I have 2 lcd's and I am confused,

[jjandrj6679]

Hi there.
Firstly, as I am a newbie to this field, I bow to your expert knowledge, I undestand the basics, but I am now confused as to which way to go.
I am near the end of the design stage of my rig. I have purchaced two LCD's, these are 2x40 LM018L & 2x24 Red HD44780.
The 2x40 was for experamenting.
The 2x24 Red one is so hard to find and my project was orange and red.

But I have, since reading this forum, discovered many differant ways and theories as to the wiring them up. So I am confused.

Even more now since I have looked at the back of the 2x24 Red one, not only are there 14 odd resistors and a couple of capasitors there seems to be a potentiometer as well.????
I have pictures
http://img186.imageshack.us/my.php?imag ... redqz9.jpg
http://img186.imageshack.us/my.php?imag ... 422ru9.jpg

So what I would like to do is get the Red 2x24 up and running in my main Rig via Parallel with a pci parallel card.
I would like to be able to us a pot to set the brightness of the backlight
I would like to be able to us a pot to set the contrast
I would like to be able to show temps and cpu/gpu freq

The 2x40 in my day to day pc which has an Asetek Extreme pump in it, which has its own 16 pin arrangement. I would like to be able to show the stuff on the pump.
I think I should have done this in two differant posts.

here is the data I have for the for the Red LCD

1. 5x8 dots inc cursor
2. Built in controler HD44780 or Equivalent
3. +5v Power Supply
4. 1/16 duty cycle
5. LED can be driven by pin 15 & pin 16 or A & K

Pin Symble Function
1 Vss Ground
2 Vdd +5v
3 V0 Contrast Adj
4 Rs H/L Register select signal
5 R/W H/L Read/Write Signal
6 E H -> L Enable Signal
7 DB0 H/L Data Bus Line
8 DB1 H/L Data Bus Line
9 DB2 H/L Data Bus Line
10 DB3 H/L Data Bus Line
11 DB4 H/L Data Bus Line
12 DB5 H/L Data Bus Line
13 DB6 H/L Data Bus Line
14 DB7 H/L Data Bus Line
15 A + 4.2v for LED (RA= ) Ohms
16 K Power Supply for B/L (0v)

Power supply VDD - Vss = -0.3(min) & 7.0(max)
Input Voltage VI = -0.3(min) & VDD(max)

Input Voltage VDD = +5v = 4.7v(min) 5.0v(typ) 5.3v(max)
Input Voltage VDD = +3v = 2.7v(min) 3.0v(typ) 5.3v(max)
Supply Current VDD = 5v = --- (min) 0.8ma(typ) 1.1ma(max)
Recomended LC Driving -20c 5.1v(min) 4.9v(typ) 5.7v(max)
Voltage at Normal Temp 0c 4.6v(min) 4.5v(typ) 5.2v(max)
Version Modle +25c 4.1v(min) 4.2v(typ) 4.5v(max)
LED Forward Voltage VF@+25c --- (min) 4.2v(typ) 4.6v(max)
LED Forward Current VI@+25c --- (min) 2.0ma(typ) 4.0ma(max)

HD44780 16 pins with backlight
The only chip on it that I can read is SC17661M UD44BA231 E
All the rest are coverd by black poo

Right I hope that is usefull to you as this is all it has.

What I need to know is this.
Has my lcd modual already got an adjustable pot in it already?
Is it pre resistored, if you know what I mean?
Why is it so differant from those that are on this forum.
How do I wire it up for :-
Manual Brightnes control?
Manual Contrast Control?

Any help would realy be greafully recieved.
Yours
Josh





2x40 LM018L 97-44228-7 Hitachi 14 pins & no backlight.
Its chips are 4 of HD44100FS & 1 of HD44780A00
&
2x24 Red HD44780 16 pins with backlight
The only chip on it that I can read is SC17661M UD44BA231 E
All the rest are coverd by black poo

[Abi_J]

Both displays you have are fine to use, pinouts are the same as most other displays, the wiring is this...

the 10K pot is contrast control, the 100 Ohm is backlight - I would be careful with the backlight control, as wound fully up there is minimal resistance through the pot, and your backlight may not have a limiting resistor fitted to the board, check any datasheet(s) you can find for you particular displays.

