esp32 with ULP and RTC using AA batteries for a year

eramax
Posts: 2
Joined: Sun Dec 24, 2017 3:41 pm

esp32 with ULP and RTC using AA batteries for a year

Postby eramax » Sun Dec 24, 2017 4:00 pm

hello,

* I am looking to design a project will work with 4*AA for a year or more
* The project has four buttons to get feeds from users and store these feeds in a counter for each button using the ULP and RTC memory using interrupt IO so the ulp will only wake up when i click on the button and the ulp will check which button had been clicked and increase its counter variable and then return to sleep again.
* Always the main cpu is in deep sleep mode because i don't want to loos any power As possible.
* The RTC will daily be used to wake up the main cpu and wifi to send the collected data (collected by the ulp) once a day.

assume I will use AA alkaline batteries typically have a capacity rating of over 2,500 mAh

My questions:
* does this idea is good or it is better and can be done with esp32 or it is better to use another mcu with esp8266 ?
* can you calculate estimated working days for this solution i think the ulp will esp32 with ulp will be in deep sleep mode always but the ulp will be active when users click (assume 1000 click per day ) and the esp will send these data once a day using wifi network
* can i use a ready boards like nodemcu or wemose or so or it will take a lot of power in deep sleep mode and so i have to use the esp32 with a Breakout Board?
* can i use microPython or it is better to use arduino ?
* can the ulp make a buzz when i click on a button or light a led ?

Regards

eramax
Posts: 2
Joined: Sun Dec 24, 2017 3:41 pm

Re: esp32 with ULP and RTC using AA batteries for a year

Postby eramax » Thu Jan 18, 2018 10:30 pm

any help please

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kolban
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Location: Texas, USA

Re: esp32 with ULP and RTC using AA batteries for a year

Postby kolban » Fri May 25, 2018 5:45 pm

At the highest level, my thinking is:

1 year = 8760 hours
4AA at 2500mAh per battery is 10000mAh

This means we need an average of 10000/8760 = 1.14mA consumption per hour (or less).

My loose understanding is that when the ESP32 is in deep sleep mode, it is ticking along at the microAmp level which is less than 1mAh. When you power on radio, there is a dramatic jump in current consumption but you will only need that for short periods.

To truly answer your question, you will need to build out an ESP32 and put it in deep sleep mode and measure how much current it is consuming. From there we can start working out maximal costs for other services... what is the maximum duration you can power up the ESP32 to full power plus radio etc.
Free book on ESP32 available here: https://leanpub.com/kolban-ESP32
Available for ESP32 consulting.

Deouss
Posts: 244
Joined: Tue Mar 20, 2018 11:36 am

Re: esp32 with ULP and RTC using AA batteries for a year

Postby Deouss » Fri May 25, 2018 7:39 pm

I used to work on similar project involving agricultural data. You could buy this:
https://www.aliexpress.com/item/New-TTGO-ESP32-WiFi-Bluetooth-18650-Battery-holder-seat-Module-2A-fuse-4-MB-SPI-Flash/32854080565.html
Image
and connect it to 2W-5W solar panel charging lipo battery during day. It works great even now. It just measures weight and temperature and sends data over wifi.

WiFive
Posts: 1852
Joined: Tue Dec 01, 2015 7:35 am

Re: esp32 with ULP and RTC using AA batteries for a year

Postby WiFive » Sat May 26, 2018 1:52 am

kolban wrote:4AA at 2500mAh per battery is 10000mAh

At 1.5v, so half of that at 3v.

WiFive
Posts: 1852
Joined: Tue Dec 01, 2015 7:35 am

Re: esp32 with ULP and RTC using AA batteries for a year

Postby WiFive » Sat May 26, 2018 1:55 am

With the default configuration (20ms ULP wakeup period), average current consumption in deep sleep mode is 16uA.


https://github.com/espressif/esp-idf/tr ... system/ulp

If it wakes up only once per day for 10 sec it should use <500mah per year

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