This table shows various data about each of the pins on the micro:bit edge connector. is a fantastic resource for further information on the micro:bit pins and how they are used by some popular accessories Pins and Signals Pin 9 is no longer jointly shared with the LED display, but Pin 8 and Pin 9 can be configured for NFC (though this is disabled by default). The diagrams below show the assignation of the micro:bit pins. The back rings are connected to the front rings, but the back small strips are unconnected. Only the pins on the front are connected to signals. There are a number of external PCB connectors for purchase with an 80w 1.27mm pitch that can be used to easily access these extra pins. The smaller strips spaced at 1.27mm on the edge connector have additional signals, some of which are used by the micro:bit, and others that are free for you to use. 3 of these rings are for general purpose input and output (GPIO) and are also capable of analog, PWM and touch sensing, and two are connected to the micro:bit power supply. There are 25 strips/pins including 5 rings for using with 4mm banana plugs or crocodile clips. To maintain positive pressure, you need to have a higher combined CFM for the intake fans than the exhaust fans.The edge connector on the micro:bit is used to connect to external circuits and components. When adding fans to a system, maintaining positive pressure within the case can prevent dust from being sucked into any open holes or crevices. Some manufacturers incorporate LED lighting into their fans as well.

Larger fans can usually spin at lower speeds and still move plenty of air without making much noise. Some fans even come with built-in LED lights, others are more performance focused such as this Noctua Chromax fan. Thiago Trevisan/IDGįans vary in size, speed, blade shape and color. This information will be on the package or on the product’s information page. Look for one with a high air flow (measured in cubic feet per minute, or CFM) and low noise level (measured in decibels, or dBA). Fans with a diameter of 120mm are typical in newer cases. The most common fan sizes fall in the 70mm to 140mm range, but fans as large as 230mm are becoming more popular.

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