You may have noticed that the 2x40 only has 14 pins!? there are 2 pads on the opposite end of the board, they are the backlight terminals.

So far as getting data regarding the pump on your machine, that depends on software, of which AFIK there are only 2 plugins (1 comes with LCDS) that can show system data, one through MBM, one through Everest, if either of them can display the stats you are after, no problem, hoever I think you may not find good news on that score, you will probably hae to submit a plugin request (fieerent forum on here) or code a plugin yourself.

Hope this helps,
Abi.

Edit: I just noticed that you quoted specs for the red display, backlight 4.2v, 2.0Ma, in which case a 470Ohm (yellow, violet, brown) 1/8W or greater would be required, otherwise the pot being wound fully open would over-voltage the LED (stated max 4.6v). Also noticed (I really should read more carefully) that the 4x20 does not have a backlight, therefore you can ignore the comment above about the 2 pads on the one end of the board).

OK, one last note, for a red display you could always buy an RGB display (I have one, depending on my mood I can switch colors - my fans have RGB LEDs in them too).

[jjandrj6679]

Hi there,
Thanks for answering so quick.
That was the diagram that I saw first. It went down hill from there.
Ok firstly I have little experience with pots. So in advance I am sorry if I sound dence, I just don't want to blow the thing up.

I already have http://www.rapidonline.com/Electronic-C ... 222/kw/470
A 10KΩ (Item no 65-0715) one for the contrast which I connect the middle leg to LCD Pin 3 Vlc/Vo, but:-
Which Pot leg goes to LCD +5v Pin 2 Vcc/Vdd & Pin 15 VB+/A ?
Which Pot leg goes to LCD GRND LCD Pin 1 Vss/Vss ?

Ok Now onto the 100Ω
You said

Edit: I just noticed that you quoted specs for the red display, backlight 4.2v, 2.0Ma, in which case a 470Ohm (yellow, violet, brown) 1/8W or greater would be required, otherwise the pot being wound fully open would over-voltage the LED (stated max 4.6v).

Do you mean put a 470Ω Resistor in Parallel/Series to the 100Ω Pot?
Can I put a 470Ω Pot there instead ? (Item No 65-0700)
Could you explain how I wire up the resistor/pot, leg by leg
Also a 1/8w ? do you mean
http://www.rapidonline.com/Electronic-C ... 32/kw/1/8W
PK 100 470R 0.4W MF RESISTOR (RC) Item number 62-2582 ?
If so how is it wired in?
Again many apologies for being a bit thick.
So basicaly what I am trying to ask is:- How do I wire the 100Ω/470Ω Pot & the 470Ω Resistor in ?

One last thing while I am here, is it possible to wire in buttons/switchs to turn it off and to reset the display, or am I way out of my depth there ?

As for the 2x40 green display, I said it had no backlight only because the 2 contacts at the end dont seem to go anywhere, I put my multmeter on them and tryed all of the connections inc earth , but I got nothing, so I assum theres no backlight.

Finaly where can I find RGB displays, had a look at ebay, nothing, googled but didn't come up with much if anything at all.
Thanks again
Josh

[Abi_J]

Ok, pots...

Contrast, 10K, the pot should have 3 pins/legs - if you use regular pots (the kind with the stick to turn) then they should all be in a row, if you use a trim pot (little pot that you use a screwdriver to adjust, they are used for set and forget applications, when you don't need to keep adjusting the setting) then there will be 2 pins on one side, and 1 on the other, the lonely pin is the center pin, the 2 others are the ends.

The center (wiper) pin connects to terminal 3 on the display, the other 2 pins connect to ground/eath and V (power). if when you turn the pot, it works backwards (turn clockwise and the contrast fades), swap the outder pins around.

