Here is a new twist to using an ATX Power Supply

[sam_sam_sam]

Re: Here is a new twist to using an ATX Power Supply

“ I finally got my h**d out of my a** and now understand how use the program “


Well I finely got half of a project done that I have wanted to do for a long time

This object was created with Windows 3D Builder software

I wanted have a way to test 18650 batteries charging a phone or tablet and use the battery testing machine that I have to see how long the running time would be

Now I have to work on the back cover for this project

[clearchris]

Re: Here is a new twist to using an ATX Power Supply

Great minds think alike. I just did this the other day, it's a four port USB charger based on a laptop power supply and 4 usb buck converters. Pretty happy with the design, I'm going to make some light changes before releasing. It was really quick too, I used my previous design of the benchtop power supply as the base.

[sam_sam_sam]

Re: Here is a new twist to using an ATX Power Supply

Like minds do sometimes think a like

I like what you have here but what did you use to convert it down to 5 volts ( I think I know which ones you used but just in case you found something different )

Can you post a link to them

I do have a question for you about your design with the USB cut outs did you make it fit the length of USB housing or did you do something different ( if you did something different how did you keep the USB connectors in place )

The only problem I had with what I did was the first time I plug in the USB cable it fit a little tighter than I would have liked but after installing it and removing it a few times it was easier to do

( I was very pleased with the way it turned out ) I just can not decide how and what I want to with bottom of this enclosure ( but I am leaning towards installing banana jacks for bottom of this case and putting a ON and OFF switch so I do not have remove the plugs in the banana jacks all time )

Did you tie the two center pins together on the USB connector or did use resistor network for your device that you plug into it

I want to build something like this for my truck to fast charge my phone and tablet but not quite as big as how you made yours but I want to barrow your idea

One other thing did you remove the switching power supply board from it case and installed in your enclosure or did you use a power jack to power the UBS enclosure

[clearchris]

Re: Here is a new twist to using an ATX Power Supply

Sure, here you go. I have 4 of them in there. The can get warm, so I added vents, haven't had all of them going at once yet. Listing says 3a, but the datasheet for the chip says 1.8a. They work well though. There are some others similar, but without caps, don't get those.

https://www.ebay.com/itm/DC-DC-Buck-...Y/262503275432

[budm]

Re: Here is a new twist to using an ATX Power Supply

Do you have the schematic on the Buck converter?
The bad part about Buck converter is that if the Active switching shorted out, it will dump the full input Voltage to the output, you should install protection device on the output in case the short circuit happens.

[sam_sam_sam]

Re: Here is a new twist to using an ATX Power Supply

Do you have the schematic on the Buck converter?
The bad part about Buck converter is that if the Active switching shorted out, it will dump the full input Voltage to the output, you should install protection device on the output in case the short circuit happens.

Thanks for sharing information

Are these buck converter any good because I was thinking about getting a couple of them for a project I have in mind

https://www.ebay.com/itm/4V-38V-to-1...53.m1438.l2649

Or

Something like this

https://www.ebay.com/itm/2pcs-XL4015....c100005.m1851

[clearchris]

Re: Here is a new twist to using an ATX Power Supply

There's a protection diode on the input, not sure if that's sufficient though. Otherwise, the circuit is rather simple. It uses an XL2001 buck converter, which does have output short detection at least. That might be what you are talking about or it might be a short in the device, I can't tell from the datasheet.



Here's a top view of the converter, and it's single sided, so nothing hidden underneath.
https://i.ebayimg.com/images/g/I0sAA...uu/s-l1600.jpg

[sam_sam_sam]

Re: Here is a new twist to using an ATX Power Supply

There's a protection diode on the input, not sure if that's sufficient though. Otherwise, the circuit is rather simple. It uses an XL2001 buck converter, which does have output short detection at least. That might be what you are talking about or it might be a short in the device, I can't tell from the datasheet.



