Guide AquaXtreme or MCP-600 R.P.M. Signal Mod. Pics!

AquaXtreme or MCP-600 R.P.M. Signal Mod.

Hello people, this is my first mod-guide, hopefully I can make this easy for everybody to understand (English is my second language). First I have to thanks Spiv at www.pc-workshop.net (dead link) for an excellent article on how to get R.P.M. signal from fans without R.P.M cable, after reading this article I study the possibility to use his same principle on water pumps, and the key word was “Hall Sensor”

The Basics:




Basically all brushless motors use hall sensors. The Hall sensors signal magnet position and polarity information to a logic circuit. This mod will convert the out-put signal of 1 of the hall sensors inside the AcuaXtreme pump (or MCP-600, same pump) into R.P.M. signal to the motherboard.

The parts I used:
ULN2803 Darlington array chip (Jameco #34315)

18 pin IC socket (Jameco #112230)

Vertical Terminal Blocks


The Circuit:



I am using this mod on my next computer project (soon to hit a forum near you). I will be using 2 AcuaXtreme pumps. First I took the impeller housing (by doing this you can run the motor without water) and carefully removed the plastic clip that hold the power cables in place at the base of the pump.




Next step, I took apart the back plate, bolted to it you find a circuit board with 3 hall sensors.



This mod will require the out-put signal coming from 1 of the hall sensors. I used the out-put from the middle sensor (yellow cable).



Now just splice, solder a long cable to it and insulate with heat shrink tube and re-wire the cable to the front. Note I did not solder directly to the hall sensor, this may burn the sensor. I put together the pumps without the impeller housing for testing.





Next step, I connected everything together.










Both pumps read an average of 4200 R.P.M. with power, and 0 R.P.M. without power, when resistance is applied to the impeller base R.P.M will decrease.






[size=-2]Disclaimer:
This mod will void any warranty on your pump. If you want to do it, do it on your own risk.
[/size]

 

That's an excellent idea for a very simple mod!!

 

That is such an excellent idea. Simple, cheap, effective. Ownage due here!

 

I forgot to ask this earlier but will this work for ALL brushless motor pumps providing the Hall sensors are accessible?
I'm thinking the C-systems pump specifically here.

Thanks

 

In theory it should work will all pumps with the hall sensor accessible, the C-systems MarkII pumps comes with r.p.m. monitoring cable.

 

Thanks

 

Very cool!
Any idea if it'd work for an Eheim?

 

Ooooh, didn't know that, thanks very muchly

 

A ULN2803 Darlington array chip is exactly that, an array. There's no need for a second 2803 since you can just use another input/output on the same chip as the other Makes this an even cheaper mod

Obviously this will mean that one of the "fan headers" that you connect to the motherboard will only have the rpm signal and no supply leads, since the darlington array will be powered by the other.

 

I don't have experience with those pumps, maybe if I can find some documentation on-line I be able to answer that, or some pictures of one Eheim taken apart.

 

That's a great find! Might do that to my MCP600.

 

Sweetness!

 

I don't know if this would actually work or not; it's based off the same principle though. Cyclometers (computers that calculate the speed of a bike) use a magnetic sensor on the bike frame to count a magnet mounted on a wheel spoke as it passes by with each wheel revolution. This is then compared with circumference to yield speed. Why not just mount this setup on the tip of a fan blade and in the housing, and bypass the use of a brush less pump? In effect you'd just be removing the sensor from the pump and placing on the fan. Sorry if I totally missed the point here, this is the first time I've seen RPM monitoring done this way, and I am a novice when it comes to electronics. I'm not knocking the idea at all, just trying to simplify.

 

The mass of the magnet would unbalance the fan... It would certainly cause noise, and probably cause bearing failure. Also, the Cyclometer would be an independant device which you would need to change your batteries frequently, where the hal effect trigger method will be powered from the motherboard. Finally, the cyclometer wants to report MPH or KPH, but not RPM. The hal effect trigger will report RPM, which is a much more relavant piece of information for either a fan or a water pump.

-TZ

 

Okay I see now, that would certainly make a mess of things. Thanks for explaining.