Using the BBC micro:bit is fun and simple but, as you can see, it’s an open board with all the electrical parts on display. It’s been specifically designed this way but this does mean there’s a small risk that the parts can be damaged and even overheat. However a little bit of care and caution will ensure you and your micro:bit will stay fit and healthy.
When building circuits they can end up looking a bit like a plate of spaghetti. Un-insulated connections may cause short circuits which at best prevent the circuit from working and at worst may damage the components or the micro:bit.
Purchase insulated crocodile clips. From my experience, children are not sufficiently careful when using crocodile clips to prevent them touching each other.
To save money I recommend buying cheap, generic components from suppliers like Maplins, Radio Spares and Farnell.
Connecting an LED:
An LED has to be connected the right way round in a circuit or it will not light. To help with this the lengths of the two 'legs' of the LED are unequal. The longer leg is the positive side of the LED.
The wires you use to connect components do not need to be soldered onto the component. Soldering is not safe for young children to carry out, without very close supervision, so I recommend twisting the wires together. The pictures below show how wires can be attached to an LED.
Note the inclusion of a resistor on the long leg of the LED to limit the current. This is to prevent the resister from being overloaded and damaged.
The insulating tape is to prevent the two legs of the LED from touching and causing a short circuit
Conventionally, red wire is used for the positive side of the circuit and black for negative.
The supplier of your components can advise on the correct rating for the resistor. Follow the link below to learn more about picking resistors for LEDs.
Connections can be made with 4 mm 'banana' plugs, 4 mm spring connectors or crocodile clips. The picture below shows and LED connected to pin 2 with the positive side being connected to the pin and the negative side to GND.
Watch the video on using pins to add electronic devices (buzzer and LED).
There are a number of different ways that components can be connected to the micro:bit. Some are more successful than others. It certainly helps to add about 20 cm of thin, insulated, multi strand wire to each leg of the component.
Make sure to insulate any bare metal. The best way to do this is with short lengths of heat shrink wrap.
Many components have wires that are weakly soldered to the component and with use these will break off. A blob of glue (I use a glue gun) will prevent this. The small brass tabs on electric motors are particularly prone to this and should be wrapped with inoculating tape or strengthened with glue.
When connecting to the pins, here are some things to watch:
Never connect the 3v pin directly to GND pin, this would be like shorting the terminals of a battery and is not a safe thing to do.
4 mm banana plugs are a good way to connect components. Find ones with stacking plugs as it is often necessary to make two or more connections to the same pin on the micro:bit (as shown on the right).
4 mm plugs, usually grip half way along the plug shaft so don't push them all of the way through - only push them half way for a tighter connection.
When attaching crocodile clips to the 5 larger pins they have a tendency to slide along the edge connector strip if attached as shown in the lower bottom picture. Make sure that your connection does not cross two or more pins (unless you intend to do this). Push one of the jaws through the 4 mm hole at right angles to the micro:bit as shown in the top picture..
Use insulated crocodile clips as shown in the bottom picture. If the crocodile clips are not insulated and they are very close together, wrap them in some plastic tape to prevent short circuits.
If you can afford them, it is a good idea to buy components with 4 mm terminals so that leads can be easily attached and removed. Some schools will have components, like the one illustrated, that are used for circuit experiments in science. Borrow these as they should work (motors and filament lamps excluded) on the 3 volt supply from the micro:bit.
It is possible to purchase components with a length of wire and 4 mm plugs already connected to them. These are more expensive but certainly more convenient.
N.B. The green plugs indicate that polarity is not important.
Spring connectors are a quick and simple way of connecting wires to 4 mm terminals (see picture and video below).
Note that to connect the limiting resistor to the LED, the wires have simply been twisted together.
If time and expertise is available, I would always recommend soldering a 15 cm length of multi strand wire onto components,using red for positive and black for negative where polarity is important to help the children to connect their components the correct way round.. Use a neutral colour, yellow, green blue etc. where polarity is not important. This not an activity for primary school children but you may have a parent who is handy with a soldering iron and would be willing to solder up the components for your lessons and to apply heat shrink to insulate them.
Post a request in your school's newsletter (mine were all done for me by a willing electrician parent who was delighted to help out).
Use the link below to access advice from the pxt.microbit website on using Bluetooth with the microbit.
Smartphone apps and the micro:bit
In the eyes of my pupils, connecting with smartphone apps via Bluetooth is one of the coolest things that you can do with a micro:bit.
For more information, advice, apps and tutorials, visit Martin Woolley's bitty software website via the link below.
The XinaBox components are fully compatible with the micro:bit and represent an excellent resource for extending the micro:bit to create an enormous range of electronics projects. They'm can be programmed using MakeCode and MicroPyton.
The OLED display provides the micro:bit project developer with a much more powerful and versatile graphical interface that overcomes some of the limitations of the 5 x 5 LED array.
See the MakeCode script below to program a pixel in the centre of the display screen to flash blue.
Data display - a simple temperature and light meter.
This was assembled and programmed by a ten year old. The only little difficulty was working out the x and y coordinates to display the labels - Data, Temp: and Light: and the data - in the right places. Trial, error and perseverance got her there in the end.
The micro:bit is connected to the XinaBox, xChip components using a BM02 micro:bit bridge module.
In this example, the light level is being sensed by the micro:bit and the temperature is being sensed by an XinaBox SW01 advanced weather sensor module.
The data is displayed via the XinaBox OD01 OLED Display 128x64 (SSD1306) module.
N.B. No soldering or screwdriver required. The xChip modules click together as simply as Lego bricks, note the small cream coloured XC10 bus connectors used to link the modules.