I want a big 5 volt composite video LCD screen!

Post by **benheck** » Fri Sep 17, 2004 5:51 pm

It is for my personal holy grail uber-portable project: the Atari 800 Laptop! Many of you know I'm working on one, now I guess you all do. The ROM/IDE/CompactFlash issue is being resolved, the case and battery is a no-brainer, all that remains is the screen!

It seems anything over 5" diagonal runs off 12 volts. I really want this thing to run off 5 volts with a 7-9 volt battery powering it all. Do any of those 12 volt car ones actually take much less? I need to know, it's driving me nuts!

So, post below or message me. The person who helps will get an Honorable Reference in the Atari 800 Laptop Making Of! (Along with the Atari-to-IDE adapter guy)

Thanks!

Post by **gannon** » Fri Sep 17, 2004 6:09 pm

Just wondering, but what voltage(s) does that computer take?

Also, I hope you find a screen to fit your needs

Post by **benheck** » Sat Sep 18, 2004 12:38 pm

It runs off 5 volts. I used a switching regulator to power it.

mindstein · Post by **mindstein** » Sat Sep 18, 2004 2:44 pm

Hi Ben,
I just found this on ebay
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 08392&rd=1
Please note that although the power supply said
Output: 12VDC, 3.33A (40W) Max
that seems to be for the wall wart.
the batery it comes with is actualy a:
Detachable 8.4V, 4200mAh Ni-MH Battery Pack

So this should work. If you dont like this brand (it is very expensive) I am sure that others will be powered the same way. So I think one can be found.

If this 5.6 inch screen can run off of 8.4v then so should others.

Also have you thought of using a voltage doubler circuit (this might work)
I use this tequnique in some of my robotics to get the result I want. But I usualy only need the higher voltage for a milisecond. I don't know how it would work with a continuous flow of voltage.

ONE MORE THING. Which switching regulator do you use to replace the 7805. I have asked several times and get no responce from you or the forum on this.

I hope this helps.

mindstein · Post by **mindstein** » Sat Sep 18, 2004 2:53 pm

Hi Ben, I just found that Forrest M. Mims III. has several voltage doublers.
Check out the "bridge voltage doubler" you get out 2X Vin.
Or the "cascade voltage doubler"

Large caps should be used to reduce the ripple in the current..

This might work with a 7.2v or 9v doubled and run through a voltage regulator to step it down again. I dont know if this is the solution but I though I would through it out there.

HK-47 · Post by **HK-47** » Sat Sep 18, 2004 3:35 pm

Ben, if i were you I'd figure out a way to make the PSone screen work. There's gotta be a way to do it!

Then you could use your 7.2 volt battery or whatever since the PSone screen uses a 7805!

After all you even said your self a few days ago in the chatroom.

19:17:11 [benheckc] The Atari 2600 signal isn't enough for the 5" PSone screen but I'll amplify it. I'm SURE it'll work

So if you said it will work I'm sure you'll get it working.

Another alterative would be to use a 9 volt screen, then use a 9v batter like this. You could then get a screen like this or something else. (The link says the power input is 9 v but the power consumption is 12v, I bet it has a 7805 or something similar in it!)

Though anyway I say your best bet is the PSone LCD with some Atari compatablity upgrades.

Oh, no!

I just realized the PSone screen wasn't compatible with the 2600's... but the PSone screen is still a good idea right?

Post by **gannon** » Sat Sep 18, 2004 3:44 pm

But Ben said he wanted a screen larger than 5".
I suppose he could use a 12V screen and then use a dc-dc converter for the 5V that the computer needs.

NiN^_^NiN · Post by **NiN^_^NiN** » Sun Sep 19, 2004 2:44 am

I'll have a look at the 7" lcd i have and see what voltage it can run at as its being installed in my car as the carputer LCD hehe

cennar · Post by **cennar** » Sun Sep 19, 2004 3:29 am

oh dude if ben baked for three days strate.. sweet.. oh that reminds me i have more weed.. and im happy that the new PSoneP that youve made looks better than the last one.

Post by **benheck** » Sun Sep 19, 2004 2:20 pm

I want it to be at least 7" diagonal and not widescreen. A PSone screen would look dinky compared to the size of the keyboard.

Post by **SpongeBuell** » Sun Sep 19, 2004 4:10 pm

Hey, you finally have an avatar

NiN^_^NiN|Work · Post by **NiN^_^NiN|Work** » Sun Sep 19, 2004 8:25 pm

I'll check the LCD tonight ben its a non widescreen 7" you would have to make the audio amp tho as the lcd is OEM just a lcd and controller board.

now time for me to hunt for a avatar

HK-47 · Post by **HK-47** » Wed Sep 22, 2004 2:34 pm

I just found this http://store.earthlcd.com/s.nl/c.318770 ... /id.717/.f
it is a computer with a built in screen, but its 10" and runs off 5 volts so I should be able to find something that will be good for you, Ben.

I'll post back in a bit.

HK-47 · Post by **HK-47** » Wed Sep 22, 2004 3:30 pm

Anyway I looked around and I never found anything. But I didn't look around that hard. My only other idea is to power a 12 volt screen with 10 AA batteries.
Besides that I don't know...

NiN^_^NiN · Post by **NiN^_^NiN** » Fri Sep 24, 2004 10:55 am

Well ben Good news

My 7" composite non widescreen LCD works

it says 12v needed at 2amps but thats overrated

i had it in the car witht he PC turned on and it worked at 12v so i changed it to 9v and it work same with 7.5v buthen then i put it as 6v

IT WORKED

i didnt have a 5 v only a 4.5v and the screen worked the the image was really screwed

but 6v works and it prob work great at 5v but u can get away with it at 6v

Now the LCD runs at 500mA ok but it does have a slight annoyence and at 800mA it works smooth u dont notice it on 500mA unless you look for it.

But if you did a LED mod and removed the 30v transformer for the backlight you would be set

The LCD is a 7" Unipac thats all the info i have as its a OEM lcd no sound nothing just the LCD with the controller board glued on the back

Now mine is PAL but im sure that a ntsc version is available as its got stickrs on it saying PAL which leads me to believe there is a NTSC version as i know the 5" unipac has NTSC s there is no reason why not

I hope this has helped your search for a 7" non widescreen

EDIT: its 3am so i hope this is readable