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wingnut,
here is another little "improvement" idea.
Since the 40106 can work with a supply voltage down to 3V (the 74HC14 down to 2V)
You can squeeze the battery life to very low voltages.
The LED illumination would vary a lot in the range 3-6V.
So you need a way to control it as the battery voltage drops with time
Use a potentiometer with a knob(easily accessible outside the "BOX" ) to do that.
replace R3=280 ohm with this:
.
here is another little "improvement" idea.
Since the 40106 can work with a supply voltage down to 3V (the 74HC14 down to 2V)
You can squeeze the battery life to very low voltages.
The LED illumination would vary a lot in the range 3-6V.
So you need a way to control it as the battery voltage drops with time
Use a potentiometer with a knob(easily accessible outside the "BOX" ) to do that.
replace R3=280 ohm with this:
.Will implement what you suggest - in about 6 months - since the circuit works so well at conserving the battery.
The AA batteries I am using would have been thrown out of any respectable household long ago, yet it works fine.
I know we could achieve more efficiency by using a smaller cap and a larger resistor than the 1M. To charge up the cap draws current.
I was wondering how accurate this circuit was as a timer. So timing it for 4 cycles, times were 197s, 193s, 191s, 193s.
Well not quite...
The charging energy of the cap is negligible here is why:
Each time you activate circuit consume energy from the battery
to charge the Cap.+light the LED
The simplest thing to compare is the charge(in Coulomb) drown from the battery:
The charge in a fully charged cap is:
Qc=C*V=220u*6=1320uq
The charge the LED current is drawing is:
Qled= i*T=7m*190=1330mq
so, Qled/Qc about 1000 !
As I said before if you want to improve the Battery life use a 2ma efficient LED...
The charging energy of the cap is negligible here is why:
Each time you activate circuit consume energy from the battery
to charge the Cap.+light the LED
The simplest thing to compare is the charge(in Coulomb) drown from the battery:
The charge in a fully charged cap is:
Qc=C*V=220u*6=1320uq
The charge the LED current is drawing is:
Qled= i*T=7m*190=1330mq
so, Qled/Qc about 1000 !
As I said before if you want to improve the Battery life use a 2ma efficient LED...
My supplier has 2mA LED's but their luminosity is 3.2mcd as opposed to the 2000mcd I am using at present.
Here is their website...
http://www.fort777.co.za/index.php?...Path=269_456_532_536_537_970&products_id=5382
I think I would need a torch to see that LED
Dorke - I can visualise every Western household having in their Xmas stocking, your circuit, mass produced, tarted up, and sitting on every toilet cistern, casting its warm beam down on the target area.
I can see the warm glow in spouses hearts at not having to be disturbed by a bathroom light during the night, and general satisfaction all round at nothing else being spread all round.
I can see folks stumbling out of bed to do their nocturnals, and returning undisturbed by the insomniac shock from glaring bathroom floodlights.
I can see battery companies shares falling.
I can see ....... $$$$$ in your bank account.
Or did that bathroom light just wake me up?
I can see the warm glow in spouses hearts at not having to be disturbed by a bathroom light during the night, and general satisfaction all round at nothing else being spread all round.
I can see folks stumbling out of bed to do their nocturnals, and returning undisturbed by the insomniac shock from glaring bathroom floodlights.
I can see battery companies shares falling.
I can see ....... $$$$$ in your bank account.
Or did that bathroom light just wake me up?
Last edited:
I can see an led light over the wash hand basin......
Don't see it in the schematics!!
I just turn the light on.. Or miss!!!
Martin
Don't see it in the schematics!!
I just turn the light on.. Or miss!!!
Martin
