custom/home made gadgets, etc.

[Logistics]

Re: custom/home made gadgets, etc.

LoL! I remember one of the first things I made that had anything even remotely to do with electronics was taking a little alarm-type speaker which... I can't even imagine what it was originally for because it wasn't gigantic, but it wasn't tiny at about 1-1/4", but I hooked it up to the telephone wires in my room and put it in a little, six-inch baseball card box, and stuffed it with poly-fill to make the tone softer. My parents and friends were getting upset that I couldn't hear the phone ring from in my room so this was my solution. Haha!

[c_hegge]

Re: custom/home made gadgets, etc.

Hi Everyone! I made this for cleaning dust out of computers after almost choking on a few when trying to fix overheating problems caused by dust-sealed CPU coolers. It consists of the following:

- A very high RPM fan (in this case a blower removed from a Dell GX270's CPU cooler)
- The neck from a lemonade bottle
- Two fan grills with a layer of foam sandwitched between them
- The bristles from a small brush
- The molex connector from a siezed case fan
- Lots of tape

So far, it has been fairly effective. To clean, I just put the hose from a bigger vacuum cleaner over the top and nearly all of the dust gets sucked out.

[PCBONEZ]

Re: custom/home made gadgets, etc.

If it works, it works!

[chipinnc]

Re: custom/home made gadgets, etc.

The KeriProductions ATX338 Load Tester for ATX Power Supplies.

It provides a convenient set of fan-cooled resistors to load up a PSU while providing voltage readings and scope outputs. The total load is roughly 338 watts which is enough to cause most PSUs to ramp up the fan speed and more than enough to kill a cheap PSU.

It works exactly as intended and is a great help for checking Power Supplies.

The prototype has digital voltmeters. I'm working on an analog version that uses Analog meters and maybe silkscreened markings instead of a stick-on Inkjet label.

It's not too bad for someone that isn't all that great at electronics, is it?

Keri

PS. Thanks to all here for the great advice on how to build and use it, especially Oklahoma Wolf.

PPS. Oh! I once made a special pliers thing out of a pair of Vise Grips. Well, I did have someone weld it for me but it was my idea. No pics though.

How about some more details (schematics / part numbers / etc.) for the KeriProductions ATX338 Load Tester?

[ratdude747]

Re: custom/home made gadgets, etc.

How about some more details (schematics / part numbers / etc.) for the KeriProductions ATX338 Load Tester?

she got chased off the forum when a flame war erupted over operas vs rock concerts.

so i highly doubt you will hear from her.

[MXM]

Re: custom/home made gadgets, etc.

Hi Everyone! I made this for cleaning dust out of computers after almost choking on a few when trying to fix overheating problems caused by dust-sealed CPU coolers. It consists of the following:

- A very high RPM fan (in this case a blower removed from a Dell GX270's CPU cooler)
- The neck from a lemonade bottle
- Two fan grills with a layer of foam sandwitched between them
- The bristles from a small brush
- The molex connector from a siezed case fan
- Lots of tape

So far, it has been fairly effective. To clean, I just put the hose from a bigger vacuum cleaner over the top and nearly all of the dust gets sucked out.

dude home made portable vaccum.... damn, im gonna try it one day, nice work!!

nice thread

[dood]

Re: custom/home made gadgets, etc.

I once put a nail through an old strip of molding to be able to slip down alongside a pontiac grand-am v-6 engine so I could slip the serpentine belt on the bottom idler while holding off the tensioner at the top.

That's about as good as I get.

[Hondaman]

OTA [free networks] television antenna

The Gray-Hoverman TV antenna works well (except for VHF). Smokin' good performance up in the channel 25 to 35 range (digital TV stops around channel 50 or so).



Anyone can take naked copper wire, screw it to a 2-by-4 piece of lumber, attach a 300-ohm to 75-ohm transformer (to connect to modern sets) and lean it against the wall behind a curtain or something. I wanted to do it with PVC, so I got PVC.

The chicken-wire backplane is 4 inches behind the driven elements, faithful to the hobbyists who adapted the Gray-Hoverman design. I decided on a base of 10 inches wide by 8 inches deep, to put on top of my DVR unit. It's something you could sketch out on a cocktail napkin, really (I used notebook paper). Quite fun to see it take shape. After you cut the PVC bits, file them to be PRECISELY the right size and it fits TIGHTLY with no glue. Total size is 35 inches tall, 27 inches wide.

I'm still living in my parents' house -- drilling holes in walls and hooking up another splitter to the rooftop antenna just wasn't an option for me.

[93daytona]

Re: custom/home made gadgets, etc.

