Nice source for 2x40 LCD Displays

[THeff]

Hi All,

If you are looking for some 2x40 LCDs, you may want to checkout BG Micro for part # LCD1025.  http://www.bgmicro.com  They sell these brand new LCD displays as part of an assembly mounted in a frame with another PCB.  The LCD is mounted with screws and is plugged in, so no soldering is required to remove it.  The LCD has LED backlighting.  The cool thing is that the other PCB has (3 ea.) 74HC595 ICs, (1 ea.) 74HC165, an LED bargraph display, and other misc. components.  The only down side is that the LCD display requires ~-2V on the contrast pin for good contrast.  The single price is $5.95 or $4.67 if you buy more than three.  I bought 10 a while back and just started using them on the MB SEQ and MB SID and they work great.  You will have to unsolder the ICs if you want them but the pin leads have not been trimmed, they are full length.  I even unsoldered the 16 pin header connector and re-used it for the LCD.

Tim

[Sasha]

The only down side is that the LCD display requires ~-2V on the contrast pin for good contrast

What exactly does it means? Do you have to make some modifications to suit MB?

[MTE]

wow...they´re really cheap :)

[THeff]

"The only down side is that the LCD display requires ~-2V on the contrast pin for good contrast"

Yes,

The CORE module has to be modified slightly.  The original design has a 10K pot for the LCD contrast.  The connections to the pot are (1) ground, ((2) wiper) LCD contrast pin, and (3) +5V.  The +5V connection to the pot has to be removed and you need to supply negative 2 Volts to pin # 3 of the potentiometer.  I have a +/- 12 V supply for the AOUT module, so it was just a matter of connecting a 1K resistor to the -12 V and the other end to the pot along with a 2 - 3 V zener diode to ground ((cathode/stripe) to ground, anode to pot pin #3 ).  I used a 3 V zener because I had several lying around.  You only need about 1 mA of current for the negative LCD voltage.  You probably could use 3 or 4 regular 1N914 switching diodes in series in place of the zener.  Just place them in the opposite direction of the zener because you will be using the forward drop voltage and this should give you about 2.1 Volts.  Once this mod is done you adjust the contrast with the 10K pot just like the original design.  BTW, BG Micro has a data sheet for the display on there web sight in the technical documents section.

Tim 

[docbrown]

Or, you could use one of these babies: http://www.maxim-ic.com/quick_view2.cfm/qv_pk/1017 for your contrast voltage.

thanks..

[Sasha]

Thanks. Maybe I order this display now.

[docbrown]

If in case you cant find the MAX1044 or the compatible, you could make a negative 5volts voltage inverter out of a 555 timer.

cheers!! :)

[THeff]

I have used the 555 timer circuit that you showed several times in the past and it does work very well.  If this LCD is for the SID, you could probably use the 1 MHz PWM clock coming out of the PIC to drive the capacitor/diode network as well.  Especially since you only need to "steal" about 1 mA from the clock.  The electrolytic coupling capacitor could probably be reduced in value since the clock is 1 MHz and this would provide less of a load on the clock line.

Tim 

[Dolphinicus]

Hi All,

If you are looking for some 2x40 LCDs, you may want to checkout BG Micro for part # LCD1025.  http://www.bgmicro.com  They sell these brand new LCD displays as part of an assembly mounted in a frame with another PCB.  The LCD is mounted with screws and is plugged in, so no soldering is required to remove it.  The LCD has LED backlighting.  The cool thing is that the other PCB has (3 ea.) 74HC595 ICs, (1 ea.) 74HC165, an LED bargraph display, and other misc. components.  The only down side is that the LCD display requires ~-2V on the contrast pin for good contrast.  The single price is $5.95 or $4.67 if you buy more than three.  I bought 10 a while back and just started using them on the MB SEQ and MB SID and they work great.  You will have to unsolder the ICs if you want them but the pin leads have not been trimmed, they are full length.  I even unsoldered the 16 pin header connector and re-used it for the LCD.

