Serial LCd

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

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

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

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

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

that’s is easy …

Parallax 4x20 Serial LCD Parallax 4 x 20 Serial LCD with Piezospeaker (Backlit) - Parallax or Parallax 2x16 Serial LCD Or any Serial Enabled LCD Module from Sparkfun.

I have NetMF Drivers for thesed if you need it.

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!

These guys have a few to choose from.

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

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

There’s lots of them, though:

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

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…

gadgeteer or other ok

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 Arduino UNO Tutorial 10 - LCD and the BL circuit is a typical transistor driver (like is on this one even though it’s connected to the contrast Electronic circuits - PCB Heaven 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.