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Topic: Attiny 85 with 3V CR2032 Coin Cell Battery (Read 974 times) previous topic - next topic

Vincent19

Dear all,

Recently I am planning to use attiny 85 powered by a CR2032 coin cell battery to light up some LEDs randomly. I tried to connect them but it seems that the LEDs is actually not that bright.

Any problems/solutions ?


spycatcher2k

use a smaller resistor - or a step up converter to 5V
Drew.
http://www.uk-pcb.co.uk - My UK Based PCB Fab & Assembly Company
Design work undertaken
SMD & Thru-Hole assembly

Vincent19


knut_ny

you may even do with a coupe of germanium diodes and capacitors.. Use two outputs to make AC
see
http://en.wikipedia.org/wiki/Charge_pump
Ny

fungus

#4
Feb 09, 2014, 06:45 pm Last Edit: Feb 09, 2014, 06:54 pm by fungus Reason: 1

Recently I am planning to use attiny 85 powered by a CR2032 coin cell battery to light up some LEDs randomly. I tried to connect them but it seems that the LEDs is actually not that bright.


A CR2032 has very limited current capability, maybe only 4mA.

a) You won't need a resistor with the LED when you're on battery power.

b) You'll need to reduce the current used by the Tiny85, this makes more available for the LED.

Disable all the parts of the chip that you aren't using, especially the analogue parts.  Functions for doing this are here: http://www.nongnu.org/avr-libc/user-manual/group__avr__power.html

See the section on "power management" in the datasheet for more info (also the "Supply Current of I/O modules" section, under "22. Typical Characteristics").
No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

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