Free Fan, Save Money and reduce noise massively.

[Hatery1967]

Perhaps you could use a pressure differential switch. An old combi boiler would provide one.

This one has adjustment, but the outline shape makes them recognisable. It's job is to see the fan is running. In function, there is a diaphragm at the widest part. A cavity below and above it, each have a 4mm? pipe spigot, visible in white and grey here. The white one, connects to the fan at the inlet side. The fan sucks the diaphragm upwards. The grey connects to the outlet of the fan, to assist this movement with some push. The physical orientation of this device can alter the pressure needed to switch it. As can the adjustment. Extra vacuum can be found by taking that vac pipe into the air stream, pointing it downstream, and even flaring it out a little. Or a little venturi action, by narrowing the inlet just before the fan.
I recently fitted a 30w 7" pc fan into a case, using one to detect the fan is running. No effort. Just one pipe in the case, one pipe outside. The case was not sealed, or the fan that great. These are remarkably effective, and should have no problem sensing your tube fan. Offering enough sensitivity to even choose the run speed you want to switch at.
The contacts are spdt.


Thanks for the controller info. It's good to know. I really don't want to be drawing out heat, at the expense of RH. Though I'm tempted by the 69s VPD tracking, and duel zone, the 67 seems like all I need. I think the 69 even controls LED lights, which are another 0-10v or pwm device. Stock levels here n there, suggest the 67 may of even been superseded by the 69. One supplier just sold out cheap. Real cheap.

 

[Ca++]

I have a little more on the c67 wiring, for anyone wanting to chop one up..
A 4 pin ATX fan plug, often called a molex, fits the C67 that predates the move to a USB socket.
In a PC ($3 lead) they are coloured Red, Black, Black, Yellow.
That is Positive, Negative, and PWM. The PWM is a negative, not a live.
The yellow isn't wired from the AC provided fan.

This is deduced from the fans full speed operation while no controller is connected. The fan makes the 10v controller needs, and feeds some to the fans speed wire through a high value resistor. It's this that the controller is grounding away.

I have an EC fan that doesn't run without anything on the signal wire. The C67 doesn't put anything out. It grounds away. So I will be doing just this. A 100K from the 10v line to the control wire, to give it 10v for full speed. Then the control wire will also be taken to the C67, that can ground the 10v to nothing. Just short circuit it away to ground.

Anyone tackling this likely gets it by now, but bump me if help is ever needed.

I will repeat this in my EC fan thread, once it's actually done

 

[LeoBruno]

Perhaps you could use a pressure differential switch. An old combi boiler would provide one.

This one has adjustment, but the outline shape makes them recognisable. It's job is to see the fan is running. In function, there is a diaphragm at the widest part. A cavity below and above it, each have a 4mm? pipe spigot, visible in white and grey here. The white one, connects to the fan at the inlet side. The fan sucks the diaphragm upwards. The grey connects to the outlet of the fan, to assist this movement with some push. The physical orientation of this device can alter the pressure needed to switch it. As can the adjustment. Extra vacuum can be found by taking that vac pipe into the air stream, pointing it downstream, and even flaring it out a little. Or a little venturi action, by narrowing the inlet just before the fan.
I recently fitted a 30w 7" pc fan into a case, using one to detect the fan is running. No effort. Just one pipe in the case, one pipe outside. The case was not sealed, or the fan that great. These are remarkably effective, and should have no problem sensing your tube fan. Offering enough sensitivity to even choose the run speed you want to switch at.
The contacts are spdt.


Thanks for the controller info. It's good to know. I really don't want to be drawing out heat, at the expense of RH. Though I'm tempted by the 69s VPD tracking, and duel zone, the 67 seems like all I need. I think the 69 even controls LED lights, which are another 0-10v or pwm device. Stock levels here n there, suggest the 67 may of even been superseded by the 69. One supplier just sold out cheap. Real cheap.

Thanks for that

 

[Ca++]

C67 on fan speed one, is 24% of full speed. That is the lowest it will go. Most EC fans turn on at 10%. I really want fine control at lower speeds, and don't really care if I can get to full speed. I might have to get real brainy with this one, and find some way to re-scale the PWM. Though I have took ages to get this far, as I don't want a fan controller that needs a 3 day course to program the thing. I have too many important things to remember, without my fan speed being a task.
We will see. Right now, I'm just feeling a bit negative towards the things, as it's not doing what I want. Perhaps I should give it a chance. I find the presence of an instruction manual with a spine, not a staple, a bit sickening.


So.. what did I do. I'm going to presume anyone hacking one of these, has some basic skills. Though I will take questions, if they ever arise.
Looking at C67, I put a molex in the middle. It goes left to right, pos, neg, pwm, clueless.
The pwm seems to be ground. I pulled it up with 39K (random resistor) then I could see the duty cycle. Without pulling it up to pos (12v in this case) it seems to not register compared to either pos or neg. This makes sense, when you think the ACinfinity fan runs without the C67
Here is an EC fan

You see, an EC fan won't run without a signal on the control wire. It doesn't have the pull up resistor of an LED driver. So we must add one.
We take a 10K+ resistor, and offer the control wire VDC. Pulling it up to VDC, the fan then sits on full power.
The controller pwm wire also connects to the control wire. Pulling it back down again, when it doesn't want the fan on full speed. It seems the C67 does this at 5khz, which is right in the middle for most EC fans.

