Low Power: How much current? [Solved]

NeverDie

I have an O-scope just dont know how to use it completely lol. Leaving work now. Stayed extra 2 hours to play with power settings lol

@NeverDie did you still need me to write up what I did or you followed it pretty much?

I'd prefer to have a nice consolidated write-up for two reasons:

So I can be sure I'm following it right. If I do it differently, then any measurements I might get won't do you much good, if any. And,
So others, including noobs, can follow along to both understand it as well as replicate it for themselves, because then you leverage the true power of open source. It's well proven: the mores eyes on something, the better it gets, and the more everyone benefits from the experience. For that to work, the clearer the "something" is, the better. The more details the better too.

OK, finished editing. :smile:

brolly759

I keep watching you edit your post, its freakin me out! lol

scalz

@Neverdie @brolly759 : I will follow your progress with interest and help if I can. For the moment, I have a lot of work before playing with my uCurrent. And for respect for Charles work, I am waiting his release. But when I will receive my boards (at then end of the month), if lib is not released yet, I will clean my code. And don't forget, I am using boosters and mosfets, so it is different. but roads are crossing of course. with booster what I like is, I will have 3.3v vcc during the whole battery life too.
Too late for me! 2am, lol. time to powerdown. See you soon:smiley:

brolly759

Running Arduino+NRF24l01 w/ interrupt consuming 1.5uA in sleep

I am using this Arduino Nano Pro 8mhz 3.3v :link text
I am using this NRF chip: link text

Here is my test environment:

Arduino Nano with desoldered jumper for bypassing voltage regulation (If you dont have bypass jumper on the knock off Nano, look at this post: link text )
NRF connected via pinout on MySensors guide
3V direct supply from 2 AA Batteries
uCurrent Gold testing voltage current
Fluke 179 reading in mV
Using the BinarySwitchSensor sketch in the MySensors library

If I upload the sketch as is with the recommended setup guide, Pin 2 or 3 is an interrupt pin and that goes to GND and acts as a switch. Pin 2/3 is HIGH and uses the internal pull up resistor. We will refer to the 2 different states of the switch as follows:

"oState" (Open, when Pin 2/3 does NOT touch GND)
"cState" (Closed, when Pin 2/3 touches GND)

When running everything I get these sleep numbers:
oState: 23-24uA
cState: 117uA

I downgraded my Arduino IDE from 1.6.5 to 1.0.6 and here are my new numbers:
oState: 2.5-2.7uA
cState: 98-100uA

Everything is looking good but my cState is still too high for any battery applications that I am trying to get.

Removed digitalWrite on pin 2/3. Connected 10M resistor from pin 2 to VCC. GND is switch to pin 2.
oState: 2.5-2.7uA
cState: 3.1-3.2uA

Reference measurements:

At this point I ran the "DallasTemperatureSensor" to test current using the WDT, I did NOT connect Temp sensor
Sleep current with WDT enabled @ 30 seconds: 7.6-7.8uA

Using "BinarySwitchSensor", remove NRF completely and only have Arduino:
Sleep current: 110-120nA OR .4-.5uA (had issues reading this but I believe it is the nA)

Connecting VCC/GND only to NRF to read standalone current:
NRF only: 800-900nA Shutdown current

Useless numbers while running the BinarySwitchSleepSensor sketch:
Sleep current: 2.7-2.9uA with NRF/Arduino fully connected
Sleep current with nRF GND disconnected: 1.7uA
Sleep current with nRF VCC and GND disconnected: 294nA
Sleep current with nRF VCC/GND/Pin9 disconnected: 281nA
Sleep current with nRF VCC/GND/P9/P10 disconnected: 196nA
Sleep current with nRF VCC/GND/P9/P10/P11/P12/P13 disconnected: 110-112nA
Sleep mode with ONLY Arduino: 110-112nA
NRF plugged into VCC/GND only: 800-900nA

At this point we are getting 2.7-2.9uA with Arduino/NRF. Stock MySensors library and Arduino 1.0.6 IDE. ( I am using the BinarySwitchSleep Sketch from MySensors lib)

To get even lower power....

