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MI:power board for the BBC micro:bit

The MI:power board for the BBC micro:bit is a stylish way to power your BBC micro:bit from a 3V coin cell. A piezo buzzer is built in and a battery is included.

Availability: In Stock.

Code1+ 10+ 100+
(£4.98 incl VAT)
(£4.56 incl VAT)
(£4.32 incl VAT)

The MI:power board for the BBC micro:bit brings real portability to your wearable projects. The stylish, lightweight PCB is designed to fit snugly against the BBC micro:bit and features a built in buzzer and 3V coin cell holder.

When assembled, the MI:power board is connected directly to the 3V, GND and P0 connections on the micro:bit. The 3V and GND connections provide power to the micro:bit and the built in buzzer is connected to P0, which is the default output pin when using the audio functions in the Block Editor software.

The board has an easy to access on/off switch, which makes it easy to turn a project on and off, rather than have to disconnect the power supply from the BBC micro:bit.

Once the unit is assembled and attached to the BBC micro:bit the mechanical fixings prevent the battery from being removed unless you use a screwdriver, so whatever the use, the battery will remain safely in place.

Spacers, fixings and a battery are all provided.

Please Note: BBC micro:bit is NOT included.


  • Power your BBC micro:bit from a stylish PCB.
  • On-Board buzzer.
  • Easy access on/off switch.



Project Ideas Video:


Free Laser Cutter DXF Files:

We've also created some free downloadable resources for you to use with your laser cutter. Included in the downloads are DXF files for designs that fit directly to the Mi:power board that allow you to attach it to your belt, wrist strap, lanyard, stand it on your desk or on a design that can be placed in your garden or a plant pot. You can see some examples of these in the images below.



  • Length: 51mm.
  • Width: 42mm.
  • Height: 6mm.





Use The BBC micro:bit As An Instrument Tuner
Use The BBC micro:bit As An Instrument Tuner
In this tutorial we are going to highlight how easy it is to code the BBC micro:bit as an instrument tuner. We will focus mainly on making a Guitar tuner but we will also provide download links for several different types of tuner.
Project Ideas For The MI:power Add On For The BBC micro:bit Including Free Laser Cutter Files
To highlight the range of possibilities that using the MI:power board to power your micro:bit opens up, we've created some free laser cutter files that you can download and use with your own laser cutter. All of the designs fit directly to the MI:power board and increase both the portability and the potential uses for your micro:bit.
Options for Powering the BBC micro:bit
This Kitronik University Resource is a part of the BBC micro:bit partnership and explains the various options available for powering your BBC micro:bit.


Posted by Holger Schlingloff, Thursday, 9 February 2017 on product MI:power board for the BBC micro:bit


One should be careful when using the MI:power board NOT to plug the Micro:Bit into a USB port at the computer. Even with the switch set to "off", the KL26Z USB chip on board will start to overheat, and, eventually, overheat, causing permanent damage to the Micro:Bit. I experienced this behaviour with two Micro:Bits, so it is repeatable.


  • Posted by Michael Lockhart on Thursday, 9 February 2017

    Hi Holger, With regards to the issue you are experiencing I can confirm that having the MI:power board attached won’t be the cause of this. There is a diode both on the MI:power board and on the micro:bit which ensure that power is only drawn from one source at a time. It will draw power from which ever source has the highest voltage. As such the issues you are experiencing are related to the micro:bit units themselves and it is possible you have received a damage unit(s). As such it would be best to contact the supplier you received these from, if it was ourselves please contact

Posted by John, Tuesday, 20 December 2016 on product MI:power board for the BBC micro:bit


Hi, how can I test that its working? Currently I am just unplugging the USB and just flicking the on switch, but nothing happens. I think the battery may be dead... what steps can I take to solve this? Note: I just got it, so it hasn't been used and I don't know if its faulty.


  • Posted by Michael Lockhart on Tuesday, 20 December 2016

    Hi John, the easiest way to test this is to upload some simple code that turns P0 on and get this to output a frequency between 200Hz to 10kHz, this should then make the buzzer sound. You also need to ensure the battery is correctly inserted and that the screws are making contact with the micro:bit.

Posted by Mr Day, Wednesday, 28 September 2016 on product MI:power board for the BBC micro:bit


The tab on the on / off switch is easily broken. Where would I get a replacement switch from?


  • Posted by Michael Lockhart on Wednesday, 28 September 2016

    Hello, I’m very surprised to hear the switch on the board is easily broken. As the tab is small it should be difficult to snap off by hand. As the switch is a small surface mount component it isn’t possible to get a replacement, it would need a replacement complete board.

Posted by E Vine, Wednesday, 7 September 2016 on product MI:power board for the BBC micro:bit


How much is carriage to CM23 5HX for 20 : of MI:power board for the BBC micro:bit?


  • Posted by Michael Lockhart on Wednesday, 7 September 2016

    Hello, 20 of the MI:power boards would put the order over the £40 value to get free delivery, there are also options for a faster shipping option. To view these if you put the items you wish to purchase in the basket and use the ‘estimate shipping and VAT’ to obtain all the shipping costs. To view all the terms for delivery please see

Posted by Graham Bonham, Tuesday, 23 August 2016 on product MI:power board for the BBC micro:bit


Is it likely to break anything/cause overheating if the battery power is not switched off before the micro:bit, powered by this power board, is plugged into a USB lead connected to a computer (so that the micro:bit is connected to two power sources at once: the coin cell and the computer (through the USB lead))? My gut reaction is that it would be a really bad idea to have two sources of power connected at once but I don't have the requisite knowledge to be able to judge and it could well turn out that I'm wrong.


  • Posted by Michael Lockhart on Tuesday, 23 August 2016

    Hi Graham, it shouldn’t break anything if the power is left turn on with the MI:power board and it is plugged into the USB port, it would be similar to if the battery cage was left plugged in when it was plugged into the PC. However it is recommended that only one device is used to power the micro:bit at any one time.

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