I'm new to Raspberry Pi and I had a few questions. I want to connect a raspberry pi to a e-ink display, it will retrieve content over wifi. It will only display when a motion sensor picks up on light in the room (or movement, whatever). By doing this, I hope that it will save a considerable amount of power, and so when powering the whole thing via a battery I'm hoping it will last quite a while (anyone able to estimate how long?). Obviously something will still be requiring power when it is idle, because it needs power to constantly look for motion, does anyone know how much this uses up?

If I put the whole thing in a waterproof casing fit for the raspberry pi will it protect it from humidity from steam that you get when the showers been on for a while in the shower? By casing it up, will it then overheat?

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    Hello and welcome! Please note that the Raspberry Pi is really not good when it comes to low energy consumption and power down modes. Compared to a microcontroller based solution (which should handle this task) it seems really power hungry.
    – Ghanima
    May 12, 2015 at 17:49

1 Answer 1


I am assuming this will be a mobile based device, or one not located near a power outlet, hence the need for the battery pack. One of the biggest current drains will be the WiFi dongle. This will need to be on continuously to be able to receive data, likewise the CPU will need to remain powered. So only processing the small amount of data on demand will not greatly extend the system's run time.

As for your questions regarding cases (waterproof and heating) a quick search of this site will turn up several related questions on this site. However, the short answer is that the Pi may overheat in a high temp/humidity environment - Only by testing can you be sure.

This is a case of a more complete description of your project may help us give you better answers.

  • It's also worth noting that e-ink displays don't draw power (relatively) when they're not actively drawing an image.
    – Jacobm001
    May 12, 2015 at 21:06

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