Here's a top view of the converter, and it's single sided, so nothing hidden underneath.
https://i.ebayimg.com/images/g/I0sAA...uu/s-l1600.jpg

Here is what I would suggest doing is put a 2.0 amp fast acting fuse on input of this module just in case something goes wrong

How did you mount these modules in your enclosure

[clearchris]

Re: Here is a new twist to using an ATX Power Supply

A fuse is a pretty easy solution, good idea.

I designed a cradle that fits that module pretty much perfectly. There are two screw holes for a small plate with a lip that holds the back in. The front is held in place by the USB cut-out. There are four spaces, the bottom one is shown with the cover in place.

[sam_sam_sam]

Re: Here is a new twist to using an ATX Power Supply

A fuse is a pretty easy solution, good idea.

I designed a cradle that fits that module pretty much perfectly. There are two screw holes for a small plate with a lip that holds the back in. The front is held in place by the USB cut-out. There are four spaces, the bottom one is shown with the cover in place.

Very nice

[clearchris]

Re: Here is a new twist to using an ATX Power Supply

Yeah, if you are ready to gradute from MS 3d Paint, freecad is nice imho, I'm not ready to post the files to this one, but the box it's based on (including the usb buck converter mount) is up here:

https://www.thingiverse.com/thing:4126979/files

Design files included, so you can open it in freecad, not just the STL.

The real trick in designing for 3d printing is no overhangs. You can see the ways I designed it to accomplish that.

[budm]

Re: Here is a new twist to using an ATX Power Supply

There's a protection diode on the input, not sure if that's sufficient though. Otherwise, the circuit is rather simple. It uses an XL2001 buck converter, which does have output short detection at least. That might be what you are talking about or it might be a short in the device, I can't tell from the datasheet.



Here's a top view of the converter, and it's single sided, so nothing hidden underneath.
https://i.ebayimg.com/images/g/I0sAA...uu/s-l1600.jpg

If you look at internal circuit of the XL (or any other Buck converter topology), if that MOSFET connected between VIN and SW, it will pass full input Voltage to output.

[sam_sam_sam]

Re: Here is a new twist to using an ATX Power Supply

I wanted have a way to test 18650 batteries charging a phone or tablet and use the battery testing machine that I have to see how long the running time would be

Now I have to work on the back cover for this project

Here is an update ( this is part of the back cover for the other project )

I bought these battery fixtures when I bought the battery tester machine but I did not like the way you have to hang them in mid air I was afraid that the battery would short out so I have not used them

Until the other day when the wheels started turning in my head on how to solve this problem

You will see how I resolved this problem

The 3D printer came to the rescue as you will see in the pictures below I still have more work to do it before it is finished

I will have remove the terminal connector out of the way so that it can move to the end of the travel
With the spacers makes it about two 3 mil meters longer than it was

It took a little while to make the 3D drawings
It was trial and error before I got some working spacer holders for this battery testing fixture

I have basically work on for the last two days ( not all day long but quite a few hours at a time )

I would draw it make a small section of it that I was trying to fit once I got this part done then I would work on the next part I need to fit then I did same thing for the other side but both sides are not the same

One note

The battery only goes into the spacer holder about a mil meter or so just enough to hold the battery in place

I also going to make some spacer holders for the batteries that are the same length but are fatter they have the same problem but not quite as bad

[clearchris]

Re: Here is a new twist to using an ATX Power Supply

Nice. I bet it was pretty quick to design too. 3d printers are great for stuff like this.

[sam_sam_sam]

Re: Here is a new twist to using an ATX Power Supply

Nice. I bet it was pretty quick to design too. 3d printers are great for stuff like this.