Backlight,
The 100Ohm pot shows the wiper pin connected to ground as well as 1 end pin, so join 1 end and the center pin together, and to ground/earth. The other pin goes to terminal 16.

for the backlight regulating diode, it should be fitted in series with the pot, so between the pot and terminal 16.

If you still want more info about wiring the pots, let me know and I'll draw up a pictoral for you.

Now, did you test the display with the multimeter connected both ways? most backlights use LED, light emmiting DIODEs, current only passes through them one way, might have had the terminals backwards, there should be markings on the board with A and K, A is terminal 15, K is 16. Easiest way to test is to get a 3v battery (2xAA works) and apply power through those pins, if the display doesn't light, either there is no backlight or it is blown.

RGB backlighted displays are not the most common thing to find, I don't know where you are located (you haven't edited your profile) so I can't offer specific places for your region, I got my displays (currently a blue/white 2x16, an RGB/white 2x16 and a RGB 4x40) from Mouser (www.mouser.com), they are not especially cheap, I think the RGB 2x16 was about $14, the blue/white 2x16 around $11, plus shipping on top of that, but I use mouser for a lot of my components (I have an account with them). You don't need to be a business, or have an account, not to sure about minimum orders though, lowest order I've ever had was around $30.

If, like me you are in the States, you can also look at digikey.com, and farnell.com

Hope this helps,
Abi.

[jjandrj6679]

Hi All
I have managed to track down the spec sheet for my red lcd 2x24, there is a pdf on the page, it may help you guys help me figure it all out
http://www.sureelectronics.net/goods.php?id=130
I look forward to hearing from you soon.
& thanks again for your help so far
Josh

[Abi_J]

Again I didn't answer all your questions from before, my applolgies.

The 470 Ohm 1/8w is capable of withstanding loads up to 1/8th of a watt, you can use any 470Ohm resistor you can get (most of my components like resistors are salvaged from old tv,s stereo's etc.).

For buttons, you can also add up to 16 buttons (with lots of diodes and a simple but awkward circuit - awkwards if you try to fit it onto a small circuit board, gets fiddly) or 4 buttons very easily, if you want lights (status, show when winamp is playing for example) you will need to use an avaliable serial (COM) port, link to the forum post for buttons/lights here...

http://forums.lcdsmartie.org/viewtopic. ... pt+buttons I used the 16 button schematic (28 diodes) long before I ever used LCDS, I had a button rack controlling winamp through a differen program - button rack came from the front of an old vcr and fitted perfectly onto my desk, then I built an IR reciever so the swich rack is waiting for a rebuild for LCDS, I'll post some pics when I find my camera. (Edit: couldn't find my digi cam, so I used the webcam instead... http://www.lamoillecomputerservices.com/compy/).

According to the datasheet from Sure, the LED driving voltage is actually 5v, 5.3v max which means you can omit the 470Ohm resistor, which is safe if you are driving the circuit from the PC power supply, as the 5v line is regulated so it should not get to the 5.3v max (if you use a wallwart plugin, then make sure it is a regulated supply, unregulated supplies could easily go higer than 5.3v).

[Abi_J]

I just got bored so I've uploaded (another, there's loads on the web) lpt port wiring schematic, with pots for contrast and backlight, also current limiting resistor for backlight here...

(http://www.lamoillecomputerservices.com ... pt_lcd.jpg)
Enjoy,
Abi.

[jjandrj6679]

Hi Abi_j
I dont know how to thank you enough, for the effort that you have put into this.
That last diagram said it all, so all I have to do is put a 470Ω Resistor in place of R1 and we are away.
Athough you seem to say that I dont need it later on in your post, shall I just include it to be on the safe side?
As you can see from the back of my screen there is a Pot, any chance you know what it does?

For buttons, you can also add up to 16 buttons (with lots of diodes and a simple but awkward circuit - awkwards if you try to fit it onto a small circuit board, gets fiddly) or 4 buttons very easily, if you want lights (status, show when winamp is playing for example) you will need to use an avaliable serial (COM) port, link to the forum post for buttons/lights here...

