trickierstinky
Posts: 17
Joined: Sat May 26, 2012 2:47 pm

Found an LCD in my old Electronics cupboard, any use?

Mon Jun 04, 2012 4:06 pm

Hi,

I yesterday I was sifting through my cupboard looking for stuff to clear out when I came across some ardunio pieces I had bought me and I found a LCD, not sure what model it is all I know it has never been used.

Basically I'm wondering if any can take a look at the photos and let me know if it is able to be hooked up to the Pi and if it is how (I'm new to electronics never done anything major).

I honestly don't think I would know where to start with wiring so, as dumb as you can make it the better.

thanks in advance

Doh! forgot the photos brb
Last edited by trickierstinky on Mon Jun 04, 2012 4:13 pm, edited 1 time in total.

godFather89
Posts: 150
Joined: Fri May 18, 2012 9:40 am
Location: Timisoara, RO

Re: Found an LCD in my old Electronics cupboard, any use?

Mon Jun 04, 2012 4:12 pm

trickierstinky wrote:Basically I'm wondering if any can take a look at the photos and let me know if it is able to be hooked up to the Pi and if it is how (I'm new to electronics never done anything major).
What photos?



User avatar
mahjongg
Forum Moderator
Forum Moderator
Posts: 12533
Joined: Sun Mar 11, 2012 12:19 am
Location: South Holland, The Netherlands

Re: Found an LCD in my old Electronics cupboard, any use?

Mon Jun 04, 2012 4:54 pm

Yes, you can control these from the GPIO's, if you use "nibble mode", you only will need six signals, four data signals and two control signals. These LCD's are 5V devices, but 3V3 levels are enough to control them.
You also need to apply a small negative signal for the contrast, I would recommend using an ICL7660 voltage inverter to generate -5V from the +5V, and a few resistors for contrast regulation. Examples you should be able to find in the datasheet of the LCD.

texy
Forum Moderator
Forum Moderator
Posts: 5160
Joined: Sat Mar 03, 2012 10:59 am
Location: Berkshire, England

Re: Found an LCD in my old Electronics cupboard, any use?

Wed Jun 06, 2012 12:30 pm

I,ve played with many LCD's over the years, and nevered needed a negative rails for the contrast. A pot between 0v and Vcc set to a voltage inbetween will do the job.

Texy
Various male/female 40- and 26-way GPIO header for sale here ( IDEAL FOR YOUR PiZero ):
https://www.raspberrypi.org/forums/viewtopic.php?f=93&t=147682#p971555

texy
Forum Moderator
Forum Moderator
Posts: 5160
Joined: Sat Mar 03, 2012 10:59 am
Location: Berkshire, England

Re: Found an LCD in my old Electronics cupboard, any use?

Mon Aug 06, 2012 10:12 am

Link?

T.
Various male/female 40- and 26-way GPIO header for sale here ( IDEAL FOR YOUR PiZero ):
https://www.raspberrypi.org/forums/viewtopic.php?f=93&t=147682#p971555

User avatar
mahjongg
Forum Moderator
Forum Moderator
Posts: 12533
Joined: Sun Mar 11, 2012 12:19 am
Location: South Holland, The Netherlands

Re: Found an LCD in my old Electronics cupboard, any use?

Sun Aug 12, 2012 1:14 am

texy wrote:I,ve played with many LCD's over the years, and nevered needed a negative rails for the contrast. A pot between 0v and Vcc set to a voltage inbetween will do the job.

Texy
It depends on whether the LCD is a text mode or a graphical display, both have very similar interface, and shape, but often graphical types needs a negative contrast voltage, while normal text mode LCD's do not.

SiriusHardware
Posts: 502
Joined: Thu Aug 02, 2012 9:09 pm
Location: UK

Re: Found an LCD in my old Electronics cupboard, any use?

Sun Sep 02, 2012 9:35 pm

mahjongg wrote:
texy wrote:I,ve played with many LCD's over the years, and nevered needed a negative rails for the contrast. A pot between 0v and Vcc set to a voltage inbetween will do the job.

Texy
It depends on whether the LCD is a text mode or a graphical display, both have very similar interface, and shape, but often graphical types needs a negative contrast voltage, while normal text mode LCD's do not.
Just to muddy the waters, I have come across HD44780 based Alphanumeric / Text LCD displays which DID require a below-zero contrast voltage on the contrast pin in order to achieve correct contrast and did typically require the use of something like a 7660 IC to generate the negative voltage.

However, all such displays that I have seen were from the first generation onto the market, typically with light grey backgrounds and fairly poor character contrast even when optimally adjusted.

All the newer ones I have seen (typically with green backgrounds) have worked with a contrast voltage in the range between V+ and 0V, usually somewhere just above - in fact you can usually just strap the contrast pin to 0V and they will work, albeit with the contrast a little on the strong side.

Return to “Other projects”