Where to get +12v?

[Jzero]

So after a bit of bungling, I made a cute little USB cable to supply the +5v DC to my Matrix Orbital LCD panel.
Only to realize this particular display has the wide-voltage option and uses +8-15v! Grrr.

At this point, it's really only useful if I can get it away from the PC and mount it somewhere else. What are some good ways to get the +12V DC to it?

Thanks for any and all suggestions.

 

[ChampionAtTufshop]

run a line from a molex to the usb cable, so it will send 12v from molex instead of 5v

like you know molex to 3pin converter, buy one (or make one for that matter) and chop off the 3 pin side

 

[panhead49]

one way is to get some sore of 12 volt charger that you would use to charge your electric screw driver or run your speakers off of....you would have to make sure that the amps of the charger you get would work with your display........you dont want to damage it......

 

[Jzero]

Originally posted by: ChampionAtTufshop
run a line from a molex to the usb cable, so it will send 12v from molex instead of 5v

like you know molex to 3pin converter, buy one (or make one for that matter) and chop off the 3 pin side

I'm not sure I follow.
The LCD by default takes a modified floppy drive connector. The difference is the far left pin is +12V and the far right pin is gnd and the middle two pins aren't used (at least not for power).

So my plan was to have USB on one end and the 4-pin floppy on the other.

one way is to get some sore of 12 volt charger that you would use to charge your electric screw driver or run your speakers off of....you would have to make sure that the amps of the charger you get would work with your display........you dont want to damage it......

Rats! I want to do it with stuff I have laying around the house! hehe
Do the amperages have to match? If not, it's safer for the supply to be lower than the draw, right?


I guess last resort is just to make a really long extension from the inside of the PC, but that's hardly elegant....

 

[ChampionAtTufshop]

well you know how you need a usb on one side, and usb only supplies +5v, but molex supplies +12v
so use the +12v from molex to the usb cable (make some sort of make shift cable) to supply the +12v needed
(or if you have a usb header bracket thing, maybe rig up a molex to supply +12v to it instead of the +5v it would draw from mobo header...if it doesnt fry the usb header it should work lol)

the cablecould be quite long, so you could tuck it away somewhere in your case too if needed

 

[Jzero]

Originally posted by: ChampionAtTufshop
well you know how you need a usb on one side, and usb only supplies +5v, but molex supplies +12v
so use the +12v from molex to the usb cable (make some sort of make shift cable) to supply the +12v needed
(or if you have a usb header bracket thing, maybe rig up a molex to supply +12v to it instead of the +5v it would draw from mobo header...if it doesnt fry the usb header it should work lol)

the cablecould be quite long, so you could tuck it away somewhere in your case too if needed

I think I see what you're saying. Although at that point since I'd still have to draw the power from inside the case, I may as well just dump the USB cable and just run some log wires out from one of the molex connectors.

I was planning on plugging it into my USB hub so I could pretty much power it from anywhere without having to work a wire out through the case and have it always be tethered to the PC.

 

[ChampionAtTufshop]

maybe create a little housing for it
and stick in a matx psu?

 

[Jzero]

Originally posted by: ChampionAtTufshop
maybe create a little housing for it
and stick in a matx psu?

Yes a housing is a very good idea and I think I'll look into that.
The only problem with using an matx PSU is that it seems like an awful lot of overkill for something that at MOST (backlight on) uses less than 2W and without the backlight on uses more like .1W 🙂 I'd be wasting a lot of electricity for a novelty.

 

[ChampionAtTufshop]

Originally posted by: Jzero

Originally posted by: ChampionAtTufshop
maybe create a little housing for it
and stick in a matx psu?

Yes a housing is a very good idea and I think I'll look into that.
The only problem with using an matx PSU is that it seems like an awful lot of overkill for something that at MOST (backlight on) uses less than 2W and without the backlight on uses more like .1W 🙂 I'd be wasting a lot of electricity for a novelty.

or maybe an DC to AC inverter lol
house that in the housing

i dont nokw however if and DC inverters supply +12v off the top of my head

 

[Jzero]

Originally posted by: ChampionAtTufshop

Originally posted by: Jzero

Originally posted by: ChampionAtTufshop
maybe create a little housing for it
and stick in a matx psu?

