Nano + 4X4 keypad + 16x2 LCD + ZBee2 = Power Effishent

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mikerufty
 
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Nano + 4X4 keypad + 16x2 LCD + ZBee2 = Power Effishent

Post by mikerufty »

I have a "almost" working prototype that is a 4x4 matrix keypad connected to a Nano. It's input is stored and sent to the LCD display connected over i2C. Then sends the data needed over an XBee series 2 in API mode.
What I would like to do it make it extremely power friendly as in run at least a month or more on a 3.7 LiPo pack. Then input cycle will only happen every 1 to 2 hours and everything can sleep during that time. To accomplish this I know I would need to replace the hardware with a 3.3v MCU and display.
In your opinion would it be best to just use a chip and build my own Arduino with no USB and using a non-liner regulator? Or just use a 3.3 Mini Pro and replace the liner regulator with a buck switching one. I would have the Arduino sleep and only wake when a key is pressed. I am thinking using 1 of the 4x4 pins as interrupt connected. Say when "D" is presses the interrupt is disconnected, sets a timer to say a wake a few seconds for the rest of the input, then reattaches the interrupt and sleeps. The XBee can sleep and use a pin to wake so the Arduino can wake it before sending the serial data.
So my big dilemma is really "What is the best low quiescent current" way to step down the 3.7 LiPo cell (or equivalent) so when all is sleeping that it is not constantly draining too much.
PS, I am very new to this.

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adafruit_support_mike
 
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Re: Nano + 4X4 keypad + 16x2 LCD + ZBee2 = Power Effishent

Post by adafruit_support_mike »

The first thing you need to do is measure the amount of current your circuit uses while it's active. Next, figure out how much time it will spend active over a month. That will give you an absolute minimum for energy consumption.

Do that and decide whether it's even possible to run the circuit for that long using the kind of battery you want.

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