Selection of an ESP module with ultra low power for non-frequent connections

[vicvicvardt]

Hi all,

I have an IOT application that requires sending data from sensors each hour. It will be powered with 3V lithium-ion batteries.
Since it will transfer data each hour, it will remain 99% of the time at idle.

The application will be installed in a large warehouse (100mts x 100mts) and multiple access points will provide coverage.

Can you help me select the best ESP chip for this application that essentially requires ultra low idle current (deep-sleep?)

Thanks

[ESP_Sprite]

It depends on the application, specifically what you mean by 'idle'. If 'idle' is 'powered down entirely but wakes up again each hour', then any ESP32 can do that. If it means 'collecting some sensor data, not needing much CPU power or memory, and waking up every hour to send that', you want an ESP32 with an ULP; the original ESP32, the S2, S3 and if I remember correctly the C6 have that. (Although you probably want to skip the ULP in the original ESP32 as the later ones are RiscV and as such easier to program.) If 'idle' means collecting data that needs lots of CPU/memory, you'd likely want something that is power-friendly while running; the C6 would be good for that. Generally, these are all rules of thumb and you should check the details of the chip to see if they match your application, one tool to do that would be our product selector.

[vicvicvardt]

Thanks @ESP_Sprite for the elaborated response.

I was referring to Idle as 'powered down entirely but wakes up again each hour'

I'll selected between the S2 and S3 families.

Any S2 or S3 that has an integrated RTC module? I cannot find the filter for this option at the product selector.

[ESP_Sprite]

Both chips have an internal RTC that keeps the time in sleep modes. But do note that 1. the RTC tends to be imprecise in deep sleep mode (max 5% deviation iirc) unless you add an external 32KHz crystal to the chip/module, and 2. there's no provision for a backup battery so if you need to keep the time even when there is no power you're likely better off with an external RTC.