3 ms·
What kind of battery drain does reading the accelerometer cost? Seems a little silly.
by gburt 14y ago
What kind of battery drain does reading the accelerometer cost? Seems a little silly.
- objclxt 14y agoVery little to none - accelerometer packages also handle some power management themselves, typically with various 'modes' of accuracy and sleep/awake states. There are a number of embedded devices (my FitBit, for example) based around MEMs accelerometers and tiny batteries with a charge that lasts days, if not weeks. Compared to everything else that's going on (backlight, CPU, WiFi or the cellular modem) it's peanuts.
- deleted 14y ago[deleted]
- deleted 14y ago[deleted]
- dangrossman 14y agoProbably a negligible amount. The accelerometer in HTC phones uses only 200μA when active, and only wakes itself when there is motion. I don't know exactly what part an iPhone uses, but it'll be similar. Compared to the CPU's power usage, which will definitely be running if the screen is on and the app is in use, that's nothing.
- lloeki 14y agoCPU? I bet the biggest sucker of them all is the display.
- gamble 14y agoIt has to be powered up all the time anyway, to detect orientation changes.
- dangrossman 14y agoThe accelerometers in phones have wake-on-motion built-in. They use essentially no power when there is no motion, with a sleep/wake delay of something like 1ms. Even when the accelerometer is powered up, it uses negligible power compared to the CPU/display/radios. The reason you wouldn't want to use the accelerometer all the time in an app is that it keeps the CPU from sleeping, since the CPU has to be awake to read & process the signals from it. Keeping the CPU awake when it could otherwise be sleeping is going to drain battery far more than the accelerometer itself.