Hello fans uh, hang on hello fans. Yes, this video is about fans particularly uh. This sort of fan these 120 millimeter square fans - 12 centimeters - that is uh this one's one inch thick. So that's 25.4 millimeters, this one's an inch and a half: that's 38 millimeters and they're all different power ratings.

So this one is 2.7 amps and this one is just 0.8 amps. Now these are the four wire fans which have ground 12 volts and also a tacho signal and also a pwm input so that you can control the speed of the fan. So these are computer case fans and but my interest in in them is more to do with cryptocurrency mining uh, because these fans are used on the cryptocurrency miners. So here's a cryptocurrency miner.

This is an antminer v9. This mines bitcoin using the shah, 256 algorithm, and these things get quite hot. You can see there are lots of heat sinks in here this one's seen quite a bit of action and has a few dead animals in there, but i bought this. It was very cheap.

It was 30 quid just before the recent resurgence in crypto currencies and i bought it really just to rob the fans off it. I don't actually think i've powered this one up at all uh. This particular model takes two fans one on each end. So it's a sort of push pull arrangement um.

There are two connectors here and so, as this thing warms up, it has temperature monitoring inside and, as it starts to get warm, it will increase the pwm on the control pin to the fan. The fan will speed up and it also monitors the tacho signal to ensure that the fan is actually turning and turning at the correct speed. But today i'm not going to mine crypto. With this i am mining crypto elsewhere, but that's just because the sun's out uh yeah, i'm just going to use this as a sort of heavy base to screw my fans onto it and test them play with them.

So as well as something to attach my fan to and the fan itself, i also want the contents of this envelope which i've not even opened yet um. I bought this on ebay and it is a fan controller, or at least that's what it's meant to be. Let's have a look right. This looks interesting, a little circuit board with a connector for the fan.

Let's check this out, there's also a thermistor here on the end of a piece of wire with a two pin: connector there's the board. I've got some leds here and a push button and i think you just press the button and it goes through different pwm values to control the fan, and this is a four wire fan controller, so my fan will connect there. I need to put 12 volts on there and then i should be able to control the speed with that, and i think if you plug the ntc in it goes into some sort of automatic temperature control mode. So we'll give that a try.

So what do we have on here? Um? The microcontroller has had all its markings removed, but that's going to be some sort of st microcontroller. I'd have thought. There's a 78 lo5 regulator up in the top corner there that's to take the 12 volts coming in turn. It into 5 volts for the microcontroller.

Interestingly, i believe that on these fans, even though the power supply is 12 volts, the pwm signal, which i believe is blue - i can't quite remember um - is a five volt signal. I believe, and then the taco is open collector. So that that, actually you pull it up to whatever you want, i suppose you could put it up to five put it up to 12 or even more uh with a resistor and then um. The transistor in the fan will just periodically pulse that low.

But yes, a peculiar arrangement, 12 volts power and five volts for pwm. I presume this uh does that so just went out to the shed to get some of these um long m3 screws which will go through the fan and attach it to the front plate of the miner. Also a fan guard because, when these fans are this way around, you don't want to put your fingers in here when it's running at full chat because it'll chop them off. So i'll put the fan guard on now.

I've taken to writing some of the details of these fans on the blades, because when the fans are this way around uh, you can't see what fan is actually in the machine. This one is actually if the camera would behave, uh 1.6, amps, so we've got a range of different currents and i want to try and settle on the ideal fan. That's going to work in all my miners anyway. So, let's start with this one: this is the 2.7 amp and i believe the parameters for this are up to 3 amps.

I think it said that in the listing - and that's really just about these wires and the traces on the board, because it just feeds 12 volts straight through onto the fans, red and black terminals um. So this should be okay, i'll, take 12 volts from a suitable power bank. Now i just wanted to check that the 12 volts coming from my power bank is actually 12 volts because some of them are a bit high. But, oh this one's absolutely fine, that's 11.96 or seven good 12 volts! Let's plug that into that connector right! I'm going to get my 12 volts on a plug which can go into this socket.

So, let's power the board up and see what it does: um. Okay! So the number two red light has come on. If i press the button, it goes to number two flashing three but then number two flashing, so something's not quite right. Maybe it's because it's not seeing the taco signal.

I'm not sure whether this does monitor the taco signal. I thought that just went straight back to that pad there, where you can monitor it with um. I don't know scope frequency counter, that sort of thing, but i'll plug the fan in and see what happens. Okay, let's plug it in and the fan powers up now.

Can we change its speed? No, it seems determined to be on number two. Maybe i have to press and hold number one flashing. Slowly, no change in fan, speed, press and hold number one flashing. A little bit faster, i suppose i should read the um listing for this, and i will put a link in the description below to this item.

I got it on ebay. Well, i've worked something out, and that is that if you press the button now, if you double click it, it goes down lower speed. If you single click it, it briefly pulses the led number three and it increases in speed. So each time i click it.

It's increasing the pulse width and the fans getting faster like so, but i still think i should read the listing because i don't really know what's going on right. I've plugged the temperature sensor in now, and i've noticed if i switch my soldering iron on which i'll do and hover that under the temperature sensor in your own time, temperature sensor. Well, it's not doing it now what's going on. Oh, i think.

Ironically, the fan was sucking the heat away. So let's try that again with my hand in front of the fan warm the thermistor up, and there goes the fan increasing in speed and decreasing in speed when the thermistor cools back down again. So it's kind of doing some sort of temperature related thing, but i haven't quite fathomed out how this led works. Yet right.

