Soft-e-Safe RPi0 Power Switch

Soft-e-Safe RPi0 Power Switch protects your Raspberry Pi Zero files from the corruption that can occur during power loss.

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Soft-e-Safe gives your Raspberry Pi Zero a smart power switch that makes sure it gets a graceful shutdown - even if the power fails. A graceful shutdown protects the files on your SD card from the corruption that can occur from a sudden power loss. It combines a battery, electronics and software to detect when the power fails, switch your RPi0 to battery power, and perform a safe shutdown. In addition to a safe shutdown on power loss, Soft-e-Safe lets you safely turn your Raspberry Pi Zero on or off.

I was inspired by the comment Lady Ada gave at about 19 minutes into the 2/2/2016 #DeskOfLadyada video. Pi-Zero-Contest-Adafruit-Video-2 That was when she said this.

"With great Linux comes great file system inconsistency risk. So, you do have to shutdown cleanly."

- Lady Ada

I thought to myself, "How am I going to make sure I get a clean shutdown of my Raspberry Pi Zero if the power goes out unexpectedly?"

I decided to browse through the Adafruit store to see what goodness I could hack together to protect my SD card files from corruption due to power loss. I was not disappointed. I found a few items that I could put together to protect my files.

  • Prototyping

    ESharpAxe02/25/2016 at 08:00 0 comments

    Started prototyping with a Raspberry Pi 2 and a 5V Trinket with a 74LVC245 level shifter. I needed the level shifter while I wait for my 3V Trinket to arrive.

  • State Diagram

    ESharpAxe02/25/2016 at 05:46 0 comments

    I added a snap shot of the state diagram that walks through the start up and shutdown of the system.

    Here's a short video that steps through the logic.

  • Cats are lost

    ESharpAxe02/24/2016 at 05:17 0 comments

    I've tried explaining this to my cats, but their still a bit lost on the signaling between the Trinket, the Raspberry Pi Zero, and the PowerBoost.

    I plan to draw out a state diagram that shows the how the pieces interact over time.

  • Now with Trinket

    ESharpAxe02/24/2016 at 03:14 0 comments

    Remove Power Switch

    After looking at more details on the Adafruit PowerBoost 500 Charger, I noticed the breakout for the ENable pin. Looks like I don't need the FET power switch after all. The PowerBoost can handle the power switching. Yay!

    Add Trinket

    I've remove the power switch and added an Adafruit Trinket - 3.3V. That will give the project the smarts it needs.

    Bigger LiPo

    I increased the size of the LiPo battery from 150 mAh to 500 mAh.

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Erland Lewin wrote 02/19/2016 at 22:08 point

I've been designing a Raspberry Pi power switch for controlled startup and shutdown for my PiChart project ( See these blog posts: and  

I don't have an integrated LiPo or boost converted, but we could discuss the rest of the circuit if you're interested! 

I've built it on a breadboard, and I'm planning to order a PCB with more optimized components.

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