only the power management in loop() function.
would the additional lines after LowPower.powerdown() call work? Initialize Radio, flash, encryption, send?
Code: [Select]
void loop () 
{
  ..........
  //sleep MCU for 8seconds
  LowPower.powerDown(SLEEP_8S, ADC_OFF, BOD_OFF);
  //after awake turn on flash and radio
  radio.initialize(FREQUENCY,NODEID,NETWORKID);
  radio.encrypt(ENCRYPTKEY);
  radio.sendWithRetry(GATEWAYID, buff, buffLen)[/color]
  //turn radio off again?
 
}


overlord

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Re: Low Power consumption with stock Moteino
« Reply #5 on: September 16, 2016, 02:23:24 PM »
OK the Mailbox example has everything I need combined with the lowpower sketches.
https://github.com/LowPowerLab/RFM69/blob/master/Examples/MailboxNotifier/MailboxNotifier4_sender.ino
I will post my examples on github when I'm done with it.

Felix

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Re: Low Power consumption with stock Moteino
« Reply #6 on: September 16, 2016, 02:24:09 PM »
You asked for "the lowest possible power saving", so those sketches do just that, they give you a starting point.

See other examples how to achieve radio sending modes and sleep. A good one is the MotionMote example which includes BME280 code to read/sleep the sensor.

ChemE

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Re: Low Power consumption with stock Moteino
« Reply #7 on: September 17, 2016, 09:31:45 AM »
Overlord, grab a few TPL5110 boards to play around with they are totally insane.  I've got a mote sensing temperature and RH every 60 seconds and sending a 3-byte payload at 300kHz back to my gateway.  It is awake for 13ms every 60 seconds and thanks to the TPL5110 my two AA batteries will last 300 years!  I know I'm neglecting self-discharge but for projects that can be full off between work the TPL5110 is just amazing.  I measure 38-39nA inclusive of the MOSFET.  Current that low makes sleep irrelevant.  I cannot wait for Felix to offer Motes that replace the LDO with the TPL5110 instead.

EDIT: Forgot to address your battery question; 2 L91s or L92s from Energizer appear to be the absolute perfect choice for maximum battery life.  You avoid the 2 microamp drain of the LDO.  Pair that with a 39nA sleep current of the TPL5110 and you can "sleep" the project for 9,945 years.
« Last Edit: September 17, 2016, 09:45:58 AM by ChemE »

MoebiusL

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Re: Low Power consumption with stock Moteino
« Reply #8 on: September 29, 2016, 10:22:54 PM »
Hi ChemE,

I never used the TPL51110 and I'm looking for alternatives to run projects using one or two AA/AAA cells, at the moment testing some "whisper nodes", but would be much happier with 40nA you're getting! As far I understand it turns the whole circuit on and off based on a adjustable timer, correct? So you always "boot" your board instead of sleeping it, losing all memory?

Another question is how does it helps with the 2xAA batteries? wouldn't the battery voltage, 2 AA gives you only 3V and not 3.3V. Also, wouldn't the voltage start to drop below an acceptable level after while?

Very interested in your results!!!

ChemE

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Re: Low Power consumption with stock Moteino
« Reply #9 on: September 30, 2016, 08:11:44 AM »
That is correct, the TPL5110 cuts all power to the microcontroller so any data which needs to persist would either need to be stored in EEPROM or in the TPL5110's 256bytes of RAM which is retained with the scant 38-39nA of my circuit.  One of several advantages of the lithium batteries that I am using is they have a higher voltage than do rechargables and alkalines.  Virtually all of their power is available between 1.7V and 1.4V which means you can skip any LDO and BOD since you are guaranteed to have safe voltages until they die totally.  Two AA or AAA lithiums seem to be tailor made to run a Moteino.  They also have such a low self discharge rate that they should last 20 years as long as your circuit doesn't consume too much.  Moteninos with the RFM69W are happy to run down to 1.8V.  The RFM69HW's have a switch which needs 2.4V but either way, two L91s or L92s will satisfy the voltage needed until end of life.

