MiniUPS4RPi - A spare power supply for Raspberry Pi project video thumbnail
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€1,346 pledged of €2,900 goal
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By Francisco Dominguez
€1,346 pledged of €2,900 goal
backers

About this project

Genesis

Yes I love Genesis (Tony, Mike and Phil) but I am not here to explain my musical tastes. I am here to talk about my love for Raspberry Pi and the reasons I developed this hat.

I always thought that Raspberry Pi had a big potential for industrial and commercial solutions, but every time I planned a solution that involved a RPi, I always clash with the same issue: SD data corruption. Power fail in a critical write can generate a unusable RPi (problems, problems, telephone calls, more problems, etc). Could we avoid it? Yes, if you spend some time googling you can find some solutions with external batteries. But, no. I don't need a lot of hours of a secondary power supply bigger than Raspberry Pi. I just want a compact solution that allows me to shutdown my Raspberry Pi safely, and to turn it on when energy is recovered.

Proposed solution

The solution is quite simple: a battery charger, a small and compact Po-Li battery and a few electronic components to obtain 5V again, as depicted in the following figure.

Schema of the hat
Schema of the hat

 The small 8-Bit Microchip microcontroller reads the input voltage and comunicates with Raspberry Pi thru serial port.

The capacity of the battery lets the Raspberry Pi to be powered for 5 to 20 minutes, depending on the RPi consumption (CPU usage, peripherials, USB ports in use, etc).

The hat has a switch that works like a reset/on/off button. If the Raspberry Pi is turned off, a short push turns it on. If the RPi is working, a short press sends the order to shutdown the Raspberry Pi. A long press turns it off by cutting the power abruptly.

How does it work?

When the PIC12F1572 reads the input voltage to step up the electronic, it can determine whether the power comes from the external main power supply or from the battery. In addition, if it is working in battery mode, the microcontroller knows the charge of the battery.

MiniUPS4RPi detail
MiniUPS4RPi detail

All this information is sent to the Raspberry Pi through the serial port (GPIO14 and GPIO15).

A program written in Python is reading the serial port. When the voltage is near a critical value, it shuts down the Raspberry Pi safely. The program is under GPL license.

Python code
Python code

Profit and loss

What your Raspberry Pi will gain with this hat?
  • An UPS to protect it from power outages for a few minutes.
  • Avoid data corruption
  • Internal/external power button
What your Raspberry Pi will lose with this hat?
  • Serial port. This feature is needed to be taken to manage the hat
What will you win with this hat?
  • Peace
  • Tranquility
What will you lose with this hat?
  • A few bucks

Timeline

Rewards

The only offered rewards are volumen discounts. You can choose the number of units you'll receive. These rewards have a very special price. 

Take into account that after the campaign the final price of one unit of MiniUPS4RPi after the campaign will be 40.00€/42.00$ + taxes + shipment.

Risks and challenges

The challenge is to create a more compact solution than the presented prototype, and to move some components. For example, the microUSB connector is over the display port. The final PCB will have this connector near GPIOs to avoid this situation.

We have a functional prototype. All design and testing work is done. The main risk would be some delays in fabrication of the product. The deadlines shown are a realistic calculation, but we don't have the control of all of them.

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  1. Reward no longer available

    Pledge €27 or more About $29

    Early bird - One

    You will receive one unit of MiniUPS4RPi fully functional. Just plug and play.

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    • MiniUPS4RPi
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    Pledge €35 or more About $38

    One

    You will receive one unit of MiniUPS4RPi fully functional. Just plug and play.

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    • MiniUPS4RPi
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    Pledge €66 or more About $71

    Two

    You will receive two units of MiniUPS4RPi fully functional. Just plug and play.

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    Pledge €290 or more About $311

    Professional - Ten

    Oriented to shops. You can get 10 units of MiniUPS4RPi at 29.00 € per unit

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    • 10× MiniUPS4RPi
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    Pledge €540 or more About $579

    Professional - Twenty

    Oriented to shops. You can get 20 units of MiniUPS4RPi at 27.00 € per unit

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    • 20× MiniUPS4RPi
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Funding period

- (30 days)