#Raspberry pi fan control mod#
#Raspberry pi fan control update#
#Raspberry pi fan control manual#
#Raspberry pi fan control software#

Most micro-controller or SBC already have a decent circuit to generate PWM signal, you donвЂ™t need special circuit to generate it. According to OhmвЂ™s Law: $V=IR$, the resistor should be 660О© or larger to protect your fan. The white paper says the maximum current is 5mA. The pull-up resistor that I use is 1kО© 1/4W. Warning! The Pi has 3.3V GPIO, so your pull-up resistor must be connect to 3.3V ONLY! You will fry your Pi if Vcc is connected to 5V. The fanвЂ™s RPM signal is an OC(Open-Collector) circuit design (in most fan), so youвЂ™ll need a pull-up resistor to measure output waveform according to Noctua PWM white paper. If your fan doesnвЂ™t support PWM control, then you can see #138 Variable Speed Cooling Fan for Raspberry Pi using PWM and PID controller or PWM Regulated Fan Based on CPU Temperature for Raspberry Pi to use a BJT transistor to use PWM control. I use Noctua NF-A4 5V PWM, a 40mm, 5V PWM fan. In most case pi didnвЂ™t need that amount of cooling performance, so we can use PWM (Pulse Width Modulation) to control fan speed and reduce the noise. Malolo apparently assisted Haz1 to design these.A lot of people uses fan to cool down their Raspberry Pi 4, but the fanвЂ™s noise is quiet problem (in a quiet room). Of course an ATtiny85 programmed via the Arduino IDE (with a bit of assembler to set the timer to 25kHz) would reduce the resistor count вЂ“ needing only the decoupling cap, the filter cap and the pot, and the pot could be replaced with a couple of SMD tact switches to make a really low-profile speed control вЂ“ the chip comes in a 4 x 4mm version.ДЇor fan choice, the quiet Noctura 40 x 40 x 10mm 5V pwm typeВ would be favourite, although there are plenty of other, cheaper, 5V 40 x 40mm and 30 x 30mm fans to try.ДЇor the Malolo case that I printed, there are now some alternative tops that takeВ 30 or 40mm fans.

#Raspberry pi fan control mod#

BTW, MOD pin input current is miniscule вЂ“ even nanisculeвЂ¦. This is actually 200kО©, needing a 330kО© in parallel to get the resulting resistance correct-ish (the values in the diagram are for 250k). To get 25kHz requires 125kО© on the PWM chip SET pin.ДЇor the sake of the thought experiment, I picked one of those little 10 x 10mm Vishay 63M-T607 pots with a knob on topВ from RSвЂ™ website. Regarding the fanвЂ™s PWM needs, Noctura has an application note that describes the required signals вЂ“ 25kHz (21-28kHz) at, loosely, TTL levels.ДЄ note on fans here: as far as I can find out, three-pin fans tend to have power in and a tachometer output, to which four-pin fans add a PWM control input. The parallel resistor pair sets the internal oscillatorвЂ™s base frequency, the potentiometer sets the internal frequency divider (to 16 in this case вЂ“ the voltage on the DIV pin is read by a 4bit ADC and its output value selects one of eight fixed division ratios. The LTC6992-1 version offers 0-100% control, and just needs three resistors, a pot and a decoupling cap to do the job, and maybe an RC filter on the output to roll the edges off for the good of the rf environment. LTC designed them вЂ“ take a look at the data sheet, it is a marvellous little chip, available n a 3 x 3mmВ 6pin TSOT-23.

#Raspberry pi fan control update#

When thinking a diy version, the LTC6992 sprang to mind вЂ“ a 6pin PWM chip that is part of a range of timer chips that offered a vast update on the 555 theme. Called the NC-FC1, but it is not tiny вЂ“ it is 21 x 25 x 48mm, possibly including knob вЂ“ quite respectable as it includes a connector at each end, but a wired-in one would be smaller.

Noctura, maker of quiet fans, also makes a fan controller for the 4 pin types.

#Raspberry pi fan control manual#

While pondering, I wondered what it would take to make a little manual control.

#Raspberry pi fan control software#

0V and 5V are available in the Raspberry Pi GPIO nearby вЂ“ and some companies have come up with kits to add a processor fan taking power from here вЂ“ Pimoroni of Sheffield is a prime example, with its very neat Fan Shim, which has associated software should you want the Pi to on-off servo its own temperature.