Since it seems like this isn't being limited to computer related gadgets, here is the cyclone dust separator I built last summer. A shopvac hose attaches to the top port, and the side port (that enters the cylinder tangentially) the collection hose attaches to.

I'll be making a second revision of it this summer that will be a stand alone unit (no shopvac needed) and will actually use some computer parts



After sucking up some MDF dust:


and this is all the dust that made it through to the shop-vac:

[RJARRRPCGP]

Re: custom/home made gadgets, etc.

Pins of Pain

That immediately reminded me of the socket 775 push-pins. Those were a pain when I first built a socket 775 system in September, 2008.

[shovenose]

Re: custom/home made gadgets, etc.

to start, this is a modified 20 to 20+4 atx adapter. i added an on/off swiche between green and ground, making it so you can test ps voltages/fans/other devices without a motherboard.

obviously, it works with 20+4, but also regular 20 (line up green wires)

did exact smae thing but with duct tape

[kc8adu]

Re: custom/home made gadgets, etc.

digging in the pole barn loft i found one of my homebrew radar jammers.gotta bring it home and take pics.x,k,and ka and you dial your own speed.

[dood]

Re: custom/home made gadgets, etc.

So sad that KeriJane is gone... some of the best homebrewed test equipment there...

[shovenose]

Re: custom/home made gadgets, etc.

Hello! So i was going to make a psu loader, lets call it version 1. I posted tomshardware.com(where i am a forum member). But thwt idea never happened. And im not going to spend several thousand $ on one of those sunmoon things thwt jonnyguru.com uses. I need to build it myself. Help please...tyvm!!!

[shovenose]

Re: custom/home made gadgets, etc.

So lets work on a version 2! Yay

[c_hegge]

Re: custom/home made gadgets, etc.

I'm thinking of diong a similar thing myself.

[Th3_uN1Qu3]

Re: custom/home made gadgets, etc.

A PSU load you say. Easy enough. Big ass MOSFETs, big ass heatsink. You operate the transistors in linear mode, by applying fixed voltage to the gate. The more voltage you apply, the more the gate opens, and the more load is placed onto the PSU. Do use a lot of FETs however (i'd say 10 at the very minimum), coz it's gonna get real hot, real quick.

So that you can check whether the power supply is still operating properly with that load, you're also going to need a multimeter and an oscilloscope. Using some opamps configured the right way you can set up a few LEDs to show the ripple level on each rail so you don't need to constantly move the 'scope probe around to check ripple on the various rails, but you will still need to have an oscilloscope for initial calibration of the LED meter.

Hint: The opamps will need to be quite fast, you need at least 20x gain at up to 1MHz. Basically what you do is wire the opamp inputs to the power supply rail with coupling capacitors in between, so that only ripple gets thru. Then the ripple is amplified by the opamps, and the resulting signal should have enough level to light up an LED if ripple is higher than allowed by the ATX specs. For extra style make a bargraph type of thing, with more LEDs for each rail, so you not only know that the power supply is in spec, but also know how good it is. But this is a bit more complicated than just getting one single LED to light up, so try doing that first.

[kc8adu]

Re: custom/home made gadgets, etc.

this would be a great project.

[shovenose]

Re: custom/home made gadgets, etc.

Ok. But i thought i had to use resistors? Ok well how big do my heatsinks have to be? What kind of mosfet do i need? How do i control the load? How many watts load would it be? Are mosfets expensive? Would i need a cooling fsn?

[Th3_uN1Qu3]

Re: custom/home made gadgets, etc.

Yes, you can use resistors too, but unless you have a lot of different value power resistors (which are also expensive), there is no way of varying the load. With an active circuit such as the one i described you can vary the load from essentialy zero to short circuit. Oh yeah and you'll need a heavy-duty amp meter as well. The cheapo ones won't cut it because their shunts have quite high resistance, and will burn up if you use them continuously.

For the mosfets all you care about is that they should be able to dissipate as much power as possible, and that they have medium to high Rds(on). You're looking in the range of 0.5 - 2ohm Rds(on). With a very low Rds(on) device such as a motherboard mosfet, the gate voltage difference between what looks like a low load to the PSU and what looks like a short circuit would be very small, thus it'll be difficult to control.

Heatsinks... Ever opened up a BIG power amplifier? Like, a professional unit with 1kW power or more? That's about the size of heatsinks you will need. If you use fans, you can get away with smaller heatsinks.

You control the load by applying a variable voltage between gate and source. A simple trimpot is enough to control the voltage, a high current driver is not necessary in linear mode. The necessary voltage source can be derived from the 12v rail of the PSU under test.