I'm not quite done with this yet, as I have not actually wired the thing to a fan. It's then that the resistors might need some fettling, but not below 10K, or you ground away more than 1mA, and many fans won't supply more than 1mA on that auxiliary VDC wire.

I should get out more

 

[exploziv]

Arduino can easily do the limited scale pwm you want.

 

[Ca++]

I can't even program the fan speed controller yet lol
I got around to the idea of lowering the 10v. Using a VR as a voltage divider, I could rapidly re-scale. One thing puzzles me though. Some of these 10v systems, actually use 12v external PWM control signals. In my mind, a 12v pwm signal, is already at 100% of 10v, before 90%pwm. I can't quite wrap my head around it. I suspected we were charging a capacitor, but this behaviour suggests a processor able to see the signal is between 1-10khz, and under these conditions, ignore the actual voltage. My divider would therefore not work. This actually makes compatibility between hardware manufacturers easier. Some controllers might only give 10v, but be some distance away, getting volt drop. Others might be 12v. Both need to work, but at different voltages. I had already been looking at the problem of resistor sizing, in relationship to the internal resistor sizes that tie the signal to ground through 100K, thus the 10v is already part of a divider. Perhaps I should just cross all this out..

It's actually a $5 board, to turn pwm to 0-10vdc

PWM to Voltage Converter Module 0%~100% to 0~10V

It is designed for converting the PWM digital signals into 0 to 10V analog signals. The output voltage is regulated by adjusting the duty ratio of the PWM. Select the PWM signal input level range through short-circuit. It can be used as signal interface switching for PLC or other industrial...

www.botnroll.com

Still not scaling it there, but getting back to analogue, makes the VR work.
I still need to run the fan and see what 24% looks like. I have one needs about 14% to start up, and in fairness, It's never on that low.

A pair of these fans is now $200 but delivery is slow at that price. I can get them locally, the very same, for $250 each. A single from the factory, flown over, is about $165. These are UK prices, and the USA is probably a bit more direct. It's all shipping. The fan is $40-$70

 

[Ca++]

May have need for a processor. I have fallen upon an error, that I expect is common.

Speed1=23.5%
Sp2=31.5%
3=39
49
56
64
72
80.5
88.5
98

Ignoring the impossible spread of measurements there, the motor does see PWM % as how fast is should spin, in % of maximum.

The problem is, moving from speed1 to speed2 isn't a 10% increase. From 24-32 is near 40% faster.
1-2 = +40% faster
2-3 = +30%
3-4 = +25%

+10%
+10%
+10%

40% Jump is an oversight. If I can only go from 24 - 99 in 10 steps, I would like 15% steps

sp10=100
sp9=85
sp8=72
sp7=61.5
sp6=52
sp5=44.5
sp4=38
sp3=32
sp2=27
sp1=23

Each speed increase 15%.

It's logarithmic, so I might be able to do something with the numbers. It's really for a processor though

 

[exploziv]

Arduino platform would just allow you to set a new 0 to 100 scale, and mask that over any interval of the scale the fan already has, or just pick 10 points and use those as your fixed 10 speeds from which to chose.

 

[Ca++]

I might be able to do something with an analogue VU display driver. It would give me the curve, from a linear input. I'm hearing the smaller arduino chip look up tables are 8 bit, so lack the resolution. Though I can't work one anyway. This non-linearity is found in base-emitter current. Which the VU meter driver likely uses. If they still exist..
I did start sketching out the analogue version of the look up tables, but it was hideous. What I could use, is the bar graph style VU driver. PWM to DCV with just caps and resistors for smoothing. Then the bar graph driver. Which is 10 LEDs, but I fear the non-linearity of the PWM from this C67, won't align properly. It's a bad starting point. They did a poor job. Which is surprising, as the items really quite polished to look at. They just didn't use it though. Things like the screw holes being positioned wrongly, to be hanging it like a picture. They give you screws though, if you can find some fixings for your tent wall.

These are the issues I have found, with it sat on my bench. I just fitted the fan without it. I don't really have time to be fixing it, and wonder if the later models suffer with the same inadequacies. As I would just buy the new one, if it's right. Who is going to know though.

 

[Ca++]

I tidied up a drawing, as I have proved this works now.

Inside the controller, the PWM wire is being connected to ground, then to nothing, rapidly. The resistor makes sure that when the wire is connected to nothing inside the controller, it is still connected to 12v outside the controller. Thus, the pwm wire is moving between 12v and ground states.
The ACinfinity fan has this resistor internally, but to use an industry standard fan, we need to add it ourselves. Another option would be to put it within the fans terminal box. Connecting the PWM wire, to the 10vdc the fan provides, not the 12vdc I have used at the controller. That may actually be a better idea, as failure of the controllers power, would put the fan on full power. Not stop the fan.

It should be noted, the AC67 is a 10v device, not 12v. I just used 12v, as it's common. The ACinfinity fan usually provides this 10v. The industry standard EC fan has a 10v auxiliary, but it's not enough to power the ac67 itself. The 10v from the industry standard fan, is good for 1mA usually. It won't even light an LED. You will bust something if you try and run the AC67 from an EC fans 10v auxiliary output.

100K is typical of the VR's used in 0-10v control. I tried a 39K, which could be considered stress testing. Use 100K and see how you do. The tach wire is there (fg) if you want to check full rpm has been reached. I think it will also need 100K pull up.