Regarding the boot sequence, I am going to start fooling with using a 328p with no bootloader so that delay is eliminated and I also plan to mess with the fuse settings to try to get the chip up as quickly as possible.  I don't have an oscilloscope so I cannot measure the duration/current during this period.  I should also note that I've adjusted my program so that the processor asks for a no hold temperature reading and then sleeps for 15ms and then wakes, reads the result, asks for a no hold humidity reading and sleeps another 15ms.  This increased my projected battery life to 900 years.  Now the processor is only awake for 300 microseconds + the radio transmission which is very brief being 3 bytes of data at 300kHz.
« Last Edit: September 30, 2016, 03:48:31 PM by Felix »

TomWS

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Re: Low Power consumption with stock Moteino
« Reply #10 on: September 30, 2016, 10:24:06 AM »
...any data which needs to persist would either need to be stored in EEPROM or in the TPL5110's 256bytes of RAM which is retained with the scant 38-39nA of my circuit.
I suspect you're confusing the TPL5110 (which has no RAM and no interface to access it if if did) with the AM18x5 RTC chip which does have 256bytes of RAM and it has about the same power consumption, but necessarily more complex interface and software to control it.

The beauty of the TPL5110 is it's simplicity - easy to solder packaging and trivial software requirements.  One possible downside, depending on your needs, is that it is a fixed interval sequencer - time starts when the power is applied and will continue at that fixed interval forever.

Tom

ChemE

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Re: Low Power consumption with stock Moteino
« Reply #11 on: September 30, 2016, 10:58:30 AM »
Thanks Tom, I've been spending too much time in datasheets lately it seems!

WhiteHare

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Re: Low Power consumption with stock Moteino
« Reply #12 on: September 30, 2016, 11:40:21 AM »
That is correct, the TPL5110 cuts all power to the microcontroller so any data which needs to persist would either need to be stored in EEPROM or in the TPL5110's 256bytes of RAM which is retained with the scant 38-39nA of my circuit.  One of several advantages of the lithium batteries that I am using is they have a higher voltage than do rechargables and alkalines.  Virtually all of their power is available between 1.7V and 1.4V which means you can skip any LDO and BOD since you are guaranteed to have safe voltages until they die totally.  Two AA or AAA lithiums seem to be tailor made to run a Moteino.  They also have such a low self discharge rate that they should last 20 years as long as your circuit doesn't consume too much.  Moteninos with the RFM69W are happy to run down to 1.8V.  The RFM69HW's have a switch which needs 2.4V but either way, two L91s or L92s will satisfy the voltage needed until end of life.

Regarding the boot sequence, I am going to start fooling with using a 328p with no bootloader so that delay is eliminated and I also plan to mess with the fuse settings to try to get the chip up as quickly as possible.  I don't have an oscilloscope so I cannot measure the duration/current during this period.  I should also note that I've adjusted my program so that the processor asks for a no hold temperature reading and then sleeps for 15ms and then wakes, reads the result, asks for a no hold humidity reading and sleeps another 15ms.  This increased my projected battery life to 900 years.  Now the processor is only awake for 300 microseconds + the radio transmission which is very brief being 3 bytes of data at 300kHz.

Have you measured the wake-up time and current consumed going from a complete powered-down state to a powered-up-and-ready state?  Unless your sleep periods are quite long, I think you'll likely find that it exceeds the 250na sleep current plus the current consumed during the 3.8us wake-up-from-sleep time.

ChemE

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Re: Low Power consumption with stock Moteino
« Reply #13 on: September 30, 2016, 01:26:49 PM »
I have not measured that b/c I don't have an oscilloscope.  I've searched rather extensively online and cannot turn up this missing information either.  I do agree that this is an important piece of information to using the TPL5110 or AB1815 correctly though.

TomWS

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Re: Low Power consumption with stock Moteino
« Reply #14 on: September 30, 2016, 04:29:37 PM »
Thanks Tom, I've been spending too much time in datasheets lately it seems!
I here ya!  Easy to get lost when you're looking dozens of different devices.  You know that ONE of them has this key feature, but which one was it???   :)