Open up mysensors.cpp with NotePad++ application
Look for this code:

bool MySensor::sleep(uint8_t interrupt, uint8_t mode, unsigned long ms) {
    // Let serial prints finish (debug, log etc)
    bool pinTriggeredWakeup = true;
    Serial.flush();
    RF24::powerDown();
    attachInterrupt(interrupt, wakeUp, mode);
    if (ms>0) {
        pinIntTrigger = 0;
        sleep(ms);
        if (0 == pinIntTrigger) {
            pinTriggeredWakeup = false;
        }
    } else {
        Serial.flush();     
        LowPower.powerDown(SLEEP_FOREVER, ADC_OFF, BOD_OFF);
    }
    detachInterrupt(interrupt);
    return pinTriggeredWakeup;
}

We are going to add this code:

SPI.end();  
    for (byte i = 9; i <= 13; i++)
    {
    pinMode (i, OUTPUT);    
    digitalWrite (i, LOW); 
    }  // end of for loop

The final code should look like this:

bool MySensor::sleep(uint8_t interrupt, uint8_t mode, unsigned long ms) {
    // Let serial prints finish (debug, log etc)
    bool pinTriggeredWakeup = true;
    Serial.flush();
    RF24::powerDown();
    attachInterrupt(interrupt, wakeUp, mode);
    
    SPI.end();
    
    for (byte i = 9; i <= 13; i++)
    {
    pinMode (i, OUTPUT);    
    digitalWrite (i, LOW); 
    }  // end of for loop

    if (ms>0) {
        pinIntTrigger = 0;
        sleep(ms);
        if (0 == pinIntTrigger) {
            pinTriggeredWakeup = false;
        }
    } else {
        Serial.flush();     
        LowPower.powerDown(SLEEP_FOREVER, ADC_OFF, BOD_OFF);
    }
    detachInterrupt(interrupt);
    return pinTriggeredWakeup;
}

IMPORTANT: Because you are ending SPI, you will need to call the sensor at the beginning of your loop to reinitialize the NRF

void loop() 
{  
  sensor_node.begin();

Adding both SPI.end(); and for(); loop:
Sleep current: 1.5uA

If you add just the SPI.end();
Sleep current: 2uA

If you just add the for(); loop:
Sleep current: 1.9uA - 2.2uA

If you are using ONLY the "for(); loop", you do NOT need to reinitialize the radio when you come out of sleep. I have noticed a much longer up time when having to reinitialize.

OTHER MEASUREMENTS using the DallasTemperatureSensor with WDT at 30 seconds, no sensor connected:

Edited Sleep with for(); loop:
Sleep current: 6.4-6.5uA

Edited Sleep with for(); loop AND SPI.end();:
Sleep current: (Could not get SPI.end(); to work on sleep(w/WDT))

Quick comment: There are a few sleep options in the MySensors.cpp Depending on which one you are calling will depend on which one you need to edit. Here are some examples of the sleep functions in the .cpp file:

void MySensor::sleep(unsigned long ms)

bool MySensor::sleep(uint8_t interrupt, uint8_t mode, unsigned long ms)

int8_t MySensor::sleep(uint8_t interrupt1, uint8_t mode1, uint8_t interrupt2, uint8_t mode2, unsigned long ms)

NeverDie

@brolly759 said:

When running everything I get these sleep numbers:
oState: 23-24uA
cState: 117uA

I downgraded my Arduino IDE from 1.6.5 to 1.0.6 and here are my new numbers:
oState: 2.5-2.7uA
cState: 98-100uA

Nice write-up!

Is it known why there's a difference in the measurements depending on whether you're using IDE 1.6.5 or IDE 1.0.6? Which IDE version should I use?

brolly759

Someone else complained about the exact same issue here:
http://forum.mysensors.org/topic/1345/sensebender-micro/250

Sparkman

@brolly759 That's a different issue altogether. It's related to measuring battery voltage...

Cheers
Al

brolly759

@Sparkman said:

@brolly759 That's a different issue altogether. It's related to measuring battery voltage...

