Current consumption of LCD kitchen timer?

Imagine some line cook who has a dozen orders in his head, all overlapping, some well done and some medium rare.

Do you design electronics? That benefits from quantitative instincts, and I think helps develop them.

But people are very different, and there's always Spice.

LT Spice, not the other sorts of "spice".

Same here. My solution is to have a timer in count-up mode running next to the stove, so I can glance at it as needed. I still get distracted, but the effect is reduced.

Joe

I am fairly poor at timing because I tend to use the cooking time to do something else, then get engrossed in that and forget what the time is. Luckily I do have a good sense of smell, so sometimes I can catch things before they are too badly incinerated.

If I am cooking several batches like a production line, I tend to fill in the time by washing up the utensils and cleaning down the surfaces ready for the next batch, so I am right beside the cooker and don't forget.

You are the exact opposite of my wife, who's signature phrase is:

"Good heavens! It can't be that time."

How about a few of those birthday cards which play a 'tune' when opened

- for special occasions?

I once had a gf who was always between 1 hour and 2 hours late. I've never had a watch but I'm basically never late.

My wife tends to put things on a burner or into an oven and go away. I like her, so I keep an eye on things when I can.

I tend to design control systems by fiddling in Spice, instead of using hard stuff like control theory. I can usually guess R and C values pretty close, and iterate from there. Bad guesses can fail to converge, the "lost in space" effect.

LED contrast is *very* sensitive to battery voltage - the chip is already using an antiphase pair of signals and possibly a voltage doubler to drive the LCDs. 3.3v to 5v being a typical drive voltage.

At such tiny currents the battery has essentially its shelf life and will supply 10-20uA almost forever but at gradually lower voltages. Once the voltage is below a certain point the clock still runs but you can only see the display by holding it at just the right angle.

One big annoyance with such LCD displays is that they really won't accept rechargeable cells because the fully charged voltage is too low to run the display with an acceptable contrast.

I think it doesn't make a difference.

And it is not that trivial to measure, because cmos circuitry only draws current at the instant of switching. So, use a scope. Otherwise, I would try to measure it.

The piezo sounder will be at least 1mA current draw and might be 5-10mA. That is about 100-1000x the standby current for a digital clock chip with a bare metal LCD display.

At 1mA a 2400mAh battery lasts 2400 hours = 100 days At 10uA the same battery lasts 240000 hours = 10000 days ~ 22 years (which vastly exceeds the battery shelf life self discharge time)

So yes it does shorten battery life each time it beeps for a whole minute but probably not by enough to even notice unless you set a 1s delay and keep on resetting it so as to draw 1mA for the sounder. (almost continuously).

Even if the sounder takes 10mA a 2400mAh battery could run it for 10 days continuously (long enough to drive you bonkers).

Great! How you gonna fit it inside the timer compartment?

Nah. Bridge type drive using two port pins doubles the voltage. I've done it and it's been in a project in my house for about 5 years. Just checked and it still works. I check it every year. I drive it at its resonant frequency so that it makes max noise.

On some domestic appliances I have the designer has included thne option to turn off the beeps :)

The option should be to turn them on.

How about the non-optional flashing mode that all LED torches seem to have? Design sponsored by the manufacturers of migraine drugs?

If your car is dead on the side of a road, they can be used as a warning that will last longer than a flare.

Still, a closet light doesn't need to blink.

I get migraine auras but don't get the headache, which can be horrible for some people for days.

Yesterday the upper half of my visual field want dark, with a sort of burning tree in the corner. That's a new one. Couldn't read for about

Does that include the ball-peen hammer option?

Agreed, but the design is such that you have to click through all the possible modes, in order to switch the torch off. I wouldn't mind if flashing was a separate selectable mode, but the usual arrangement just puts lots of extra wear on the ON/OFF switch - which is always the weakest component in the whole thing.>

I have the same from time to time (aura but no headache). It sometimes makes reading difficult, but doesn't usually last more than a few minutes. Fortunetely I've never had the problem whilst driving.>

Never had a burning tree. It's probably best to avoid googling for that.

I somtimes wonder if engineers have any tendencies towards autism or auras or face blindness or any of those sorts of things.

Dyslexia could explain all those bad manuals. And posts here.

In my torch, I can press lightly, not fully down, and it is enough to disconnect the battery and change to the next mode.

Yeah, I would prefer a second switch to change modes. And I'm not affected by blinking lights, I just need to switch the torch at full power fast.