Tim

Thanks greatly for posting that!  :) I found it in my searches on here for the availability of 2x40 displays, in North America. :)  I've placed an order for 4 of them. :)  Under $20 U.S.!  Woohoo! :D

By chance - would you have a photo of them in operation, so I can see what they look like in action?  I read something about 'blue / black / grey background' in their display mention.  That'd be even cooler to me, as I was hoping to get away from the yellow background type of display. :)

[Dolphinicus]

Has anyone out there had any bad experiences from BGMicro?

I still haven't seen the 4 2x40 displays that I ordered, 3 weeks ago.  I sent them email inquiring about shipping time / tracking # / etc., almost a week ago, and haven't had a reply at all.  The order were under $20 U.S., but I'm still a little bit concerned, as the final parts that I need for my MIDIbox SEQ will here any day and I'd like to build the unit with more than the single 2x20 display that I have at the moment.  :o

Thanks for any help / thoughts. :)

[ultra]

docbrown: does it matter if i get the  ICL7660 or  MAX1044?  i'm assuming 1 per lcd?

excuse me if my questions are obvious.  i'm new to electronics (and extremely excited).

[Dolphinicus]

Shipping time from BG Micro in Texas, U.S.A. to Southern Ontario, Canada was 20 days!  :o :o

I received my 4 displays yesterday though. :)  Very impressive.  NEW.  A little bit of desoldering as well, but that'll give bonus parts!  Woohoo. :)  Shipping from them to other parts of the U.S. will definately be quicker. :O :)

Shipping costs to Canada (for other Canadians) were $10.00 U.S.

Shipping outside of North America is listed at, at least, $15.00 U.S.  Just so any others, know. :)

Now to get started on laying out my tact switches / siliconed LEDs above them, circuit board. :)  I hope to have this entire unit together, before Christmas. :)

I'll have to make some custom knobs for it as well. :D  Speaking of that - I'm making my own knobs for my modular, out of wood.  If anyone would like to see my first examples, I have a new pic up at my website, showing the 28 that I have done, out of the 145 that I need right away. :)

http://www.sdiy.org/damian/index.html

[stryd_one]

Nice :) Sometimes I swear you'd mine the copper for your own PCBs if you could!

[Dolphinicus]

Nice :) Sometimes I swear you'd mine the copper for your own PCBs if you could!

Y'know?  If I had an easy way to recover the copper from used PCBs - there's a HUGE WEALTH of 4 layer PCBs (BLANK!! :o :) ) at work that I could salvage.  ;D

In the mid 90's though, I bought a 4' x 3' piece of single layer copper board for only $86 Cdn.  I still have over half of it left.  It's been wonderful for all of my PCB manufacturing ever since - so, no mining to do. ;)  :D

[docbrown]

docbrown: does it matter if i get the  ICL7660 or  MAX1044?  i'm assuming 1 per lcd?

excuse me if my questions are obvious.  i'm new to electronics (and extremely excited).

Ultra,

I personally used the MAX1044, but I think they are both pin compatible. And yes, you might need one per LCD, it depends, since some LCD's (even the same model) might react differently on negative voltage. Try using one first, if it looks ok.

cheer!!

[ultra]

docbrown: i am new to this.  do you have a photo of how you wired in this ic and what is replaced on the core?  i bought these lcds and i'm almost ready to hook them up!

[ultra]

thanks that 555 circuit works great.  i discussed this circuit on irc with someone and changed the resistor and capacitor values based on what i had laying around.  also, this works without the zener diode.

[docbrown]

docbrown: i am new to this.  do you have a photo of how you wired in this ic and what is replaced on the core?  i bought these lcds and i'm almost ready to hook them up!

Sorry, haven't been here much lately. Let me know if you still need that photo.

[ultra]

[DrBunsen]

Has anyone out there had any bad experiences from BGMicro?

I still haven't seen the 4 2x40 displays that I ordered, 3 weeks ago.

Mine and stryd_one's arrived quickly.  Have you seen yours yet?

[dj3nk]

nice topic but .......

wrong place in this forum.