I've done a series of double clicks to get this down to the minimum pwm. So this thing's crawling now, let's see whether putting the uh soldering iron under the temperature sensor increases the pwm and maybe that's not on. I don't think that is on up comes the temperature 250 300 350 and with the fan barely running it shouldn't be sucking the heat away. But now that doesn't seem to be doing anything.

Oh there. It goes because, if i take my hand away it sucks the heat away from the temperature sensor and does temperature control so yeah, i think that's working. I think you set the default speed by doing a series of single click. The single clicks.

Take it up. You can see the number three light flashes, you set its default static, speed and then the temperature sensor will work as a feedback controller from that point onwards. Oh, this is quite complicated. I think um you use the up and down buttons, which is a single click or a double click, to set the sort of standby speed.

Well, it's currently on minimum pwm. Then you go into the setting for this parameter, which is the starting temperature at which fan speed, increases start and i've set it to 30. That's the default. Apparently, then you go into this parameter.

You get into this one with a long press you get into this with another long press, and that appears to set the slope or the range of temperatures over which it varies, the pwm speed from zero. Now zero actually is not quite zero. It runs the fan at a low speed, but from the lowest speed to the highest speed and i've set my range. The default is 20 degrees.

I've set it now to just five degrees. So when you heat this thing up above 30 between 30 and 35, it ramps the fan up between the slowest speed and the fastest speed, and that seems to work quite well. Let me show you so just to check my settings. You do a long press and then it's flashing slowly on number one.

That means the starting temperature is 30 degrees, another long press and it's flashing quickly on number one. That means that there's a five degree uh ramp from lowest pwm to highest. Now you can change these by clicking and it goes in a binary fashion like so or double clicking, and it comes back down. Well, i want this minimum one and then to save it, you press and hold again, and that takes you out of the sort of programming mode back into the setting, the baseline speed mode um, and so the baseline speed is set to the minimum.

So if i start warming this up by putting my soldering iron on, that's oops, don't want to melt my water uh just get this to a reasonably warm temperature and start warming up. The thermistor slightly pointed the fan away. Now, let's go up to the end, and so the fan ramps up to its maximum speed over the course of a relatively small range of temperatures between 30 degrees and 35 degrees. Let's put this back to its default, so long press, that's the 30 degrees.

Another long press, that's the 5 degrees, so let's take that up to where it was initially, which was there i'll, save that, and so now that should be more difficult to coax up or it should go up more gradually. So, yes, it does go up, but it goes up over a 20 degree range so from 30 to 50, rather than from 30 to 35, when you set it to the most temperature, the most sensitive setting so yeah. The first parameter sets the starting temperature and the second parameter sets the slope of the curve over which this thing controls temperature, that's actually quite clever. Okay, so i've set this again to its most sensitive.

So not much heat will make a big change in fan speed, but i'm going to change the fan now because i bought this fan and it was a bit of a dud for mining equipment because it's really not powerful enough. It's only 0.8 amps, so just wondering whether this has a lower top speed and therefore a lesser ability to shift air. So i'm going to connect this one up and see what this thing does right. This fan is slightly complicated by the fact that it's uh only one inch rather than an inch and a half, so i've had to put some nuts on these long screws.

I don't have any different length screws, but let's power this one up and see what it sounds like. Oh, i think i was conned with this fan. This little 0.8 amp fan didn't work very well on the miner. The miner complained about it and i think that's because it's not pwm at all, so i'm raising the pwm.

It came on quite fast when i first started it and it's absolutely doing nothing. I think this is a two-wire fan or possibly a three-wire. No 3-wire has pwm and not taco. I think i can't remember, but it's just not doing anything yeah.

I think this is a corn. I was conned right. Finally, this is the 1.65 amp fan on minimum pwm, the two lights on there yep this is on. So, let's put that under the temperature sensor, try and get it above 30 degrees yeah that one ramps up nicely and then should slow down once this thermistor cools down yeah that one is also good now.

Finally, this fan, which i bought recently from an ebay seller. I bought a couple of them uk seller up in leicester actually, and these are supplied with this strange inline, molex connector and this connector is odd because it's not like your conventional molex, there's the conventional molex, the white one, and it has the two ribs at the Far ends this black one has one at the far end and one in set a bit, but then they've provided this adapter cable um, which can take that molex connector. So if anyone knows what this rather strange, modified, molex connector was used for uh i'd be interested to know, but that brings it out into the conventional connector. Now.

The only issue with this is it's black red, blue, yellow, whereas all my other fans are black red, yellow blue, so the color scheme is just slightly different, but it appears to work without any wire swaps, so i'll plug this one in and see what this one Does and uh yeah this one appears to work as well. That's on minimum settings very quiet on its minimum setting, let's get some heat under the thermistor and up it shoots to full speed, so that works. One thing i've noticed is that the um connectors inside this black plug aren't in very good condition. They look a bit corroded and some of them are, but just pull out like that black one doesn't seem to have its barb anymore.

I think the barb's gone missing. Yeah, there's just a hole in there um, but it doesn't matter because i'm planning to cut these solder them and heat shrink them to take that connector out because it's an unnecessary connector. So there we are. That's some fans tested using this little tester module, which seems quite neat, and i did buy one of these modules from another seller and it was supposed to be a four wire and they just sent me a three wire because they got it wrong.

Uh that had a temperature sensor as well, but the problem with this one is it says max 0.8 amps, which is next to useless so uh you don't always get what you order, and so that's it for this video cheerio.