Low Power Arduino
July 23, 2020 Business
A common Arduino, for instance the Mini does not consume very much power, typically 40 MA when connected to a USB cable. If you’re going to be powering your Arduino on something other than batteries, the power requirements normally isn’t a concern, it will be just too little to make any difference. Once you start something like a remote monitoring application where you are required to run with battery power, power consumption can become significant. In my working experience hoping to calculate the amount of time an arduino will continue with a battery pack is quite tough due to the fact that there are so many factors involved, first of all there are a lot of types, alkaline, Nickel Metal Hydride, lithium-ion, rechargeable, non-rechargeable. Even for a certain kind of battery say triple A, there will be widely varying storage capacities depending on the style of battery it is ( Nickel Metal Hydride or lithium-ion) and there is likely variability among the different brands (usually you get what you pay for). When your batteries get depleted, the voltage supplied drops, if you are using 4 triple A batteries, which supply six volts to operate an Arduino which requires at least 5V, the Arduino may very well stop working when the voltage supplied dips too low, despite the fact that there is still a substantial quantity of energy remaining in the batteries.
I won’t be doing any specific calculations here for the reason that I find the figures are not practical. I must mention that batteries usually are specified in terms of Milli-ampere hours. So anytime your Arduino is hooked via USB, its functioning at 5 volts, if it is drawing forty Milli-amps, that isn’t the same measure of wattage as requiring forty Milli-amperes from a 9 V battery. Moreover it depends on what your application is. Are you just taking input from some type of analog monitoring device or are you using it on a servo, these have dramatically different power needs, and once more in my experience you’ll find it not useful to calculate. I find the best way is get a hold of some batteries you have around the house and see how long they last, then use those measurements to make empiric calculations.
Assume you’re working on a remote tracking device and you need to have the Arduino to continuously measure something for some significant period of time. I did something similar with a DS18B20 sensor that was on the inside of one of the cold frames in my yard, it would have been a pain pulling an extension cord out to the yard, and not such a good idea to leave it outdoors and exposed, so I deciding on operating on a battery.