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Learn step-by-step how to choose, wire and mount a cooling fan on your Raspberry Pi with local South African tips, parts guidance and troubleshooting.
Match fan voltage, current and airflow to your Pi model and enclosure.
Use 5V/GND or a MOSFET switch for software control; avoid GPIO powering.
Check Communica branch stock, VAT invoicing and accessory compatibility locally.
A small cooling fan helps control CPU temperature on Raspberry Pi models used for sustained workloads (media centres, AI experiments, server tasks, or overclocking). This guide covers fan types, electrical requirements, mounting options, and practical considerations for makers, students and technicians in South Africa.
| Specification | Small 25 mm Fan | Standard 40 mm Fan |
|---|---|---|
| Voltage | 5 V | 5 V |
| Typical current | 60-100 mA | 80-200 mA |
| Airflow (approx.) | 3-6 CFM (50-170 L/min) | 6-18 CFM (170-510 L/min) |
| Noise | Low | Moderate |
Local availability note: Communica stocks a range of fans and Pi accessories across Samrand, Pretoria and Cape Town branches. Check stock and branch collection info for faster turnaround; see the branches and trading hours for details here.
When wiring a fan to a Raspberry Pi, most makers use the 5V and GND pins on the 40-pin GPIO header. Avoid drawing large currents from GPIO signal pins. Use a transistor or MOSFET for switching fans with software control, and add a diode if using motors that can generate back-EMF.
Use Ohm's law and power formulas to estimate load. Example formulas:
V = I * R (Ohm's law) - for resistive loads. Power: P = V * I.
If a 40 mm fan is 5 V and draws 120 mA: P = 5 V * 0.12 A = 0.6 W. For a Raspberry Pi powered from a 5 V, 3 A supply, this adds a small fraction of the available current but always account for USB peripherals and HATs.
GPIO 40-pin header view (top-down) Pin 2: 5V -------------------+ (Red) Fan + Pin 6: GND -------------------+ (Black) Fan - For software-controlled switching: use a GPIO pin -> resistor -> base/gate of NPN/MOSFET -> fan negative -> GND. Include a flyback diode for inductive loads.
For a components list and compatible accessories, explore Communica's collections of fans, power supplies and Raspberry Pi accessories on the site here and the broader product index here.
Affix a heatsink to the CPU with thermal tape or paste, then mount a small fan above the heatsink using screws, clips or a purpose-made HAT. Many Pi cases include mounting posts for 25-40 mm fans; where they don't, a 3D-printed bracket is a common maker solution.
Fan HATs simplify wiring: they plug onto the 40-pin header and often include a thermal sensor and automatic control. When using a HAT, confirm pin alignment and that the HAT supports your Pi model. Browse compatible HATs and brands on the site here.
Control fans with simple Python scripts reading CPU temperature from /sys/class/thermal/thermal_zone0/temp and toggling a GPIO pin through RPi.GPIO or gpiozero. Example pseudocode:
read temp -> if temp > 60°C: set GPIO HIGH (fan on) -> elif temp < 50°C: set GPIO LOW (fan off)
Use hysteresis (a gap between on/off thresholds) to avoid rapid switching. Note: temperatures and thresholds are illustrative; adjust based on your workload and enclosure ventilation.
| Build | Components | Estimate (ZAR) |
|---|---|---|
| Basic fan install | 5V 25 mm fan, jumper wires | ~R40-R120 |
| Controlled fan (software) | 40 mm fan, N-MOSFET, resistor, diode | ~R80-R250 |
Estimates are indicative and depend on brand and supplier; actual prices at Communica will vary. For a full browse of compatible parts and brands, visit the collections index here.
Communica supplies semiconductors and electronic components to industries such as automotive, electrical, automation, mining, and education.
Disclaimer: This content is for educational purposes only. Product availability, pricing, and specifications are subject to change. Always verify current details on the retailer's website before making a purchase. We may earn affiliate commissions from qualifying purchases.
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