I have to tell you that it was not that quick because of fact if you measure exactly it does not fit it a little bit off by a few mm when you are doing hexagon shape I had to add at least 2 mm more so it would fit a little bit loose

The other problem was the space of the nut on the pin holder had to make it so that the hole was with hexagon shape covered with the filament then after the cylinder shape so the battery would fit the battery cylinder shape need to be a few mm more so the battery would fit tightly for the positive side of the battery and the negative side of battery the size need to be a slightly bigger in diameter so battery would slid so that has some room to move

I do not have a problem with outside dimensions they are correct but it is the inside dimensions is the issue for me getting this correct

So my guess is that there is some shrinking going on but I have not quite figured how to determine just how much to to add

The first picture is the positive post the second picture is of the negative post

I will not share the files for this mod right now because I still have to make some small changes it need a little more work when I make the second set it is positive side to make a little longer than what I have right now

One note

each color is to add object and subtraction of an object to create this one object piece

One other note

I going use the negative object to make a 18650 battery holder for my USB project
But I going to modify the size of the size of mounting terminals screws and make a mounting that will be easy to remove and install batteries in it

I am still working on the concept in my head and have not figured out all the details yet

[clearchris]

Re: Here is a new twist to using an ATX Power Supply

In general, for two straight pieces to fit together, I usually add 0.2mm gap, and that works perfectly. Circles get 0.1mm added to the radius or 0.2mm to the diameter. Parts often still require a light finishing, if you don't have a set of small files, buy one. You can buy cheap, it doesn't take much to file plastic, and you don't want really aggressive files either.

https://www.harborfreight.com/12-pie...-set-4614.html
I use mostly the flat files and the round ones. One of these round files is perfect for reaming out 3mm holes.

I also use a few of these for prying out stuck supports, etc.
https://www.harborfreight.com/6-piec...set-34152.html

Both of those together is under $10. Cheaper if you use coupons which are commonly available.

If you don't have a pair of calipers, you really, really need one. Get a metal digital caliper. They don't appear to sell the exact one I have. If you have the budget, get the one that also has fractional imperial readings. I'm always checking the digital to fractional charts, it's annoying.

https://www.harborfreight.com/search?q=calipers

I also use a hot air station to finish parts. It's really good for knocking off any stringing. Any of the cheap and cheesy hot air stations work. $35 or so. Or a hot gun works too, but you need to have a quick hand.

When I design parts, I generally measure multiple items, because variation is expected. Then take the biggest reading, and note it down. Keep your original reading, and add (or subtract) adjustments. In openscad, I'll do things like:

myvar = 12.0 + 0.2;

You want to keep your original measurements seperate from any adjustments if you can. Helps keep you sane when you have to adjust things to fit. I don't know if MS 3d paint supports anything like that though.

For your design, fit doesn't need to be perfect, and probably shouldn't. Batteries can expand, batteries get hot and cold, you need to not put undue pressure on them.

Also, don't underestimate the number of faces and how it affects fit. In openscad and freecad, you can adjust the number of lines/faces that makes up a circle/cylinder, I usually specify at least 200. Your designs look like they use much fewer, maybe 60-80, and that affects fit, more than you would think. The renders take a lot longer, but you end up with IMHO, a better finished product.

In most design software, hexagons are specified by the circum-something (forget the name) but it's the radius of a circle that intersects all the vertices on your shape. Don't forget to add 0.1mm to that.

If it feels like you are drinking from the firehose, it's because you are. There's a bit of a learning curve to this, but once you become proficient, it's very powerful.

[sam_sam_sam]

Re: Here is a new twist to using an ATX Power Supply

In general, for two straight pieces to fit together, I usually add 0.2mm gap, and that works perfectly. Circles get 0.1mm added to the radius or 0.2mm to the diameter. Parts often still require a light finishing, if you don't have a set of small files, buy one. You can buy cheap, it doesn't take much to file plastic, and you don't want really aggressive files either.

https://www.harborfreight.com/12-pie...-set-4614.html
I use mostly the flat files and the round ones. One of these round files is perfect for reaming out 3mm holes.

I also use a few of these for prying out stuck supports, etc.
https://www.harborfreight.com/6-piec...set-34152.html

Both of those together is under $10. Cheaper if you use coupons which are commonly available.

