Circuitry Basics

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Micro:Bit

The BBC Micro:Bit will be the brains for all of our projects. It's easy to use, robust, and has a great visual editor interface as you saw in the Coding Basics video. Since we don't want to permanently affix our micro:bit to any of our projects (But you can if you really like it!) we'll be using the Pin:Bit Breakout Shield so that there's no need to permanently attach anything to the microbit itself.

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Pin:Bit Breakout Shield

The Micro:Bit plugs into the slot on the Pin:Bit and allows us to plug the micro:bit into a breadboard or plug other wires onto the pins instead of soldering or just wrapping the wires on. Make sure to plug the micro:bit all the way into the slot, it's a tight fit!

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LEDs

LED stands for "Light Emitting Diode" and is essentially just a power efficient light bulb. These LEDs typically operate on 1.8V-3.6V and around 20mA. Usually LEDs are used in conjuction with a resistor to limit the current passing through the LED. This is because running the LED for long periods at voltages or current higher than it is rated for could cause it to burn out or have a shorter life span. For the purposes of these projects, we won't be using resistors since we won't be making our LEDs flash ON for more than a second or two at a time which shouldn't have a significant impact on its overall lifespan. If you plan to make something that requires an LED to be lit continuously, it would be a good idea to consider adding resistors to your circuit, although we won't dive into that here. The "Diode" part of LED means that the light will only light up and allow electricity to pass in one direction. The LED has to pins or "legs" coming off the bottom. The longer leg is Positive and the shorter leg is Negative. If the legs have been cut, you can still figure out which is which by finding a flat spot in the plastic on the base of the LED, this flat spot is on the Negative side.

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Transistors

Transistors are complicated and can be used in very advanced ways, but for our purposes we'll be using it as a simple ON/OFF switch. When power is applied to the middle pin, it allows current to flow from the right to left pins, so the switch is "ON." When no power is applied to the middle pin, it doesn't allow current to flow from the left to right pin, so the switch is "OFF." This component allows us to use the microbit to turn a separate circuit on and off!

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Jumper Cable

These cables are used to connect different circuits on the breadboard. They could also be used to solder to in a pinch. Red is typically used for Posisitve and Black for negative, but there's really no difference between the wires other than color. As long as you remember which color does what you can use whatever color you like.

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Dupont Male to Female Jumper Cable

These cables have a pin on one and and a hole for a pin on the other. If you happen to be male or female, you can probably imagine why this cable is named that. Although it usually comes in a "ribbon" where all the wires are fused together, you can pull these wires apart to use them individually or in smaller groups. Just like the jumper cables, the only difference between the wires is the color, so you can use whichever ones you like. In our projects, we typically use these cables to solder other wires to so that they can easily be connected/disconnected to the pins on the micro:bit breakout shield. That way you never need to solder directly to your micro:bit, although you absolutely can if you want to!

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Groovy Noodle

The Groovy Noodle wires are similar to a regular spool of wire, but they have some key advantages. The wire insulation is made of soft silicone, which allows you to be able to "strip" the insulation off the wire using only your finger nails, no additional tools required! The soft silicone insulation is also soft against your skin, perfect for wearables, and is heat resistant which is perfect for soldering novices. Normal plastic insulted wires will start to melt if you hold the soldering iron near it for too long. The wire strands beneath the insulation are also very receptive to solder, which makes them even easier to use in soldering projects.

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Breadboard

Unfortunately it's not made of bread, but the Breadboard is what we'll be using to prototype our circuits on. In this diagram I've connected w few wires to the board and you can see which holes are connected to that wire by the green circle. There are two long columns on each side the run the length of the board, and each column is connected all the way down the board. This is useful for when you want to just have a power or ground rail that runs the length of the board that is easy to connect any other components to. Other than these four columns that run the length of the board, the rest of the holes in the middle are only connected to the 5 holes in the same row. For eample, the wire connected to the second row at the top will connect to anything in the other 4 green holes beside it. Same thing for the wire connected to row 5. There is a divider in the middle, so if you want all ten holes on the same row to be connected, you'll need to use a jumper to connect them across the middle divider.

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