Currently a draft:
Low power design considerations
I started this writeup after I was doing some reading about low-power arduino setups.
- Previous designs are pretty inefficient - lets take a look at how inefficient, why and what we can do to design a better power system in the future. First we need to take a look at some of the constraints that we're dealing with:
- Rooftop; no place to plug in
- Hypothetical design consideration: raspberry pi - is it possible?
- About 1A / 5V → 5W
- 6W solar panel charger not enough to charge during the day
- 10W solar panel might be enough: https://www.adafruit.com/product/2747
- Cost consideration
- Driving down power consumption means cheaper solar panel and cheaper battery
- The design choices are different for each hardware platform - this is not a critique on the designers / people
- Apple
- Cranberry
- Dragonfruit
- Guava?
- The assumption from before: we needed to either run things at 3.3v or 5v. Turns out we could run things at 2.8v - if we take a look at all of the modules, the one with the highest minimum voltage is the XBee at 2.8v. The atmega328p can technically run at a lower voltage.
- Need to figure out this situation: if we run the mcu at 2.8v, can we still use the regular usb-serial converter? I think the logic lines will be fine.
- XBee power states (sleep mode)
- Microcontroller sleep modes
- Sensors - how much power do they consume?
- How low can we go? (Theoretical)
Footnotes:
Links:
Example main
Using the low power library, here is what the loop function looks like:
sleep_counter++;
LowPower.idle(SLEEP_4S, ADC_OFF, TIMER2_OFF, TIMER1_OFF, TIMER0_OFF,
SPI_OFF, USART0_OFF, TWI_OFF);
if(sleep_counter % 15 == 0){
board.sample(&board);
}
Authors
Contributing authors:
Created by kluong on 2020/04/28 03:18.