Re: Current consumption of LCD kitchen timer?

On 2025-05-11 12:51, Pamela wrote:

On 17:15  10 May 2025, john larkin said:

On Sat, 10 May 2025 10:56:01 -0500, John S <Sophi.2@invalid.org>
wrote:

On 5/10/2025 9:58 AM, john larkin wrote:

On Sat, 10 May 2025 14:37:40 +0100, Pamela
<pamela.private.mailbox@gmail.com> wrote:

>
>
I'm interested to know the current drawn by a kitchen LCD digital
timer.
>
(1) How much current does the timer draw when counting time?
>
(2) How much current is drawn when the piezo buzzer is sounding?
(Averaging out beeps and silent bits.)
>
My guesses are 2mA and 25mA, respectively. Is that about right?
>
>
I mean a timer similar to this one, running off a 1.5V battery.
https://www.amazon.com/Digital-Kitchen-Timer/dp/B00GOPICNM

>
That suggests a product line: a series of batteries (AA, AAA, 9v)
that measure current wirelessly, or datalog.

>
Hey! I like that idea!

>
A small PCB could have a tiny lithium battery and a uP with an
internal ADC. A diode would make a logarithmic current-to-voltage
converter from picoamps to milliamps. May as well report temperature
too.
>
Someone could sketch a schematic to discuss. It needs the right uP
and some code. And some mechanical design.
>
Might not handle high peak currents, amps.
>
Of course the electronics could be in a box with a tiny flex running
to the dummy battery. Or just squeeze the flex between the battery
and a contact. Or just sell the flex, with banana plugs on the other
end to go into a DVM. That's too easy.

 I asked the question about current consumption because, when the time
is up, I leave my kitchen timer beeping until it cuts out. That's
usually a minute of beeping.
 If this is done a couple of times a day, would the AAA battery run out
in an appreciably shorter time?
 

I admire your patience.  That would drive me nuts.  I doubt that the beeper requires much current--piezo sounders are pretty efficient at turning battery power into annoying noises. ;)
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
http://hobbs-eo.com