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Bomber67
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KNOT Power consumption - power saving possible?

Mon Oct 17, 2022 1:53 pm

I am developing an application based on the KNOT, using GNSS and NB-IOT data transmission.
It is supposed to stay idle for a period, then send a very small amount of data to a server and revert to "idle".

The BG77 chip contains features for saving power, for instance flight mode and Power Saving Mode vs the WWAN.
But what about the KNOT itself?
Measured the current draw to approx 85mA at 24V, i.e. around 2W, this is without Wifi and BT in use.
Setting the BG77 in flight mode did almost nothing to the power draw. Same with lowering the clock frequency to minimum 550 MHz.

In many ways the Knot seems ideal to this kind of operation, but a continius draw of 2W makes it unsuitable for simultaneous battery powering and portability..
Making use of /system scheduler for performing tasks needs the RB to be up and running all the time.
Another approach would be a separate circiut based on a 555 timer and a micro relay that boots up the KNOT every x minutes, long enough to do its data acquistion and reporting, and then powering it off.
I would rather see a routerboard like the KNOT using very little power, with limited CPU performance and some kind of real "sleep mode", but I guess this does not exist....

Any of you guys that have addressed this problem?
 
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chechito
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Re: KNOT Power consumption - power saving possible?

Mon Oct 17, 2022 5:12 pm

i think maybe you can use an esp32 or arduino with a relay to control when to powerup the KNOT
 
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Re: KNOT Power consumption - power saving possible?

Mon Oct 17, 2022 9:04 pm

I also would use arduino of some kind that acts as a timer and turning on the KNOT. But I'm not sure how much the KNOT likes to be powered down/up all the time.

The only better way is to do your application in an arduino/rpi-zero/esp32 native and connect it to a NB-IoT modem of some kind. For example
https://se.rs-online.com/web/p/communic ... ls/2475630
 
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Re: KNOT Power consumption - power saving possible?

Mon Oct 17, 2022 10:19 pm

Thank you for your tips chechito and mada3k :-)
Of course running the entire application on an Arduino would be an option, but you know I love Mikrotik and RouterOS...strange that Mikrotik haven't paid more attention to power consumption on an IoT device.
I could very well have traded CPU performance for less power consumption.
Introducing a "sleep mode" with timer for RBs would also be a good idea.
 
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Re: KNOT Power consumption - power saving possible?

Tue Oct 18, 2022 1:18 am

Energy saving and IoT are just the opposite.
It is absurd to think of saving energy by using the IoT, as there are even more devices to power than before.

Yuo can't use LoRaWAN for your needs?
 
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Re: KNOT Power consumption - power saving possible?

Tue Oct 18, 2022 4:02 am

...strange that Mikrotik haven't paid more attention to power consumption on an IoT device.

i think KNOT is not a IoT device itself, is a Gateway for other IoT devices, it is expected to be available for the IoT devices to connect to it, in fact you are confirming KNOT has a very low Power usage

i think you are trying to do an unexpected use of KNOT and because of that you are facing this "limitation"
 
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Re: KNOT Power consumption - power saving possible?

Wed Oct 19, 2022 8:43 am

Energy saving and IoT are just the opposite.
It is absurd to think of saving energy by using the IoT, as there are even more devices to power than before.

Yuo can't use LoRaWAN for your needs?
Yes, of course will more added sensors require more power.
But this is not about that, what I'm considering is the power draw and expected battery life of the KNOT for a "portable" application.
 
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Re: KNOT Power consumption - power saving possible?

Wed Oct 19, 2022 8:58 am

...strange that Mikrotik haven't paid more attention to power consumption on an IoT device.

i think KNOT is not a IoT device itself, is a Gateway for other IoT devices, it is expected to be available for the IoT devices to connect to it, in fact you are confirming KNOT has a very low Power usage

i think you are trying to do an unexpected use of KNOT and because of that you are facing this "limitation"
Interesting view, and maybe you are right.
But the fact that it has an IOT communications device (BG77) onboard must mean that MT in some way consider that Cat-M and NB-IOT has some advantages over regular LTE for what the KNOT is meant to achieve.

If power consumption was out of the question, they could might as well have based it on the R11e-LTE6, then it would work OTB on literally every network worldwide with a standard SIM-card with a data plan.

In fact I am not "confirming KNOT has a very low Power usage", what I say is the exact opposite.
IMHO 2W draw is nowhere near what you would expect from a battery operated device (which the KNOT presumeably is not meant to be), if I'm not wrong it is in the range of a whole lot of other MT devices like for instance the hAP ac2.
 
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Re: KNOT Power consumption - power saving possible?

Thu Oct 20, 2022 4:41 am

i found very difficult to get a device like KNOT which is a Fully Functional Router / Gateway with a Power consumption below the 2 Watts you confirmed to us
 
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Re: KNOT Power consumption - power saving possible?

Thu Oct 20, 2022 9:55 am

i found very difficult to get a device like KNOT which is a Fully Functional Router / Gateway with a Power consumption below the 2 Watts you confirmed to us
Exactly.
And that leads me to think that it is primarily intended to be some kind of IOT hub and not an IOT device itself - like you suggest.
But then they could might as well equip it with regular LTE.
An exception could be a case at a very rural spot where power supply is in place, but cell coverage is next to absent.
 
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Re: KNOT Power consumption - power saving possible?

Thu Oct 20, 2022 11:53 am

Usually <0.5W is only possible with sleep/deep-sleep modes, and that usually stops many functions in the operating system, something a router/gateway never can do.

KNOT is not the IoT device, it's just a gateway.

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