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Serial LCd


#1

anyone recommend a serial LCD for my G120 project? Are all the serial LCS the same, i saw some on sparkfun and ebay?


#2

How about those from 4d Systems over in down under …

http://www.4dsystems.com.au/


#3

Already using the 4d systems lcd but want have the ability to use a cheaper 2x16 LCD version


#4

I’m using the GHI (LCD 2x16) one as well, but that requires a Gadgeteer Y-Socket…


#5

I’ve seen I2C character 2x16 display on ebay. Can’t give the link, though… But they really exist :slight_smile:


#6

that’s is easy …


#7

Parallax 4x20 Serial LCD http://www.parallax.com/product/27979 or Parallax 2x16 Serial LCD http://www.parallax.com/product/27977. Or any Serial Enabled LCD Module from Sparkfun.

I have NetMF Drivers for thesed if you need it.


#8

thank you people…i think my board design is complete! 2 years in the making…lets hope other people will get value from it, else i will have the most expensive automation system for my home ever built!


#9

These guys have a few to choose from.

http://www.newhavendisplay.com/serial-displays-c-253.html?zenid=rdndkd33fa1i2i0dh22o2ivm21


#10

I have used these displays with good success. (Not on .NET MF but on an older application.)
They have a lot of options.

http://matrixorbital.com/


#11

16x2 with a serial (I2C) interface board, $3.99 delivered from China.

There’s lots of them, though:

http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=hd44780+serial&_sop=15


#12

thanks…didn’t realise they all use the same chip? Was hoping to be able to control the contrast by software also.


#13

you need to do something special for contrast (and typically backlight). Most of these I2C or SPI-like devices are just converting the data/clk connections on the HD44780 into a serial stream with less connections; you really need to have electronic circuitry to control BL/Cont, and then use something like PWM to change them. I think I have an old eagle board I designed that had this if you want to look at it ? Do you want Gadgeteer connection or other - IIRC I had something like a 6-pin x2 rows 0.1" shrouded header on there because I didn’t have any desire to reduce the data pins…


#14

gadgeteer or other ok


#15

I checked out a couple of the LCDs mentioned here (specifically the devantech) and some of them actually do have software commands to adjust backlight and contrast, so maybe they are ok ? I was mainly going off what I’d seen when I was looking for LCDs in the Fez Domino era, looks like a few other people have added more features now!

Found my circuit. Simple PWM controlled contrast and backlight signals, via a capacitor for the contrast and via a transistor/capacitor for BL. The really simple contrast circuit is described http://www.hobbytronics.co.uk/arduino-tutorial10-lcd and the BL circuit is a typical transistor driver (like is on this one even though it’s connected to the contrast http://pcbheaven.com/circuitpages/ PWM_LCD_Contrast_Control/). The reason the contrast can be adjusted with just a capacitor is that the contrast is looking for a small voltage that it then uses as a differential reference to the supply voltage, whereas the BL needs to draw a much larger current and a transistor is the simplest way to do that.