To be totaly honest the forum link lost me completely, sorry,
Why would you need 16 buttons? I can think of 4 button max (Forward, back, off/on & reset) but I am sure there is a reason.
My board doesnt have parallel so I had to buy one, now theres a mention of a serial port, I aint got one of those either, grrr I am going backwards to come forwards. lol...
So if you can get bored enough to adjust the schematic that you posted with the appropriate connections for the switches, would be much appreciated by me please.
Wow you use the buttons from a vcr to control winamp. And I thought I was fairly savvey when it came to this kind of stuff. Very impressed, how? please tell all

l test it with 3v tonight when I am there see what happens.
I gotta say that you desk is tidy compared to mine. I usually can't find the ashtray nor the lighter, perhaps there should be a post started for members desks pics..lol

As to what part of the globe I'm from, it the good old isle of the UK, where the rich get richer and the poor get poorer. Dont talk about the tax, gggrrrr ?1.20, per liter grrrr. I was saving up for a 69 fastback, but by the time I restore it, it'll probably be a ?5.00 pl so I need to escape.

Any hows
Looking forward to you next post.
Josh

[Abi_J]

Appologies for the delay in replying, ate too much chocolate earlier and crashed out watching a movie.

The restistor R1...
If the datasheet from Sure Electronics on the web page you gave is indeed for your display, then since it quotes backlight supply voltage (typical) as 5v, the resistor won't be required as the display has a resistor fitted on the board already.

As for the trim pot on the back of the display, looking at the pic I cannot trace the connections back far so I would honestly leave it well alone.

The serial port is only required if you would like to have some (4) LED status lights, lights that you can turn on/off, or can be turned on/off with actions throught LCDS, I would personally not bother since you would be adding a serial port card to your computer just for 4 little lights - I don't have any on my computer sine I use the serial port I have for my infra red sensor (nice to be sat in the lazy chair watching a dvd on the computer using a remote control).

The vcr controls I used to use for winamp used the schematic from the other post, the one with lots of diodes shown, it's a simple circuit, just awkward to make if you are trying to fit it onto a small peice of breadboard. The circuit I used ran on the serial port, using a program called ComCtrl (I think, been a while since I had that setup). A quick rundown of the buttons is...
Power (winamp start/close), Skip F, Skip R, Play, Pause, Stop, Scan F, Scan B, End with fade, End after track, Vol +, Vol -, Open/close visualisation, and then I had a couple of spare buttons that got assigned to open other programs.

As far as my desk,the part by the mouse reciever in the pic is the tidiest part of the desk, to my left, my ashtray is swimming in a pile of electronic components, diodes, capacitors, bits of wire etc., to my right, my mouse has pushed a clearing into the pile of screwdrivers, cutters, reams of solder and various other bits and pieces (of junk mostly), I have to back my chair away from the desk at an angle so I don't crunch a bunch of circuit boards from old tv's, setreo's, computer monitors etc.

If I need a pen that works - all the ones found easily don't work, I have to dig through the filing cabinet under the desk, which is piled up with graphics cards, modems, network cards, sound cards, pc power supplies, memory sticks and pretty much anything else you can ind inside a computer, my digital camera is buried somewhere in this room, I have no idea where though!

As far as tax in England, I'm originally from Daventry, Northants, I now live about 2 hours east of Chicago, I know how you feel about the price of everything, I must admit, over the last 5 years that I've lived here, I must have become "Americanized", I drive a 4.9L pick up that gets 20mpg (damned good for a truck), and even I'm beginning to complain at the $3.30/gallon (U.S., not imperial), I know it'd drive me insane if I had to move back to England and live with paying the same for a litre! I just can't wait until the morning, I get the cast removed from my leg (thats my current excuse for sitting in front of the computer all day/night) so I can then take the motorbike out for a ride tomorrow, I've missed about a weeks worth of decent weather recently because of this chunk of plaster. At least at 45mpg, the bike will stop me whining about fuel prices for a while.

