3 x 120mm Arduino controlled RGB LED fan holder

prusaprinters

A colleague had some spare 120mm RGB LED pc fans lying around and he asked me if i could create a holder for them to be used as a ventilator. He wanted to be able to control the fan speed and the LED color as well.  What began as a quick 1 afternoon job - well - it took a bit longer in the end… 🙈 So i made this 3 x 120mm Arduino controlled RGB LED fan holder with RGB LED effects and fan speed control. In this version it is solved with 3 buttons to control the fans, RGB LED colours and LED brightness. In future versions of the software it might be possible to add a web interface to be able to set all these values more dynamically.  Functions:With the 3 buttons you can cycle through the following values:Fan speed: 100%, 75%, 50%, 25% and 10%LED brightness: 100%, 75%, 50%, 25% and 0%LED color modes: 8 including 2 rainbow colour modes. See video below.With the power switch on the back of the base you can turn the fan and LEDs on/off.The code will work with the named 4-pin PWM fans and the 3-pin 5V RGB LEDs in them. Other fans with other connectors might not work. I have not tested other fans. Video:Music credit: Used some free music from Apple iMovie Needed parts:3x 120mm 4-pin PWM 12V fan with 3-pin 5V RGB controllable LEDs1x ESP8266 (D1 Mini)3x push button Ø16mm1x barrel jack for power input Ø12mm1x power supply 12V/2A with barrel jack1x DC-DC voltage step down board (12V —> 5V)1x On/Off-Switch 6x M4 x 40mm screw6x M4 nut 12x M4 washer4x Wood screw (3mm x 20mm)Some wires in different colors Some hints for mounting the printed parts and electronics:Begin with cutting off the connectors from the end of the cables of the fans. I cut them in an angle to remember which wire was on which side of the connector.Push both cables of each fan through the little hole in the “middle” part and try to route the cables to the “middle” part edges as close as possible without knots.Put 6 of the washers and the 6 screws and slide them into the holes of the “front” part. Slide the screws through the fan holes and the “middle” part and tight the fan cables in the “middle” part again to have a good routing of them from the front. Mount the “post” part to the “back lid” part with the 3 bigger printed screws.Slide each fan cable though the hole in the “back lid” and “post” part. If needed add a little angle to each beginning of the cables. Route the cables to the bottom of the “post” part and tight them again to avoid knots and too short cable ends in the “base” part later.Slide the “back lid” part with the “post” part over the “middle” part and secure it in place with the other 6 washers and the 6 nuts. Take care of the orientation of the logo on the “front” part.Route the fan cables through the hole of the “base” part and screw the “base” part to the “post” part to fix it in place with the 4 wood screws. 3mm holes are prepared in both parts.Now to the “base” part and the electronics:Screw the “barrel jack” in place. Measure the contacts with a voltmeter after adding the power supply connection to find out which pin is for the GND (black) and 12V (red) output. Solder a red (+ contact) and black (- contact) wire to it.Stick one of the red wires through the hole of the “power switch” and solder it to one of the “switch” contacts. Solder another red wire to the other contact of the “switch”.Press the “switch” into its hole in the “base” and make sure not to squeeze the wires.Solder the black and the open red wire from the “switch” to the input +/- contacts of the “DC-DC step down board”. Add another 2 wires (red/black) to the same contacts which will be needed later to power the fans with 12V as well.Take the voltmeter again and attach it to the output of the “DC-DC step down board”. Attach the “12V power supply”, turn on the “switch” in the base and set the output voltage of the DC-DC step down board to ~5V (i set it to 5.15V) with a small screwdriver and the small screw on the blue potentiometer of the DC-DC step down board. Turn off the power and disconnect the power supply after the output voltage is set to around 5V.Add 2 red and 3 black wires to the output +/- contacts of the “DC-DC step down board”.One pair of red/black wires need to be connected to the “ESP” to the 5V/G pin.The other red/black pair of wires are used later to power the 5V LEDs of the fans.Screw now the “3 push buttons” in the “base” part.The 1 remaining black wire of the 5V output is connected to one contact of the 3 “push buttons”.From the same “push button” contact add another black wire to be connected to the “2nd push button” and from there to the “3rd push button” one black wire more.The other sides of the “3 push buttons” are supposed to be connected to D1/D2/D3 of the “ESP” as listed in the table below with the named wire colours (grey/cyan/yellow).From the “ESP” solder 3 wires (green/blue/orange) to D5/D6/D7 and connect them to the “fan” and “fan LED” wires as listed in the table and the schematic below.Solder the red/black 12V and 5V wires to the “fan” and “fan LED” power wires.Check the wiring again and this step will almost complete the installation.Wrap some electrical tape or better use heat shrinks around the DC-DC board, all wire connections and the ESP to avoid unwanted contacts between the parts. I also used a little super glue to glue the DC-DC board to the inner walls of the base part away from the other parts. Take care to be later able to reach the Micro-USB port of the ESP to be able to upload new code to it (in future).Upload the “code” now to the “ESP” if not already done before.Use the 4 little printed screws to close the base with the base lid.Use a little super glue to attach the 3 round “button” named parts to hide the original stickers on the fans as shown in the pictures.With this you should have completed the build of this little project.  Wiring: Connecting the parts is as easy as possible. Some soldering work is required.You will need to set the DC-DC step down board to have the 12V for the fan motors as well as the 5V output by meassuring the output voltage for the ESP8266 and the LEDs.The ”tach” or “rpm” wire (blue color) should be connected to D6 of the ESP, although it is not used by the code. I saw some strange fan behaviours when it was not connected. Showing the rpms would be possible too, but I did not see a useful usage for this information and removed the code for this information for now.Please check the table which pins are connected for the project as well as the pictures:ESP8266:3x fan 3-pin:3x fan 4-pin:DC-DC:BarrelJack:Switch/Button:Color:D5D    green5V5V OUT +   redGGND OUT - 3x button X pin 2black  +12VIN ++12V+12V to +12Vred  GNDIN -GND blackD6 RPM   blueD7 PWM   orangeD1    Button 1 pin 1greyD2    Button 2 pin 1cyanD3    Button 3 pin 1yellowCode: The code can be found on my GitHub repository. Printing instructions:Supports needed for the “front” and “base” part from the printbed only0.3 draft profile used Textured sheet usedHappy printing :)