Re: Pi PICO W on batteries

From	John R Walliker <jrwalliker@gmail.com>
Newsgroups	comp.sys.raspberry-pi
Subject	Re: Pi PICO W on batteries
Date	2026-06-25 09:21 +0100
Organization	A noiseless patient Spider
Message-ID	<111ioe2$3iarj$1@dont-email.me> (permalink)
References	(3 earlier) <sm0se6c8n2s.fsf@lakka.kapsi.fi> <97F*HqVJA@news.chiark.greenend.org.uk> <na2976Fn4t9U2@mid.individual.net> <111gtqv$348m3$3@dont-email.me> <111i7m9$3g155$1@dont-email.me>

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On 25/06/2026 04:35, wmartin wrote:
> On 6/24/26 08:41, The Natural Philosopher wrote:
>> On 24/06/2026 15:51, Peter Heitzer wrote:
>>> Theo <theom+news@chiark.greenend.org.uk> wrote:
>>>> Anssi Saari <anssi.saari@usenet.mail.kapsi.fi> wrote:
>>>>> The Natural Philosopher <tnp@invalid.invalid> writes:
>>>>>
>>>>>> On 15/06/2026 19:49, Brian Gregory wrote:
>>>>>>> nano timer ??
>>>>>>> What's that then?
>>>>>>
>>>>>> TPL5100
>>>>>>
>>>>>> https://www.ti.com/product/TPL5110
>>>>>
>>>>> I kinda thought modern microcontrollers have this sort of thing built
>>>>> in? Oh, looks like the Pico (no W) draws 2 mA in "deep sleep" and this
>>>>> timer draws 35 nA.
>>>>
>>>> That does sound surprisingly bad for the Pico.  Seems that the 
>>>> RP2040 is
>>>> 0.18mA in 'dormant' (ie deep sleep) and 0.38mA in 'sleep', which is 
>>>> a bit
>>>> better.  So must be something else on the Pico that's not so good in 
>>>> sleep
>>>> mode.
>>> I think (ultra) low power was not a primary design goal for the Pico.
>>>
>>
>> I think that is very true. What attracted me was the amount of flash, 
>> and ram, the availability of wireless and ADCs and the price. Less 
>> than a pint of beer in a nightclub.
>> Arduinos were 3 times the price
>>
>> The ZeroW running debian is a damn sight easier to code for, however.
>>
> Be careful about trusting that ADC, it is somewhat notorious for 
> inconsistent lower bits...summing and averaging helps, if you have the 
> inter-sample time to do that.
> 
The errors are very predictable as they are caused by certain
very low value capacitors in the switched capacitor adc having
incorrect values.  It seems that the chip design tools did not
model stray or fringing capacitances accurately enough.
There is software around that can post process the adc readings
to make a substantial improvement.
https://github.com/kitanokitsune/rp2040adc_correction
John

Thread

Pi PICO W on batteries The Natural Philosopher <tnp@invalid.invalid> - 2026-06-14 12:17 +0100
  Re: Pi PICO W on batteries rbowman <bowman@montana.com> - 2026-06-14 17:48 +0000
    Re: Pi PICO W on batteries The Natural Philosopher <tnp@invalid.invalid> - 2026-06-15 12:31 +0100
      Re: Pi PICO W on batteries John R Walliker <jrwalliker@gmail.com> - 2026-06-15 13:04 +0100
        Re: Pi PICO W on batteries The Natural Philosopher <tnp@invalid.invalid> - 2026-06-15 13:17 +0100
      Re: Pi PICO W on batteries "Peter Heitzer" <peter.heitzer@rz.uni-regensburg.de> - 2026-06-15 12:06 +0000
        Re: Pi PICO W on batteries The Natural Philosopher <tnp@invalid.invalid> - 2026-06-15 13:19 +0100
          Re: Pi PICO W on batteries "Peter Heitzer" <peter.heitzer@rz.uni-regensburg.de> - 2026-06-15 13:58 +0000
            Re: Pi PICO W on batteries The Natural Philosopher <tnp@invalid.invalid> - 2026-06-15 16:52 +0100
    Re: Pi PICO W on batteries mm0fmf <none@invalid.com> - 2026-06-15 12:52 +0100
  Re: Pi PICO W on batteries Brian Gregory <void-invalid-dead-dontuse@email.invalid> - 2026-06-15 19:49 +0100
    Re: Pi PICO W on batteries The Natural Philosopher <tnp@invalid.invalid> - 2026-06-15 20:28 +0100
      Re: Pi PICO W on batteries Theo <theom+news@chiark.greenend.org.uk> - 2026-06-15 20:54 +0100
        Re: Pi PICO W on batteries The Natural Philosopher <tnp@invalid.invalid> - 2026-06-16 01:59 +0100
      Re: Pi PICO W on batteries Anssi Saari <anssi.saari@usenet.mail.kapsi.fi> - 2026-06-24 09:33 +0300
        Re: Pi PICO W on batteries The Natural Philosopher <tnp@invalid.invalid> - 2026-06-24 09:58 +0100
        Re: Pi PICO W on batteries Theo <theom+news@chiark.greenend.org.uk> - 2026-06-24 13:41 +0100
          Re: Pi PICO W on batteries The Natural Philosopher <tnp@invalid.invalid> - 2026-06-24 13:53 +0100
          Re: Pi PICO W on batteries "Peter Heitzer" <peter.heitzer@rz.uni-regensburg.de> - 2026-06-24 14:51 +0000
            Re: Pi PICO W on batteries The Natural Philosopher <tnp@invalid.invalid> - 2026-06-24 16:41 +0100
              Re: Pi PICO W on batteries wmartin <wwm@wwmartin.net> - 2026-06-24 20:35 -0700
                Re: Pi PICO W on batteries John R Walliker <jrwalliker@gmail.com> - 2026-06-25 09:21 +0100
                Re: Pi PICO W on batteries The Natural Philosopher <tnp@invalid.invalid> - 2026-06-25 10:12 +0100

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