I've added the buttons to the diagram I posted, here it is in all it's splendor...

(http://www.lamoillecomputerservices.com ... uttons.jpg

Note, you will have to use the plugin for LCDS from the other post to get the buttons to control anything, read the documents that come with the plugin for details on how to write the code in LCDS.

Hope you get it working how you want it,
Abi.

[jjandrj6679]

Hi Abi,
I gotta say thank you again for the effort that you have put into my project..
I have just spent the evening designing the board & its done my head in.
Your design looks simple enough, but translateing it to a board is another story.
I am trying to make it that all parts are removable. So the Parallel cable can be removed from the LCD, which would have the wires attached for the pots and switches. At that end there has to be a connector for that board, if you see what I mean....
I'll let you know how I get on tomorrow.
If you have any more ideas/pointer/drawings, they would be warmly welcomed.
So go on, whats the bike, mine was, before the divorce, a Kwak 900R turbo. I put it on myself when I owned an Italian garage.
& how did you break your leg?
Why leave this wounderful labour run hell hole then??? How did you manage to escape?
Josh

[jjandrj6679]

Would a ribbon cable that I am using (Normal Parallel flat ribbon) be able to handle the Volts & amps from the +5v?
Or would I have to put in separate power cables?
Josh

[Abi_J]

Ok, important stuff first...

The bike is a '81 Yammi XJ750R Seca, with genuine 19'000 on the clocks, previous/original owner rode about a mile a day to/from work, then maybe 500 miles a couple of times a year touring.

The leg was from my last blast on the snowmobile, skidoo 650, now missing a ski - front shock exploded and sent me into a tree.

Now for the display stuff...

To fit everything onto a board is no real problem, I have mine built onto a board about 1" x 3/4", I used trim pots since I don't really need to adjust the contrast and backlight, I also fitted a transistor to turn the backlight on/off through LCDS/IR remote. Note, if you are using regular pots (not trimpots) then you do not need to use a board at all...

Most people I know use a regular printer cable, with the printer end chopped off, you fit a 16x1 row of header pins (like the pins your power button, hdd light wires etc. connect to on the motherboard, and a 1x16 header socket (the connector on the power button wires etc.) on the printer cable, that way the cable can be removed from the display easily. The pots simply connect to the wiring, between the printer cable and the connector. Most printer cables have enough wires inside to connect the screen with several spare, use a couple of the remaining wires as 5v power and ground, but remember, open up the connector on the other end of the cable (easier if you buy the cables with the hard plastic snap together case, not the moulded plastic ones) and disconnect the wires you've used for power/ground and connect a molex connector to them.

For parts, I cannot for the life of me remember my old parts suppliers from the UK, excpet for Maplins, I know they are not the cheapest, but they should have anything you require. If you struggle to find parts, let me know and I'll dig up some part numbers and places to get them.

On my computer, I used a regular printer cable inside the computer, one end on the display, the other runs to the back of the case where there is a DB25 (parallel port) connector mounted, facing inside on a spare expansion port blanking plate, on the outside there is a short section of the same cable, running from the blanking plate to the printer port, no wires poking through holes in the back, everything nice and tidy.

Like I said, I have my pots on a tiny board and honestly, I could have left the backlight one off, since the backlight on full bright looks pretty good on my display, I am able to turn the display backlight on/off through a hotkey I have assigned in LCDS (and by assigning a button on my remote to do that hoykey combo), however... I fitted a resistor in parallel to the transistor, so even if the backlight is turned off in LCDS, the actual display is still lit very dimly, otherwise I can hardly read anything on the display. I mainly turn the backlight off/down when watching movies, so I don't have a big blue rectangle in the corner of my eye.

If you want to control the backlight through LCDS (mine flashes the backlight 5 times when I get a new email come through, comes in handy!!), let me know and I'll modify the diagram again to add that function, it adds a transistor and another resistor.

No need to thank me for helping, I'd like to think if I needed some help with something, someone else would do what they can to help (besides, it's 2 am, and my leg is itching like crazy so I can't sleep, might as well get something good out of my sleepless night!).

