I'm just an enthusiast, I want to build a simple fan operated by a thermostat.

Thread Starter

Albertoinbox

Joined May 29, 2020
21
Hi guys,

sorry to drop in on your community like this. I'm not an engineer but I have always been fascinated by electronics and always loved to tinker with it whenever I have an idea. Cant remember how many stereos I burnt back in the 80s trying to add as many speakers as I could! But my very limited knowledge cant take me very far. I chose to take another path and when it comes down to the real deal I'm lost.

I just would like to connect a thermostat to a 80mm PC fan. I would like to operate it on 5v which is the standard USB wall charger power supply.

I want to keep it simple and cheap as possible.

I found this thermostat on eBay and it looks like what I need. It looks like I must power it with a positive and a neutral and the other two connections perhaps are + and - for the fan?

Am I in the right place to get help?

Thank you so much.

s-l1600-2.jpg
516BeKke1JL._AC_SL1000_.jpg
81tOnMlrB6L._AC_SL1500_.jpg
 

drc_567

Joined Dec 29, 2008
844
... A possible difficulty ... The + power terminal on the board picture indicates that +12 volts is required for normal operation. Some additional documentation or reference material could be useful.
 

ericgibbs

Joined Jan 29, 2010
10,042
hi,
For that Temperature module.
Use Terminals +12V and GND as the 12V DC power input, to power the Module.

The K1 and K2 Terminals are the N/O pair of the Relay contacts..
You can easily confirm that by using a Ohmmeter, which should read Open Circuit

To operate a 5V DC Fan, Connect a +5v supply to K1 and one one lead of the FAn to K2, the other Fan lead goes to 0V of the 5V supply.
As you are using a USB wall charger, that is the 5V supply for the Fan

Do you follow that OK.?
E
Post a link to the site where you ordered the module, we can then double check.

Note: On some of those modules, the K1 and K2 are the normally closed pair of relay contacts N/C , thats not a problem, the Module will switch On/Off at the SET temperature

Typo corrected, Thanks for the Heads Up, Dick...:rolleyes:


Update:

Checked the identical module I have in my stock. K1 and K2 are Normally Open relay Contacts...
 
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Thread Starter

Albertoinbox

Joined May 29, 2020
21
Hey DRC, thanks so much for stepping in!

I found the same board in a 5V version, I'll attach an image. I though that if I kept everything 5V then 5V would be enough to power it all.

I would like that when the temperature reached a certain set number the fans would turn on and wouldn't turn off until the temperature lowered below that number.

This is what I would like to do:

Fan.png

I'm not sure if its 5V really or they attached a converter:
Screen Shot 2020-05-29 at 12.50.30 AM.png
 

Thread Starter

Albertoinbox

Joined May 29, 2020
21
hi,
For that Temperature module.
Use Terminals +12V and GND as the 12V DC power input, to power the Module.

The K1 and K2 Terminals are the N/O pair of the Relay contacts..
You can easily confirm that by using a Ohmmeter, which should read Open Circuit

To operate a 5V DC Fan, Connect a +5v supply to K1 and one one lead of the FAn to K2, the other Fan lead goes to 0V of the 5V supply.
As you are using a USB wall charger, that is the 5V supply for the Fan

Do you follow that OK.?
E
Post a link to the site where you ordered the module, we can then double check.

Note: On some of those modules, the K1 and K2 are the normally closed pair of relay contacts N/C , thats not a problem, the Module will switch On/Off at the SET temperature

Typo corrected, Thanks for the Heads Up, Dick...:rolleyes:
Brilliant! I think I got it.

My only doubt would be if I will be able to find the right power wires to connect when I strip all these different cable types. Never done anything rather that black and red, at least not that I haven't burnt out. Will it be easy to identify? I don't have my multimeter.

I dont have the modules yet, not until I figure this out:
https://www.ebay.com/itm/W1209-Blue-LED-DC-5V-Thermostat-Temperature-Switch-Thermometer-Controller-Sensor/163389910909?hash=item260acc2f7d:g:4ykAAOSwIUFb9qhz&autorefresh=true

Thanks
 

Alec_t

Joined Sep 17, 2013
11,295
The "5V" unit shown in the post #6 link looks to be a 12V unit actually, but other units from the same stable do show '5V' on the power input terminals and the relay. Make sure you get the right one.
 