Cheers
Al

tlund posted 2 months ago reply quote 0
@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

Sparkman

@brolly759 Sorry, I was confused as your link is to post 250 in that thread, which is my post related to measuring battery voltage. What you are referencing is post 191: http://forum.mysensors.org/topic/1345/sensebender-micro/191

Cheers
Al

scalz

@Neverdie : at the beginning, as you were suspicious about the fact I get it. You can see here (look at the dates) that I had problems with low power and Charles helped me.
It's in french sorry : https://community.hallard.me/topic/53/question-à-propos-du-bod/30
At the same time I opened a thread on arduino forum : http://forum.arduino.cc/index.php?topic=336789.0
Another older topic that I solved myself (which contains some part of codes I was testing) : http://forum.arduino.cc/index.php?topic=336329.0
I hope you trust me now. and that I cannot I give a cake which is not finished cooking. I am not hurry. And I prefer the whole thing well packed in a lib, with derivative class, because the less the Mysensors libs are hacked inside, more beautiful it is I think. And then it is easier for users too.

@brolly759 : thank you for writing you results as I have no time for this on my side. Very strange your problem with ide. When I got low power, I was using ide 1.6.0. Maybe I will try 1.6.5 this week end to see, for curiosity. And I know Charles is using 1.6.x too. Another question, is your sensor a binaryswitchsensor only?? In this case, your way makes sense. But if you want to add sensors, you won't be able to keep 1uA without mosfet I think. Maybe I am wrong and you will find a great idea...
I follow your work, no doubt :smile:

NeverDie

@scalz said:

@Neverdie : at the beginning, as you were suspicious about the fact I get it. You can see here (look at the dates) that I had problems with low power and Charles helped me.
It's in french sorry : https://community.hallard.me/topic/53/question-à-propos-du-bod/30
At the same time I opened a thread on arduino forum : http://forum.arduino.cc/index.php?topic=336789.0
Another older topic that I solved myself (which contains some part of codes I was testing) : http://forum.arduino.cc/index.php?topic=336329.0
I hope you trust me now. and that I cannot I give a cake which is not finished cooking. I am not hurry. And I prefer the whole thing well packed in a lib, with derivative class, because the less the Mysensors libs are hacked inside, more beautiful it is I think. And then it is easier for users too.

@brolly759 : thank you for writing you results as I have no time for this on my side. Very strange your problem with ide. When I got low power, I was using ide 1.6.0. Maybe I will try 1.6.5 this week end to see, for curiosity. And I know Charles is using 1.6.x too. Another question, is your sensor a binaryswitchsensor only?? In this case, your way makes sense. But if you want to add sensors, you won't be able to keep 1uA without mosfet I think. Maybe I am wrong and you will find a great idea...
I follow your work, no doubt :smile:

@Scalz Not sure what you're referring to. I've taken what you've said at face value and still do. For the moment, if you are willing and able, it would help Broly759 and me if you would replicate Brolly759's approach (as he detailed above) and see if you can figure out why the IDE version is affecting his measurements. Which measurements are "correct"? Is that something you can help us figure out?

It would be best if we could all use the latest version number when taking measurements, unless there is good reason not to. I'm currently running IDE Version 1.6.5., and to date I haven't had problems with it. I did have some compile-time problems with some of the earlier Version 1.6 releases prior to the 1.6.5 release, but I don't recall now exactly what those problems were.

scalz

ok, I hope I will have enough time this week end because this week I have lot of work too, and Mysensors is jut fun for me. and I am running after time. It doesn't take time to reply for me, more for testings.. but I promise I will try the writeup. And I am trying to create my startup in greentech (automotive, cogeneration.. field) field. So most of my time is dedicated to my project. But I like playing too with arduino, so fun!

One thing I am sure, is when I got 140nA, it was BinarySwitch sketch too, from 2xaaa, ide 1.6.0. Then I added a BS250, to cut off nrf. And I got 140nA again in sleepmode. No problem, for sleep/wake up radio. And of course, I made the same tricks as Brolly in code. But maybe I had luck because I powered it through mosfet. Then I made same thing, BS250, for sensors, and uses BH1750 sketch. I had trouble with i2c. Charles helped me and then I got 140nA again. No problem with radio, sensors... All of this directly from 2xaaa. Then I played with boosters...
I will try brolly's case too, to see if I get same thing.
@brolly759 : you are using an arduin pin to power your nrf, am I right? to be in the same config as yours...

