Rheostats Baybus How-To

Disclaimer : I will not be responsible for any damage(s) to your system, yourself or worst still, someone else!! You do it at your own risk!!

So you've just hacked your casing so you can install fans to improve it's airflow and help cool down your overclocked PC. Your system now runs cooler but you're getting a headache from all the noise the fans make!! You wondered whether you can live with all the noise or is there a simple way to control the noise. Enter the Rheostat Baybus!

I'm not sure who pioneered this idea, but Cliff Anderson of Fanbus.Com was the one to build one and make it available to the masses. He has many types of Fanbus and Baybus for sale up on his site and also some very useful FAQs and guides to help fellow DIYer's like me!! So give it a look-see while surfing!!

Back to the guide, the rheostat is basically like a variable resistor, controlling the voltage supply to your fan. By turning the control shaft on the rheostat, you can vary the amount of resistance and thus varying the voltage supply to the fans. Note : I have received some emails telling me that due to the resistance, the rheostats could get pretty hot and could even burn! Yes, that is true, but ONLY if you overload the rheostats by connecting too many fans to it and exceeding the wattage rating of the rheostat. My 5.1W 120mm Sunon fan is hooked up to one of it and the rheostat does feel warm to the touch after about an hour, but NOT HOT!

OK, enough blabbering and let's continue with the guide. For this guide, I will be showing you how to make a 3 Rheostats Baybus with a Master Control Switch. You will need the following;

Start by marking out the position of the rheostats and switch on the faceplates and then cutting them up. This can be done easily with a hand drill and a filing tool. Stop occasionally to check the alignment. You should be able to obtain something like the picture below.


10Watts, 25 Ohms Rheostats & Knobs
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Wire connectors
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12VDC switch
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Faceplate
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In order for the rheostats to control different fans, you will need to make a fanbus for connecting the fan wires. I have posted the Fanbus Guide previously so I'm gonna skip it. But if you missed it the last time round, you can check the Fanbus Guide here. The only difference is that only 3 12V line wires would be utilized for each rheostat. The other one is being reserved for future use.


The Fanbus
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Internal view
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Once the faceplate is done, it is time to solder the wires to the rheostats.

It's a good idea to start by securing your rheostat onto a small clamp or jig. If you don't have one, you can mount them onto the faceplate and use it as support. Get some wires and strip off about 5mm of the protective cover of the wire and solder the wire onto one of the terminals. You will only need to use 2 of the 3 terminals found on the rheostat. You can cut the other one off or just leave it as it is.

After the wires are soldered, you can use a heat shrink tubing for the soldered connection to prevent any short circuit. The tubings also gives it that professional look, or in my case, to hide the crappy soldering job!!!


Use a jig to mount the rheostat
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Connect wire to the terminal
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Both wires soldered to the terminals
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Heat shrink tubing
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Continue to do the same with the rest of the rheostats. I did not solder the wires on the switch as the wire connectors fit perfectly and tightly onto the switch terminals. Once you're done with the soldering, fix on the rheostats and switch onto the faceplate. You should get something like the pics below. The control unit is done.


The Fanbus
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Internal view
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Next is the fanbus. Crimped on the wire connectors onto the wires of the fanbus to connect to the control unit. Make sure you label the wires to prevent confusion when attaching the fanbus to the control unit. As for the power supply, connect a male Molex Connector to the fanbus. This Molex connector will be connected to the PSU for the voltage and ground supply. You might also want to use electrical tape to seal off the connection of the wires to prevent them from short circuit when they accidentally come into contact with one another. Connect the fanbus to the control unit and you're done!!


Fanbus with connectors
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Completed unit
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Now it's time to test your new toy!!

You can hook up the baybus to your PC or an external 12VDC PSU, if you have one. Secure your control unit and start to connect your fans to the fanbus and hook up the Molex connector to the PSU. Once you're ready, fire 'em up!! I used 1 X 120mm 5.1Watts Sunon, 1 X 92mm 2.6Watts Sunon and 1 X 60mm 1.4Watts Sunon for the test. As you can see, each one of the fans wattage is within the rated capacity of the rheostats.


External 12VDC PSU
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Ready for action!!
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In the bottom left picture below, you can see that the PSU is already turned on but not the control unit switch. Thus none of the fan is spinning. All the rheostats are set at the minimum turn. The next picture shows the switch turned on and the 92mm and 60mm fans starts to spin. The 120mm fan failed to start though. Maybe 25 Ohms is a little too much! :O)


All ready here!!
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Time to rumble!!
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The 120mm fan only starts to spin when the control knob is set to almost half way as shown in the bottom left pic. It seems to have a hard time starting at the minimum turn of the rheostats. But once it starts to spin, none of the fans stalled when the rheostats is set back to the minimum turn!! I then cranked the rheostats all the way up just to get the full effect!! Very cool, but noisy!!


Finally it spins!
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None of the fans stalled!
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Full Speed Ahead!!
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The setup seems to work perfectly. You can now attach it to the front bezel of your PC. Looks like it was factory installed! Now you can have some peace and quiet at last!! I hope this has helped you with your own project or at least gives you an idea for your own setup. Here's the schematic diagram of the setup for your reference;


Looks like factory installed!!
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My personal setup!
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Comments? Mail me!