Learning with Raspberry PI, Delivery VIII – Manufacture of SAI online to dev boards

In the previous article of this series We learned to monitor temperature, and we also saw three distinct forms of refrigerate our Raspberry PI.

Today thanks to Juan Antonio Valverde, and Manuel of ComponentesOnline We will learn to make a UPS online to shield our devices before any blackout or power failure.

Any operating system, available for Raspberry PI they are susceptible to fail at any time, and if not turn them off properly probably will end up corrupting the SD card, or causing any electronic fault.

In addition to make regular backups, It is advisable to have an uninterrupted power supply system that it may prevent in the event of power failure to avoid losing the last days work or money invested in materials.

The SAI conventional are designed for desktops which consume much more than a Development Board, and that is why they tend to be expensive and many users opt to make their own SAI Home.


On the other hand are reaching the market specific solutions designed for Raspberry PI, but at the moment as well as faces are hard to get; and only allow its use to a single Raspberry.

P1020110_aI have chosen to consult with qualified professionals, and collaboratively have developed a SAI for this type of plates with a capacity to hold between three and six Raspberry PI for more than half an hour, expandable limits by replacing the battery with one that offers more mAh.


5V output for up to 6 simultaneous devices.

The electronic part of the SAI It has been designed by Juan Antonio Valverde, with components that Manuel of ComponentesOnline has given us, In addition to providing their experience giving a second opinion regarding the development of the same, We have also relied on specific revisions to the final design of Jordi Binefa.

To make our SAI you will only need a power supply and a battery LiPo both with an output voltage of 12V, a voltage converter of 12V to 5V, a couple of diodes rectifiers BY255 3A 1300V, and one Breadboard.

The SAI scheme, developed by Juan Antonio Valverde.

We'll begin by connecting the pole positive of the power supply to one of the tracks of the Breadboard, to channel the tension in the desired direction by a diode because thanks to the avoid battery to send power back into the power supply.

OLYMPUS DIGITAL CAMERANow connect the second diode to channel from the source voltage and the battery to the inverter of voltage that will feed our Raspberry, It is very important to place the diodes in the position as in images; then connect the positive pole between the two battery diodes, and all the GND in a same track of our series Breadboard, I have chosen the of one side already what are precisely designed for this purpose.

OLYMPUS DIGITAL CAMERAThen connect the output of the diode coming from the positive pole the battery to the positive voltage regulator, and the GND in the two previous series.

OLYMPUS DIGITAL CAMERAWe will finally stop charging the battery a few minutes and check the correct functioning of the SAI, cut from power supply as in the video below.

In future installments, we will improve our SAI so I acted only in case of failure of the main power supply, i.e., transform it into a UPS offline.

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11 thoughts on"Learning with Raspberry PI, Delivery VIII – Manufacture of SAI online to dev boards

  1. Hi John,

    It will depend on the distance that you place the input voltage, with 12-24V, you make sure that in 100 meters greater than 5V is the tension that comes from end to end, to finish regulating it to 5V at the end point.

    If you put batteries 7, 5V will work perfectly, but you can put the UPS less metres from your PI Raspberry; just be sure that the voltage regulator to support it, the tutorial is compatible.

    Thanks for your comment 🙂

  2. Hi I have a question
    the diagram indicates battery LiPo type my question is if there is any reason Specifies to use this type of battery and if you can use a cell phone battery

  3. Hello Yikoruoru,

    The chosen battery is lithium polymer (LiPo) because they are normally used for robotics, and/or development such as Raspberry PI plates.

    With a mobile phone battery you could do a proof of concept, even that would not be the battery most suitable and relatively little last ups.

  4. I've been thinking and I would like to know who has this different system to: buy a battery 5000mah for phones xiaomi. We connect the raspberry to the battery and turn the battery always plugged in. battery li-po with 5v output. I think it is much more simple than all this but want to know if he has any against in this regard.

    • Hello p1n0, Thank you very much for raising doubts.

      The disadvantages are many, Since using it would eventually break very fast since the battery is not prepared to hold that kind of intensive applications; that if you can turn on the PI with a mobile of 5V battery since batteries usually give less current of that brand on the label.

      In addition this UPS can put it to 100 metres from the Raspberry without any problems since arriving at the end of the cable while Miss voltage, This always exceeds the 5V at destination.

  5. Good, see that to last the time and not have been able to remove the tutorial of the SAI offline. You know where I can find one, would be very interested. Thank you. Good job.

    • Hello Antonio, Thanks for your comment.

      Juan Antonio, the guy that was going to take care of the development of the electronic part suddenly disappeared for what I have not yet regained this project.

      If someone offered to develop such party, I could charge me for the software; If you fancy them to do this you can contact me through the form of the blog.

      Thank you for your interest in this project.

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