ComputerVoltageSources

Got my LCD this weekend from Mouser and got it interfaced to my AVR
development system. Got it operational with my software. I put a
picture of it in my photos folder. I haven't played around with the
backlight current yet. The LCD in the picture is running a backlight
current of 45 mA(Rs=22 ohms to 5 volts). It's a nice display.

The mounting holes match up to my panel. However the display portion
of panel is narrower than the panel. I'll have to carefully measure it
and update my drawings.

I'll also write a program to verify the character set and make sure it
matches my display specification.

Dave

I used my metric calipers to measure the display. The mounting
dimensions are good as is the height of the opening at 16 mm. However
the width is smaller than the 66 mm specified on the drawing. I ended
up using the following dimensions:

mounting hole 2.4 mm for 2-56 screw
display opening height of 15.5 mm
display opening width of 64.5 mm

Note the display opening is not centered with the mounting screws.

I updated all of my fpd files. I verified the DJB-CVS 4-CIN expansion
(4-3-06).fpd file by printing a copy and laminating it to foam core
and mounting a display. I put a picture in my photo folder. Note
that while I updated the other files, I did not verify them.

The display also has a jumper and mounting for a SMT resistor to power
the backlight from the +5 volts on the 14 pin housing. I added a 27
ohm resistor to mine which drives the backlight at 38 mA. This is a
reasonable brightness and will limit the power dissipation in the 7805
to about 1/2 watt at +15 volts.

The contrast (pin 3) can be directly wired to ground. However, a
slight voltage higher will eliminate seeing the background of the 5x7
dot matrix which is an improvement. I used a linear potentiometer and
the entire range is only about 10 degrees of rotation.

Dave

> The LCD in the picture is running a backlight
> current of 45 mA(Rs=22 ohms to 5 volts).

You're right, the LCD mounting holes are for tiny 2-56 mounting screws.
Fortunately Digi-Key appears to have a wide selection of 2-56 threaded
standoffs.

According to this screw reference web page, we could go a little smaller on
the mounting holes:

http://www.marfas.com/machinescrewtapping.shtml

Close fit drill size 43, diameter .0890
Free fit drill size 41, diameter .0960

John Loffink
The Microtonal Synthesis Web Site
http://www.microtonal-synthesis.com
The Wavemakers Synthesizer Web Site
http://www.wavemakers-synth.com

> -----Original Message-----
> From: ComputerVoltageSources@yahoogroups.com
> [mailto:ComputerVoltageSources@yahoogroups.com] On Behalf Of djbrow54
>
> I used my metric calipers to measure the display. The mounting
> dimensions are good as is the height of the opening at 16 mm. However
> the width is smaller than the 66 mm specified on the drawing. I ended
> up using the following dimensions:
>
> mounting hole 2.4 mm for 2-56 screw
> display opening height of 15.5 mm
> display opening width of 64.5 mm
>
> Note the display opening is not centered with the mounting screws.
>