So far as how/why I escaped the lovely little island, my other half is a yank, so I got a ring on my finger and a green card.

Oh, and for the ribbon cable, it should cope fine, depending on how big/small the individual wires are, I'd maybe use 2 wires for the 5v and ground, the rest should be fine running through single wires in the ribbon.

Have fun wiring,
Abi.

[Abi_J]

here's a post on a different site that shows what I mean regarding the printer cable/power...

http://www.icehw.net/article.php?id=104

Abi.

[jjandrj6679]

Hi Abi
Sorry for the silence, had family matters to deal with.
Ok where are we, I have now made the board with two pots & four switches.
What I have been trying to do is reduce the amount of cabling. You see, my Rig (when its finished) will be made out of clear lexan and accomodate two cooling loops, a shared inbuilt reservior, as it is open plan, the less showing the better.

So I have used a 25 pin flat cable that funnilly enough will lay flat?? the ones that are spare are as follows, 4 for the switches, ther rest for a return of lcd pins1,2,3,15,16 & + & -, meaning that there is one flat cable from the lcd to the Parallel connector.
In that cable is all the wires from said connector and the ones from the lcd, leading to another connector for the switch/pot board. A molex connector will power the board and the lcd via the parallel connector. i hope that all made sence??
I will hopefully have it all soldered up by monday night, tuesday at the latest.
I did loads of diagrams and working outs and here is what I came up with:-

ParallelRibbon End _____ LCDRibbon End _____ Switchboard

Join Cable 24<---------Cable 1<---------LCD Pin 2

Parallel 18>25<---------Cable 2<---------LCD Pin 1 ------->Switchboard------->Earth------->Button 1,2,3,4------->10kpot3------->100pot2,3------->Molex-

Parallel Pin 16 <---------Cable 3 <--------- LCD Pin 4 XXXXX

Join Cable 23 <---------Cable 4 <--------- LCD Pin 3

Parallel Pin 1 <---------Cable 5 <--------- LCD Pin 6 XXXXX

Parallel Pin 14 <---------Cable 6 <--------- LCD Pin 5 XXXXX

Parallel Pin 3 <---------Cable 7 <--------- LCD Pin 8 XXXXX

Parallel Pin 2 <---------Cable 8 <--------- LCD Pin 7 XXXXX

Parallel Pin 5 <---------Cable 9 <--------- LCD Pin 10 XXXXX

Parallel Pin 4 <---------Cable 10 <--------- LCD Pin 9 XXXXX

Parallel Pin 7 <---------Cable 11 <--------- LCD Pin 12 XXXXX

Parallel Pin 6 <---------Cable 12 <---------LCD Pin 11 XXXXX

Parallel Pin 9 <---------Cable 13 <--------- LCD Pin 14 XXXXX

Parallel Pin 8 <---------Cable 14 <--------- LCD Pin 13 XXXXX

Join Cable 21 <---------Cable 15 <--------- LCD Pin 16 ------->Switchboard EARTH------->100pot p1

Join Cable 22 <---------Cable 16 <--------- LCD Pin 15 ------->Switchboard LIVE------->10kpot p1------->Molex+------->(LCD Pin 2)

Parallel Pin 10 --------->Cable 17 ---------> Switchboard------->Switchboard Button 1 Live

Parallel Pin 11 --------->Cable 18 --------->Switchboard------->Switchboard Button 2 Live

Parallel Pin 12 --------->Cable 19 --------->Switchboard------->Switchboard Button 3 Live

Parallel Pin 13 --------->Cable 20 ---------> Switchboard------->Switchboard Button 4 Live

Join Cable 15 --------->Cable 21 ---------> Switchboard-------> EARTH------->100pot p1

Join Cable 16 --------->Cable 22 --------->Switchboard-------> LIVE------->10kpot p1------->Molex+------->(LCD Pin 2)

Join Cable 4 --------->Cable 23 --------->Switchboard------->10kpot 2 Middle

Join Cable 1 --------->Cable 24 ---------> Switchboard------->LIVE------->10kpot p1------->Molex+------->(LCD Pin 15)

<---------Cable 25 --------->


What do you think, it allows you to have one neat cable, a parallel connector one end and two connectors, the other, no messy cables to re-route.
Let me know if I am comnpletely insane, and yes I will post pics of the Rig when its finished.

