I would prefer 10 days without recharge.
That is 240 hours. One number to go! There is no point in continuing this thread until you have measured and told us the average current draw in mA.
That makes the servo consume some power all the time, to maintain the position. The controller consumes power all the time as well.
Measure the current consumption of the build. Then multiply the current by 10 days and 24 hours to find out the number of mAh needed in the powering battery.
Well, if you use FET an power the servos only when needed and pit the arduino to sleep and replace/remove the LDO ...
If the servos ran continuously, I guess your system would consume about 2.8W
For 10 days you will need about 672 Wh of energy.
If you used a 12V battery with a 5V buck, you would need a a 62Ah battery, not small
A car battery
It's reliable, cost-effective and rechargable.
that's like $100 to $150, that's expensive! and big!
I can suggest traction batteries of plenty of AH, weight 1.5 tons if needed....
You can't have your cake and eat it too!
Lead acid are the cheapest per Ah, anything else will be more expensive.
Just to run the Arduino for 10 days would require a 6.6Ah 12V battery
that's true, for example, a li-ion battery that big is $250.
Go to the scrapyard, ask nicely and you can probably leave with some Pb-acid-batteries.
Yes, i will measure it today.
OK, I will try to put up a mosfet for the Servo power.
(Oh, I dont know what LDO means.
Thanks!
I measured it for the arduino, and on average it is 78 ma
- Current with servos disconnected ?
My bathroom light switch does that with motion detection. I set sensitivity and duration.
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And for the servos, at rest it is 33ma(for both) at rest, and while moving it is 230ma(only one is moving at a time.)
But when in rest, it turns on in the slightest movement.
Isn't that what "entering a room" is?
I set the sensitivity. I have it set to a larger movement, like waving an arm or moving my whole body. I can move slowly enough to not trigger it.
This is not PIR - similar to heat detection of a warm body.
Maybe a more detailed description would be good.
OK, so here is what i have decided:
A car battery(12 V 15Ah) : 36$
A buck converter(20 Amps): 5$
However, i have no idea how to charge the battery.
Thanks you all for your suggestions! I learned a lot just reading through through the replies.
A dynamo flywheel attached to a capacitor, spun by an opening door.