Tonyr1084

Joined Sep 24, 2015
4,535
First; Welcome to AAC. You said:
Hi guys,

sorry to drop in on your community like this. I'm not an engineer
Some of us are but many are not. You're among good people here, and we love to help.
I just would like to connect a thermostat to a 80mm PC fan. I would like to operate it on 5v which is the standard USB wall charger power supply.
That's doable assuming two things: Your supply can deliver the amperage needed by both the control board and the fan. In post #5 you depict using two fans. As you learned about adding more and more speakers to an amplifier - you will achieve the same results by adding more and more fans. If the supply source can not handle the required amperage then either the voltage will fall below an operational level OR the system will burn up.
I found the same board in a 5V version, I'll attach an image. I though that if I kept everything 5V then 5V would be enough to power it all.

I would like that when the temperature reached a certain set number the fans would turn on and wouldn't turn off until the temperature lowered below that number.
The picture in post #5 shows a 12 volt supply. [edit] You said you can find the same board in a 5V version; if that's the case then you can power it from 5V. But the fans? What voltage do they require? [end edit] The board clearly requires 12 volts to operate. Since you want to keep the costs down - you can easily pick up plenty of 12 volt wall warts from places like Xfinity and DirecTV stores. They take in old equipment all the time, most of the time along with 12 volt supplies that they don't reuse. Simply ask them for one of these used power modules and you're likely to get at least one. Sometimes I can walk away with a couple of them.

I have a question for you - you say you want to power this project with a USB cable. Yes, that can be done, but it's not going to be very useful. Most fans in a computer operate on 12 volts. I don't recall ever pulling a fan from a computer that was 5V. And a USB cable isn't meant for high amperage workloads. It would be as easy (if not easier) to use 12 volts. But the temperature circuit board operates on 12 volts (see edit above). The relay contacts can operate any device you connect through it - up to the rated voltage and amperage listed on the relay. 20A @ 14VDC or 5/15A @ 250VAC. That doesn't mean you need that kind of voltage, that's just what the switches inside the relay will handle. As for the "5/15A" - (me personally) I'm not sure exactly what that means. But since your plan is to use DC, 12VDC will be absolutely fine because at that voltage the switch can handle up to 20 amps. And you're probably not going to use that kind of amperage. But even if you use 5V, the relay will have no issues (that I can see).
 

Tonyr1084

Joined Sep 24, 2015
4,535
Yeah! BMS (Bi-Metalic Strips). An old thermostat from someones old heating system. Assuming the ones you can get a hold of are at the temp range you want.

Here's one from Lowe's you can get today.

In post #5 you drew 75˚. We don't know if that's F or C. If it's C then 75˚C = 167˚F. In that case - you might want to find a thermostatic switch from a very old furnace, one that requires substantial temperature before switching on the fan. Off hand I don't know what they're rated at, but I've had a few in the garage for a long time. Just a few months ago I cleaned house (the garage) and got rid of a bunch of stuff I never use.
 
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Thread Starter

Albertoinbox

Joined May 29, 2020
21
hi,
That White module is a Mains to 12V DC , 0.1A converter.
E


Update:
How many fans are you using.???
Thanks, I recognize it as such now.

I would like to have two options, one with one fan and the other with two, so the person can chose if he wants more or less cooling.

I would like to know if I can achieve that having identical setups (5V power supply) for both, just adding one or two fans.
 

Thread Starter

Albertoinbox

Joined May 29, 2020
21
First; Welcome to AAC. You said:

Some of us are but many are not. You're among good people here, and we love to help.

That's doable assuming two things: Your supply can deliver the amperage needed by both the control board and the fan. In post #5 you depict using two fans. As you learned about adding more and more speakers to an amplifier - you will achieve the same results by adding more and more fans. If the supply source can not handle the required amperage then either the voltage will fall below an operational level OR the system will burn up.

The picture in post #5 shows a 12 volt supply. [edit] You said you can find the same board in a 5V version; if that's the case then you can power it from 5V. But the fans? What voltage do they require? [end edit] The board clearly requires 12 volts to operate. Since you want to keep the costs down - you can easily pick up plenty of 12 volt wall warts from places like Xfinity and DirecTV stores. They take in old equipment all the time, most of the time along with 12 volt supplies that they don't reuse. Simply ask them for one of these used power modules and you're likely to get at least one. Sometimes I can walk away with a couple of them.