brolly759

GOOD MORNING crazy tinkerer's. Okay here we go again, I am actually going to need someone to verify what I am looking at here, nA and uA are giving me different readings:

Running the "for(); loop" in sleep() function with NRF VCC UNPLUGGED
Sleep current: .8uA - .9uA OR 273nA

Running the "for(); loop" in sleep() function with NRF VCC UNPLUGGED
Sleep current: .6uA - .9uA OR 114nA

@scalz I was powering the NRF directly from VCC. I will play around with connecting it directly to a pinOut on Arduino

brolly759

OKAY so... more numbers to play with... This is Arduino turning on/off NRF using an output pin.

Connect Pin4 to VCC on NRF
Add SPI.end(); and for();loop to include Pin 4 to turn LOW in sleep function

Add this code in define area:

#define WIRELESS_POWER 4

Add this code in loop():

void loop() {
  digitalWrite(WIRELESS_POWER, HIGH);
  delay(5);  
  sensor_node.begin();

Sleep current oState: .5uA - .6uA
Sleep current cState: .8uA - .9uA

@scalz Yes all my testing is on "binaryswitchsensor" sketch. I use the "DallasTempSensor" sketch when I want to test sleep() with a timer. There are SO MANY things you can do with a simple reed switch sensor. Doors, locks, windows, mailbox, fridge, cabinets, drawers... pretty much anything that moves and goes back in a certain place can be used with the "binaryswitchsensor".

NeverDie

@brolly759 When taking your measurements, were you using the current version of the MySensors library (v1.5) or a different one? Are all your other libraries the most up-to-date versions?

You used a Nano Pro, which I don't have. When the red Mini Pro's from Amazon arrive sometime later today, I'll try them.

Unless someone knows of a reason for the different results relating to different IDE versions, I think I will approach this by calling the underlying libraries directly, rather than through MySensors's abstraction layer. That way, if I don't encounter the differences, we'll know that it's a MySensors issue. For example, perhaps something you're setting is being undone by MySensors part way through the process of powering down, or something like that.

scalz

@brolly759 : I am happy for you. I was thinking that you were trying to make a sensor node (not only for binaryswitch). I agree with you for binaryswitch.. I think how you do is right for this purpose. cool. just one thing is with time, your coin cell will not provide full 3v for radio power transmission but it's another story.

See you soon.

brolly759

@NeverDie Good catch, I just checked the version.h file. v1.4.1

#define LIBRARY_VERSION "1.4.1"

In the utilities folder in MySensors library, all the files like RF24.h, LowPower.h are provided by the MySensors library. So I am assuming they were up to date when the MySensors library was created.

@scalz Even though its not full 3.3v it should be fine. The power range for NRF is 1.9v - 3.6v

My next project is to figure out battery monitoring as low as possible. ;) I know there are 2 ways, internal 1.1v reference or voltage divider. Can I do a voltage divider on an output pin and shut the output pin off when not using it?

NeverDie

@scalz said:

@brolly759 : I am happy for you. I was thinking that you were trying to make a sensor node (not only for binaryswitch). I agree with you for binaryswitch.. I think how you do is right for this purpose. cool. just one thing is with time, your coin cell will not provide full 3v for radio power transmission but it's another story.

See you soon.

Actually, your point regarding the coincell not providing full power could be relevant to the measurements (not saying it is in brolly759's case, but I definitely have seen it myself happen with a coincell powered arduino using the NRF24L01+): in cases where the coincell is low, doing a transmission can (because of internal resistance and the much higher current) can cause NRF voltage to drop below threshold, thereby shutting off the radio (not just sleeping it), which would obviously throw off the current measurement. Definitely something to be aware of.

brolly759

This is so frustrating, you know that?

So I reseated my cables to make sure I am getting the best connection. Now my current is the last configuration is:

sleep current oState: ~105nA
sleep current cState: ~457nA

@NeverDie my 2 AA battery setup right now are @ 3.452v

NeverDie

I recommend you don't use a coincell while testing. Use a big enough battery so that you won't be getting flakey results.

Low Power: How much current? [Solved]

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