Computer power supply as 12/5/3.3V whole house power supply

[csa02221862]

I'm wanting to do this but think there should be more to it than this, such as various protections.

Soft fail-over to my solar setup would be nice too.

http://www.instructables.com/id/Convert-an-ATX-Power-Supply-Into-a-Regular-DC-Powe/

I know several of you have done this.

Thanks,
Richard

[m26872]

@csa02221862 How do you deal with voltage drops and I2R power loss if your using these low voltages for a "whole house power supply" ?

[csa02221862]

I know petewill has done this and was hopping he would comment. hat is one of my concerns. I'm mainly interested in the 12v.

[m26872]

We should ping @petewill then. :smile:

[AWI]

@csa02221862 I have a setup with 24v supply and one with 12v with a cheap adjustable booster to 15v. In my nodes I use a buck converter to get to the 5v/12v level. The extra voltage on the line compensates for losses.
The buck/boost converters are very efficient but tend to produce a lot of "high frequency" switching noise on the power lines. For the sensitive MySensors nodes I always use a linear LDO to be sure (AMS1117 / 662k/ mcp1700). For most 12v uses there is no need to filter the noise (i.e. Light,LED, relay)

A "pico atx" supply (search aliexpress) is also worth looking at..

[petewill]

@m26872 said:

We should ping @petewill then. :smile:

Sorry for the delay! I didn't see this until now.

I am using a computer power supply for most of my projects. I use both the 12V and 5V but haven't had a need for the 3.3V yet. I have 12V cable runs that are probably 60-70ft and I have had no issues powering my blinds and various LED projects for the last 2+ years. I am using the 5V for motion sensors, irrigation controller, rain gauge, etc all over my house and have also had no issues with them. Depending on the size of your house it is a very cheap way to get good power (in my opinion). I am using an old (free) 220 watt power supply.

For protection I have fuse blocks between the sensors and the power supply.

Here is an old, poor quality picture of my setup.

[AWI]

@petewill These are the best pictures...:open_mouth:

[CrankyCoder]

@petewill do you have videos up of that power supply build?!

[petewill]

@Jason-Brunk said:

@petewill do you have videos up of that power supply build?!

No, not yet. It's on the list but keeps getting bumped. I will try to do it soon but I already have some projects in process so no guarantees as to when. :)

[CrankyCoder]

@petewill sounds good. definitely like the idea. how far are your longest runs?

[csa02221862]

You are using standard cat 5/6 for the power run? Can't wait for the "How to video". Looking forward to replacing
all those 'wall warts'. What fuse rating do you use? Dose it vary, or do you use a standard to protect against short circuit?

[SuperKris]

I'm not sure i really understand... Are you talking about powering all the mysensor modules through out the whole house by a single source? If so i can hardly imagine why one would like to do this. This would completely go against the mysensors idea. Such a system would be more fragile, use more power than necessary, and just be very ugly and overcomlicated because of all the wiring.

If your talking about usage on a switchboard only, it makes a lot more sense. Still, arduino's and all compatible systems use a very low amount of energy. I power a raspberry pi 2, 2 arduino's, a chip amp, and a couple of other modules with a $ 2,- step down converter of aliexpress. The consumption is so low, the load indicator doesn even switch on most of the time.

In other words, unless your powering heavy equipment, a computer PSU is a huge overkill. I would recommend buying a cheap industrial DIN rail supply of aliexpess or another source. In the end this might even be cheaper. Its saver and a whole less work for sure!

[petewill]

@Jason-Brunk The longest runs are 60-70ft

@csa02221862 No, I'm using 16 and 18 gauge wire depending on the current draw. I use 1 or 2 amp fuses depending on the draw and wire size.

@SuperKris I use this to power my blinds and 12v LED lights throughout my house. I also use it for sensors where it's easy to pull power to. This saves me from having to replace batteries or use additional wall warts. For example, I have a motion sensor in almost every room in my house and they are all powered by the power supply because it's easy to get power to them. The computer PSU is used because it was free for me.

[sundberg84]

@petewill - this is cool!
I +1 for your video on this ;)

[csa02221862]

Any update on the video?

Thanks for all the good videos you have done to date.

Richard

[petewill]

@csa02221862 Working on it now. Hopefully I'll have it finished within the week.

[csa02221862]

PERFECT!

Thanks.

[sundberg84]

@petewill - Cant wait!! :)

[petewill]

Finally finished! Here is the post: https://forum.mysensors.org/topic/4691/low-voltage-whole-house-power-supply