Yours
Josh
PS how to I put a pic on here like you do, cant figure it out??? Jj

[Abi_J]

Sounds like it's gonna be a sweet looking case when your done, I'm late in replying here too, building another computer system (waiting on a 1TB hdd to setup, just got my old dead mobo (died about a month ago, ended up replacing a full size board with a micro atx for a while) working again, so I have enough spares in my little stash to build another system for myself (also spent several hours cruising on the bike, i can walk normally again!!!).

From what I could decypher of your layout, everything seems to be good.

For images, I post my pics to my (well, company) website, then use the Img code tags above the text box when writing a post, you can attach images as files, but I think you have to have a minimum number of posts before you can. Easiest way is to create an account (free) with imageshack, when you upload pics you can even select the BB code in imageshack so you can just paste it in here, no need to use the Img tags.

Abi.

[jjandrj6679]

I've decided to go with trim pots instead, me feels that once these are set I wont need to twiddle them, and I can always turn the backlibht off,, cant I???
JJ

[Abi_J]

For turning the backlight off, you can either fit a switch in the line (in series to the pot), or you can add a transistor and resistor, so you can switch the backlight off through LCDS.

I fitted the transistor to mine, but with a mod, I added a trimpot in parallel, so when I turn the backlight off, I'm actually turning it down, as the pot still lights the backlight very dimly (otherwise my display is too dark).

I'll mod the schematic again to add the transistor backlight control shortly, I'm bouncing betwwen a bunch of computers right now, installing/configuring programs.

I guess I could also fire up my soldering iron and build another display setup, I've got a spare 2x16 to add to my newest system build.

Abi.

[Abi_J]

Ok, latest incarnation of the layout below.

The transistor is any small NPN signal transistor, the connections will vary depending on the actual transistor used, the schematic shows pins 1,2,3 as BCE, check the datasheet or packaging for the transistor you use.

As posted above, I have a trimpot (I used a 10K since it was the first one I saw lying on my desk) in parallel to the transistor - connected to C and E, so that my backlight turns down, not completely off.


http://www.lamoillecomputerservices.com ... _trans.jpg

This schematic gives control of the backlight through LCDS, and retains the pot for adjusting backlight level.

Abi.

Abi.

[jjandrj6679]

Hi
Ok I got the parallel connector wired up.
I got some 10k trim pots on order, should be here in a couple of days.
S I have to add the 10k pot so that the back light stays on dimmly to what ever I set it at? Yes
What family of NPN's shoould I use? I go to www.rapidonline.com, here in colchester to get most of my stuff, if I am lazy or not got the time I go to ebay???
If you could either give me a couple of modle/types of Transistor, or even better direct me to the apprpriate pages on rapid, that would save me tonnes.
Gotta go to bet for and 8am start.
Again thanks for everything you have done so far and the help to come.
Truley amazed
Yours
Josh

[mattcro]

Based on the pictures and datasheet (DE-LM010.pdf on Sure Electronics) for the 2x24 module, you don't need any extra resistor in series with the 100ohm (NOT 10K ohms!) variable resistor. This LCD module has built in resistors for LED operation from 5V, so a direct connection to the 5V supply will give full brightness, and you can use the 100ohm variable resistor to throttle the brightness back. In LCDs with no built-in resistor, something like 10ohms is usually about right for restricting the max current to a safe level for 5V supply.

For the backlight control transistor, you can use any small NPN bipolar transistor with a current rating of 200mA or more (the LCD backlight draws about 150mA) and high gain (large hFE) - look at BC238B, and even better is a darlington (high gain) transistor like BC517 - both only pennies. The choice isn't too critical though.

