Re: Current consumption of LCD kitchen timer?

Paul <nospam@needed.invalid> wrote:

On Sun, 5/11/2025 4:57 PM, john larkin wrote:

On Sun, 11 May 2025 16:32:03 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
 

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

 
Whoever invented the piezo buzzer should be welded into a prison cell,
with a dozen piezo buzzers.
 

 
Does a piezo run off 1.5V ?
 
This sounds like alien technology.
 
 

Some do. But the kitchen timers I’ve seen have small auto transformer
(tapped inductor about size of quarter watt resistor) to make the buzzer
much louder.

--
piglet