hello guys,
i am think of building a mini quadcopter using a Pro Micro, but it will be fed by a 3.7V 150mAh mp3 battery, so is it possible to give it that voltage ?!
and would the L293D work fine with that voltage ?
here is the datasheet in the attachment files which i bought from the shop here in my region
Yes. Apply power to the Vcc input, not to Raw. Below about 3.5 V, operation at 16 MHz is not guaranteed. See the ATmega data sheet for details.
ok so simply apply voltage to it from battery to VCC and make my circuit, and about the L293D would it work fine with that voltage ?
firashelou:
About the L293D would it work fine with that voltage ?
No.
Absolutely useless.
It is specified as only 4.5 to 36V but it is an extremely poor and outdated design for any low voltage work, should never really be used below 12V. It uses bipolar Darlington totem-pole outputs; Darlingtons are particularly inefficient.
Incidentally, exactly the same thing applies to the ULN2003/2008.
Paul__B:
No.Absolutely useless.
It is specified as only 4.5 to 36V but it is an extremely poor and outdated design for any low voltage work, should never really be used below 12V. It uses bipolar Darlington totem-pole outputs; Darlingtons are particularly inefficient.
Incidentally, exactly the same thing applies to the ULN2003/2008.
ok then what should i do to drive 4 small motors from a micro IR heli ?
firashelou:
ok then what should I do to drive 4 small motors from a micro IR heli ?
Thought you would ask that. 
Do you need to reverse them?
If not, you need only one transistor per motor or even better, a suitable "logic level" FET that will conduct adequately at 3.5V.
In fact, my understanding is that the "micro" helis use miniature "coreless" motors which cannot be reversed anyway.
Paul__B:
Thought you would ask that.Do you need to reverse them?
If not, you need only one transistor per motor or even better, a suitable "logic level" FET that will conduct adequately at 3.5V.
In fact, my understanding is that the "micro" helis use miniature "coreless" motors which cannot be reversed anyway.
lol ! that was my mistake, in fact no i don't need to reverse them 
i just need to control them by potentiometer via infrared signal
and about charging from the controller how can i do that ?
firashelou:
and about charging from the controller how can i do that ?
That would be a wholly different topic! 
Paul__B:
That would be a wholly different topic!
yes you're right but key worlds for google search would be helpful because i tried some but didn't went the way i wanted it to 
Yes, you need a dedicated lithium polymer charge controller for that.
Paul__B:
Yes, you need a dedicated lithium polymer charge controller for that.
well, i got an idea and would like to know if it will work, the heli i have is working good except the support of the blades is broken, so i was thinking about taking the circuit, cut the motors wires and take the motors away, then take the circuit and use it as a charger between the souce and the battery except that i will not have a battery full detector, so what do you think ?
Not so sure on the details there, I am afraid.
Paul__B:
Not so sure on the details there, I am afraid.
it is similar to this one, but with 1 LED
http://cdn3.volusion.com/zvafp.xgbdv/v/vspfiles/photos/UJ4805M-18-2.jpg?1338968999