I wonder if the LCD includes the contrast potentiometer on the module - that could be what the small trimmer marked R14 is, so try using the module with nothing connected to pin 3 (Vo) and twiddle the pot to see if the contrast is affected. I could be wrong, so make sure you note the position of the pot before twiddling.

As for uploading photos, I use photobucket.com - just sign up and you can upload photos in whatever size you want, and easily link to them in forums like this one. I find imageshack.us is usually quite slow.

[jjandrj6679]

thanks to both of you for your help.
Off to rapidonline in the morning with a long list of things to get.
just a point right next to that weeny trimmer pot is two connectors,
VDD being +5v
&
Vo being contrast adjustment
Any use to me???
I'll let you all know tommorrow evening.

Off to bed and thanks again. JJ

[Abi_J]

Hi, sorry for the lateness of my reply, I've been working out some rough plans for a 2-wheel road trip.

The 10K pot I used for the backlight was picked purely because I had one sat on my desk right by the soldering iron, it is way too high a value really, it only makes a difference to the brightness through about 20? of travel, if that, but since it's a set and forget component, I was not to worried about fine control.

As Mattcro said, the trimpot on the display may be for the contrast, I'm no expert when it comes to displays (or electronics in general, I just like to tinker lots) so I did not want to advise you to adjust it, but if you can follow the tracks from the pot back to any of the connection pads then it would be reasonable easy to figure what it is for.

hope you get the display setup as you want it, and don't forget the pics!

Abi.

[jjandrj6679]

Hi there
just waiting on a tonne of parts from www.rapidonline.com based here in colchester, who just by chance were having a kind of sale on absolutly everything, so I got as much as I could think of and more. most was half price. Its worth a look but its only on till noon.
So I'll pick it all up in the morning and have a bash at finishing it off over the weekend.
Till then have a good end of the week, probably get back to you saturday night with hopefully a working model.
Thanks guys
Josh

[jjandrj6679]

Hi all.
I have built cable, the switch board & installed the PCI Parallel card.
It lights up very dimly.
The top row of the dispay digits are all lit up, but I can't see anything from the bottom row.
The 100ohm trim pot works, although its realy looks dimmer than I was expecting.
The digits I can see do variate when I turn the 10k trim pot, although its too dim to see what is actually happening.
The tiny trim pot on the back of the LCD, turns the brightness up and down.
If after turning the tiny trim pot on the back of the LCD up further than it was at default setting and then turn the 100ohm trim pot up, the dispay is now quite bright.
For the mo I can handle it, it seems bright enough.

Ok so I think I am almost there.

So how do I get the LCD to display info?
I fiddled with Smartie and got the desktop display showing info, inc winamp plugin.

I have looked at the device manager and checked what port the Parallel PCI card was and it says LPT3.
So I set Smartie to port LPT3, applied, ok'd & then restarted Smartie, nothing changed.
Did as above except changed fro LPT3 to $378, applied, ok'd & restarted ...nothing had changed.#
So I'm puzzeled as to how Smartie works, is there a tutorial?

So where do I go from here.
Cheers guy I hope you can help again.
JJ

[Abi_J]

You will need to find the assigned address for your LPT port.

Open system (in control panel, or win+ pause/break key), click the hardware tab, the the device manager button.

In the new window, click the + next to ports, then double click the LPT port (I'm guessing LPT3 in you case).

Now click the resources tab, you'll see a bunch of numbers labeled as I/O Range, the very first number is what you need to know, most computers with built in LPT ports use 0378, but since yours is an add-on card, it will most likely be different.

In LCDS, in the Display settings area, make sure you have HD44780.dll as the driver, and enter the number you found above into the startup parameters area, I'm not sure, but I believe if the first digit of the number is a 0, then you replace it with $, so 0378 becomes $378, if it is any other digit then you just type it in as normal (again, I'm not 100% on that, I have build-in LPT ports on my machines that run LCDS).

Remember to set the screen size in the screen area too!

Hope this helps you get it working,
Abi.