Putting Note into sleep mode


I’ve got a Note on a carrier A. I’m measuring the current input via the micro-USB connector and it appears to be sinking 15-60+mA.

How do I put the Node into deep sleep and what current consumption should I expect. i.e. How near can we get to the spec’d 6uA?



Hi @ajlennon,

You’re not going to reach such low current when using the micro-USB port. You’ll have to use one of the other power ports (V+ or BAT) to get down to the specified power draw.


OK - is there anything else I have to do?

If you haven’t seen it yet, I would highly recommend you read through our Low Power Design guide!

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Thanks - I’ll see what it comes down to using V+ and the sleep command then…

This is what I am seeing atm

It depends on what phase of activity the Notecard is in. For example, what you’re showing could be when the cellular modem is powering on and/or communicating with Notehub. You’ll need to wait at least 30 secs or so after you power it on.

You can also try a temporary {"req":"hub.set", "mode":"off"} request (see docs) to examine the draw without any sync requests interfering.

That’s about four-five minutes worth from turning it on.

Sorry, I didn’t realize that was a video, thought it was just an image.

I’d be curious what happens when you try the hub.set request.

I will give it a go Rob!

A solid 15mA with the modem off @RobLauer

OK I am impressed. I did a third test where I put the power in through GND and V+ on the header.

Modem is still off. It’s a pretty steady 15uA which will do for me :slight_smile:

I note that notecard-cli comms are still possible and when I do serial-over-i2c the consumption raises to 2mA then eventually drops back down to 15uA.

Very nice indeed.

I think I just need to have some more clarity now on modem configuration and assuring myself that I am in control of when it starts sinking lots of mA and for how long.

Nice outcome :slight_smile:

Time passes…

So I put the note into “minimum” mode and it seems to be going around and around trying to make a connection, which I guess explains the high consumption

Not sure why it’s failing or how long it’ll keep on trying (hopefully not forever!)

Tried reading “card.wireless” to look at the CSQ but it’s not returning the count or net objects…

Time passes…

Still seems to be trying to connect so a couple of things

  • this is slightly worrying as I can see the battery being exhausted. What options do we have to control this behaviour?

  • it seemed to work ok when it had the whip antenna provided with the Pi carrier. Now I have it connected to the onboard antenna on the “A”

Could probably do with working out how to view the wifi - not sure why card.wireless doesn’t return it…

Time passes…

And now after 9+ hours it seems to have dropped back to 20uA although I don’t think it managed to get anthing through over cellular… ???

Time passes…


root@e6994032274d:/usr/src/app# notecard -interface i2c -req ‘{“req”:“hub.sync.status”}’ --verbose
{“alert”:true,“status”:“modem: insufficient battery current available for power-on (358 min remaining in safety delay) {modem-power-failure}{network}{extended-network-failure}”,“sync”:true}

Which Notecarrier-A model are you using (is it the AL or the AA)? What type of battery are you using as well? Might also be good to know your cell signal strength (e.g. bars from card.wireless response).

Hey @RobLauer - apologies for the delay. The forum said I was too keen and stopped me posting for a bit :smiley:

Here’s a video run through I did. It’s a NoteCarrier-A

Now I need to understand why powering the V+ pin from my huge power brick is resulting in the Note telling me there’s not enough power to power the modem.

I would love the signal strength but as I showed above the note isn’t returning that information to a card.wireless request…

That video is fantastic by the way!

Can you point me to the spot where you perform the card.wireless request? I must have missed it.

Glad you like it! You can see it’s going to be a pretty powerful technique for edge processing on low power IoT devices.

When you put it together with the fast booting bare metal work I have been doing it’s going to be pretty neat…

On the CSQ - Ah I noted it up above but didn’t include captures - I’ll grab something.

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Hi Rob,

Apologies for the delay. The modem is now returning CSQ. I suspect the problem was because it was limiting due to it thinking the power was too low. I will keep on working and post next time it happens!



I think I have figured out where I am going wrong.

I added my bench multimeter inline with the power to V+ on the Note Carrier A and it appears that as the Note is initiating it’s comms. the bench PSU is causing it to reset (perhaps because of a brownout).

When I take out the monitoring then I get a connection!

Of course then I can’t monitor power consumption :slight_smile: Need to have a little think!

Hi @ajlennon!

Super awesome project!

I’m not sure of the burden voltage on your bench multimeter, but I have been using the CurrentRanger which is designed to effectively eliminate burden voltage when testing current consumption on low power devices.

I’ve been using it successfully with the Notecard. It has reasonably high accuracy and converts current to voltage 1:1. It’s very reasonably priced for what it is.

Hopefully that helps,

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Hey Zak,

Thanks for the kind words. Yes it is a fun project isn’t it :slight_smile: Seems to be going quite well.

So one of the interns in the office had a go at putting a CurrentRanger or similar together a few years ago and never made anything of it. Looks good to me! I’ve taken your advice and got a pre-built one on order as I am always needing some decent logging on IoT sensors I am putting together that can handle both deep sleep through to radio on…

As I was googling I also saw this which references the JouleScope which looks interesting too