Good low power strategy when operation is "closed" overnight

Notecard API
1

Hi All,

I’ve got several use cases where the facility is closed in the evening. I’m solar powered so I want to reduce power consumption as much as possible during the closed nighttime interval.
Should I put the system in minimum mode at night at “closing time” and then back to periodic when the facility reopens in the morning? I know the notecard has features to minimize power even in periodic mode, so if put my main MCU to sleep during the night, will I essentially be in low power mode already since I wont be making any card requests. I’m noob to blues wireless, so any suggestions would be helpful. Thanks

2

Hi @micromet,

Sounds like an interesting project!

I would steer clear of minimum or off, unless it’s absolutely necessary. Those two options create space for your Notecard to become permanently disconnected.

I think your instincts are good:

I know the notecard has features to minimize power even in periodic mode, so if put my main MCU to sleep during the night, will I essentially be in low power mode already since I wont be making any card requests.

You are correct. If you use card.attn to put your host MCU to sleep for 8-12 hours (whatever) via the EN pin, then wake up in the morning and start all over again.

In most periodic configurations, you’ll find that within a minute or so, the Notecard will idle at 8-9uA. If it’s sitting still, then it will only consume energy for scheduled inbound syncs, driven by the hub.set:inbound parameter.

As long as your setup routine (executed when the MCU boots) configures inbound to your desired value, then before you call card.attn, you can set inbound to a distant value like (60 * 24). Then it will be reset to the appropriate value when the MCU wakes.

Here’s a guide from the dev site that should be useful:

2 Likes
3

Hi, I am also interested in this one.
I have an ESP32-S3 and need to make just one measurement every day at 3:30h AM. What would be the best strategy for low power operation so that Notecard can wakeup host MCU?

Regards,

1 Like
4

I have the same interest for ESP32-S3 project of my.

Regards
Rob Oudendijk

5

I would connect the enable pin (EN) of the ESP32-S3 to the attention pin (ATTN) of the Notecard.

You can follow the pattern laid out in this example:

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6

We’ve been using a solar powered solution with an ESP32-S3 for tank level monitoring. We wake up every hour and take a reading, transmit it, and go back to sleep. The Notecard is in minimum mode and we haven’t had issues.

As mentioned above, Notecard ATTN line is connected to an ESP32-S3 input programmed to wake up the ESp32-S3.

In this thread Low-power "mode":"minimum" example? I included some of our code to demonstrate how it works.

Karl

1 Like
7

Hi Karl, thanks for the code you posted over on the Low-power “mode”:“minimum” example?.

I tried to implement that strategy but I’m having trouble with handling the DFU when using minimum mode.

Any chance you share a more complete set of code of your monitoring example to help us newbies ?

Thanks,

Jay