If you don't have a pair of calipers, you really, really need one. Get a metal digital caliper. They don't appear to sell the exact one I have. If you have the budget, get the one that also has fractional imperial readings. I'm always checking the digital to fractional charts, it's annoying.

https://www.harborfreight.com/search?q=calipers

I also use a hot air station to finish parts. It's really good for knocking off any stringing. Any of the cheap and cheesy hot air stations work. $35 or so. Or a hot gun works too, but you need to have a quick hand.

When I design parts, I generally measure multiple items, because variation is expected. Then take the biggest reading, and note it down. Keep your original reading, and add (or subtract) adjustments. In openscad, I'll do things like:

myvar = 12.0 + 0.2;

You want to keep your original measurements seperate from any adjustments if you can. Helps keep you sane when you have to adjust things to fit. I don't know if MS 3d paint supports anything like that though.

For your design, fit doesn't need to be perfect, and probably shouldn't. Batteries can expand, batteries get hot and cold, you need to not put undue pressure on them.

Also, don't underestimate the number of faces and how it affects fit. In openscad and freecad, you can adjust the number of lines/faces that makes up a circle/cylinder, I usually specify at least 200. Your designs look like they use much fewer, maybe 60-80, and that affects fit, more than you would think. The renders take a lot longer, but you end up with IMHO, a better finished product.

In most design software, hexagons are specified by the circum-something (forget the name) but it's the radius of a circle that intersects all the vertices on your shape. Don't forget to add 0.1mm to that.

If it feels like you are drinking from the firehose, it's because you are. There's a bit of a learning curve to this, but once you become proficient, it's very powerful.

Thanks for sharing information


I figured that there would be some shrinkage but still have not completely figured out how much to allow for it but I will figure it out


But I do have a question I want to completely enclose a 18650 battery but how much bigger in diameter should I make to allow for heating and cooling so I can get the battery out of this case

[clearchris]

Re: Here is a new twist to using an ATX Power Supply

I think your fit issues have much less to do with shrinkage, and more to do with the number of faces on your printed circle. Go here and look at the green cylinders.

https://www.rs-online.com/designspar...ting-using-dsm

The leftmost cylinder has the tightest *functional* inner radius because it's the coarsest print. This is true even though the "as designed" radius is the same. Don't underestimate this effect.

Otherwise, you need to print out a 20mm calibration cube and measure it. Then calibrate your axes.

I haven't done any battery cases, so I don't have any direct experience there. I would take a look up on thingiverse first and see what people have done already. You might find one ready to go, or you might see a few that have good ideas you want to incorporate into your own design.

[sam_sam_sam]

Re: Here is a new twist to using an ATX Power Supply

It might be a calibration issue more than anything because it is a perfectly round but just a few millimeters small but the squares come out correctly as far as I know

This happens mostly on inside measurements not outside measurements so I am a little confused about this issue

I would think that if one measurement is all the other measurements would be off

Correct me if I am wrong because I ask the person I bought the printer from the same question and he said that he has same problem with the inside measurements being just a little bit off

I am going to print one of these battery cases and see if this one will work good and go from there

https://www.thingiverse.com/thing:456900/files

[sam_sam_sam]

Re: Here is a new twist to using an ATX Power Supply

Now on a slightly different topic

I just bought me another Ender 3 3D printer and modify ( the one I have been using ) it so it is a laser burner and remove the extruder and hot bed but use the temperature sensor one on the laser housing and the temperature of the cooling fan air

I found some very interesting software to use for this application

But I do not have all the parts to do this modification yet so I have put it on hold for now

I have a laser module but I have to check for it output power
I have to make the laser mounting to where the extruder is
I have to get a buck converter that is rated for more than 3 amps
I have make a enclosure for the power switch and power off LED light for the laser Power OFF
I have to get a welder safety glass shield that is plasma rated for in front of the laser ( this is a maybe )
I have get a red colored laser and a green colored glasses for safety
I have to download the the software to create the g-code and the software for creating the objects

I also found some software for creating circuit board ( in g-code ) which is something I want to be able to do as well