Yes a housing is a very good idea and I think I'll look into that.
The only problem with using an matx PSU is that it seems like an awful lot of overkill for something that at MOST (backlight on) uses less than 2W and without the backlight on uses more like .1W 🙂 I'd be wasting a lot of electricity for a novelty.

or maybe an DC to AC inverter lol
house that in the housing

i dont nokw however if and DC inverters supply +12v off the top of my head

Well, there's not really any reason I couldn't use an AC adapter. In fact, now that I'm thinking of it, I have a 12V adapter from something else. Only question in my mind is that it's 500mA while the LCD is 115mA. I can't remember if it's bad to supply more current than is drawn, or if it's bad to draw more current than is supplied.

 

[ChampionAtTufshop]

well im not 100% sure
but it seems supplying more current would be worse than drawing more current

although both could be bad...

supplying mroe than is drawn could overcurrent (for the lack of a better word heh) the device
drawing more current than needed could be harmful to the adaptor

 

[Jzero]

Bump...
Next question as above.

Is it safe to use a 12V 500mA AC adapter when the unit is spec'ed to draw 115mA?
Thanks and thanks to the Champ for your suggestions last night.

 

[RSMemphis]

Yes, it's always better to be able to offer more than is demanded.

Your LCD won't draw more than 115 mA... Even if you supply 2A or more. It will always only draw 115 mA.

The voltage has to match though, if you supply 24V, your device will draw 230 mA, and will burn rather quickly. 🙂

 

[Jzero]

Originally posted by: RSMemphis
Yes, it's always better to be able to offer more than is demanded.

Your LCD won't draw more than 115 mA... Even if you supply 2A or more. It will always only draw 115 mA.

The voltage has to match though, if you supply 24V, your device will draw 230 mA, and will burn rather quickly. 🙂

That's what I thought, but I couldn't remember for sure.
The adapter can supply up to 500mA if what is using it happens to draw that much, but no more current is drawn than the LCD needs.
The voltage on the adapter is definitely 12V. It's just a garden-variety Radio Shack universal adapter I picked up for another device that I don't use anymore.

Thanks!

 

[ChampionAtTufshop]

remember to post pics somewhere when you are done 😀

 

[Jzero]

Originally posted by: ChampionAtTufshop
remember to post pics somewhere when you are done 😀

You got it. It's not gonna be pretty at first 🙂

Here's a fun anecdote:
For a project I once had to write a client/server app. The class was an application server tech class.
I had this LCD mounted in a 5.25" bay in my PC.
Most of the class just did some EJB database demos.

I made a quickie VB server that listened for a TCP connection, accepted a buffer, opened the serial port and dumped that data onto the LCD.
Then an even quicker VB client that called the server and gave it the data.

For my in-class demo, I ran the server on my PC, brought the client on a disk, pointed my webcam at the LCD.
Brought up the webcam view, and then sent text to the LCD and watched it change on the webcam 🙂

It was great.

 

[ChampionAtTufshop]

wow
...that makes me want to learn programming one of these days if i can find the time

what are some "good" (good meaning useful for cool things, such as what you described) languages to start learning?

//edit
also does being A+ certified hold any value for someone looking to go into electrical engineering or computer engineering?

 

[Jzero]

Originally posted by: ChampionAtTufshop
wow
...that makes me want to learn programming one of these days if i can find the time

what are some "good" (good meaning useful for cool things, such as what you described) languages to start learning?

//edit
also does being A+ certified hold any value for someone looking to go into electrical engineering or computer engineering?

I usually use Java or Visual Basic. They may not be as fast or full-featured as other languages, but they are fairly simple and for someone like me who isn't writing production code but is really just writing quick fun utilities for peronal use, they are perfect. For the project I described above, as a matter of fact, I used VB simply b/c I didn't want to take the time to figure out how to open a COM port in Java 🙂

I'm not sure if A+ would do much for you becoming an EE or Comp Engineer. Those disciplines go pretty in-depth in terms of math, and even the chemistry behind electronics.


Anyway, just wanted to provide an update--I tried to use that 12v adaptor and for some reason I couldn't get it to work. I tested it with my meter and it was actually putting a little over 15v out and since the device tops out at 15v, perhpas it has something in it to prevent it from running if the voltage is too high? I considered cutting the end off and splicing the wires directly but I felt bad ruining a perfectly good adapter for something that is cool but not very important.

So, I simply spliced 4 feet of wire in between the molex connectors and I guess for the time being I'll run it into my PC through a slot cover. Que Sera.
Now to devise an enclosure. I'll keep you posted.

Thanks everyone for your help.