I have a question for you - you say you want to power this project with a USB cable. Yes, that can be done, but it's not going to be very useful. Most fans in a computer operate on 12 volts. I don't recall ever pulling a fan from a computer that was 5V. And a USB cable isn't meant for high amperage workloads. It would be as easy (if not easier) to use 12 volts. But the temperature circuit board operates on 12 volts (see edit above). The relay contacts can operate any device you connect through it - up to the rated voltage and amperage listed on the relay. 20A @ 14VDC or 5/15A @ 250VAC. That doesn't mean you need that kind of voltage, that's just what the switches inside the relay will handle. As for the "5/15A" - (me personally) I'm not sure exactly what that means. But since your plan is to use DC, 12VDC will be absolutely fine because at that voltage the switch can handle up to 20 amps. And you're probably not going to use that kind of amperage. But even if you use 5V, the relay will have no issues (that I can see).
Hi Tony, thanks for the warm welcome. I feel more comfortable now, dont want to go around annoying people.

Thanks for letting me know from the start its doable, thats a relief. Thank you for the lesson also.

I plan on having two models, single and dual fans, no more than that. (No more burning stuff) I just need to confirm it'll be alright with the two fans with everything as equal as the single fan version. To reduce cost and labor it would be best if I could just share the same one fan setup with two fans and just add it, instead of having to have different components for the two fan model because it would require more than what the single version can handle.

I see the picture shows a 12V version but I guess its just because some of these guys that sell 12V and 5V versions dont care enough to upload the actual two different product pictures. So its probably just the wrong image but I'm positive I will receive a 5V version. If you need to see the image of the actual 5V board to check the specs I will demand it for you, just ask.

The fact that I would like to use 5V instead of 12V is simply because I do not want to add the cost or bulkiness of a power supply to the product. Nowadays everyone has a spare 5V wall charger at home they could use which would make for a more versatile, practical and cheaper product. I understand it would still have to have a minimum amperage, and the majority come in very cheap low amp versions, but thats a far less complication. Even if I have to ship it with its own USB charger it will still be cheaper and smaller. Apples USB 5V charger is 1AMP but I have USB chargers with 3AMPs:
IMG_9409.jpg
IMG_9406.jpg

I have found 80mm fans specific in 5V! Check this guy out, he's supposed to be super quiet:
81IJBcPPoAL._AC_SL1500_.jpg
 

Thread Starter

Albertoinbox

Joined May 29, 2020
21
Yeah! BMS (Bi-Metalic Strips). An old thermostat from someones old heating system. Assuming the ones you can get a hold of are at the temp range you want.

Here's one from Lowe's you can get today.

In post #5 you drew 75˚. We don't know if that's F or C. If it's C then 75˚C = 167˚F. In that case - you might want to find a thermostatic switch from a very old furnace, one that requires substantial temperature before switching on the fan. Off hand I don't know what they're rated at, but I've had a few in the garage for a long time. Just a few months ago I cleaned house (the garage) and got rid of a bunch of stuff I never use.
Thanks guy for trying to make it simpler, thats the way to go. I checked it out and it looks great, specially from a solid company like Honeywell.

But $40 (tax) on a single component would defeat the project cost wise. Besides, I couldn't add a finished branded product to my product. It would look like a Honeywell product. It would also add a huge footprint to my product due to its size and shape. I want to keep a low profile. The fan are going to be in a horizontal position and it will be only 30mm high, I want to try to keep it that high, so I must fit everything within the casing. Im a designer and form and function are paramount to me.

But your idea is interesting, if there is a simpler way to do this I'll go for it. I just need the fans, the USB power and the thermostat.
 
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Thread Starter

Albertoinbox

Joined May 29, 2020
21
Yeah! BMS (Bi-Metalic Strips). An old thermostat from someones old heating system. Assuming the ones you can get a hold of are at the temp range you want.

Here's one from Lowe's you can get today.

In post #5 you drew 75˚. We don't know if that's F or C. If it's C then 75˚C = 167˚F. In that case - you might want to find a thermostatic switch from a very old furnace, one that requires substantial temperature before switching on the fan. Off hand I don't know what they're rated at, but I've had a few in the garage for a long time. Just a few months ago I cleaned house (the garage) and got rid of a bunch of stuff I never use.
I put 75 there just to help identify it as a thermostat, I'm sorry.

The temperature to which the thermostat will be set to will be within 72-78º Fahrenheit. In some rare occasions, people might set it as low as 60º, but I wouldn't need to guarantee it could lower the temp that much.
 
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