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How to Connect Non-gadgeteer LCD Display to FEZ Cobra II (Eco) or FEZ Spider


#1

Hi Everyone,

I am trying to start my first project to create a monitoring device which takes sensor measurements and displays them on a 20 character x 4 line (black on green) LCD screen.

Unfortunately, no such screen is available on GHIelectronics so I tried to find it on a different site but none of them have this screen with a gadgeteer connector on it.

Ideally, I was after a screen like this one,
https://core-electronics.com.au/lcds-displays/character-lcds/i2c-twi-lcd2004-module-arduino-gadgeteer-compatible.html
, only in black-on-green instead of white-on-blue.

However, all I could find was this screen
https://core-electronics.com.au/lcds-displays/character-lcds/basic-20x4-character-lcd-black-on-green-5v.html
,and this other one which is also “serial-enabled” (I dont’ understand what this means!?!),
https://core-electronics.com.au/lcds-displays/character-lcds/serial-enabled-20x4-lcd-black-on-green-5v.html
, but I do not know how to connect these to the FEZ.

There used to be a product which converted the LCD pinouts to a Gadgeteer connector plug,
http://au.mouser.com/ProductDetail/GHI-Electronics/HD447-GM-358/?qs=%2Fha2pyFaduiZ3rYL62UhWSwXIvvICxHKJiQCJ%2bJ2VovLuVVnkEWTAw%3D%3D
, but it is nearly impossible to find and also discontinued.

Does anybody know how to connect these non-gadgeteer LCD screens to the FEZ boards? Or how to modify a gadgeteer conection cable to attach one end to these LCDs (e.g. strip the wires for the plug on one end of the cable and solder them to the LCD board, then plug the other end straight into a FEZ board gadgeteer plug).

Also, not to rush this, but if possible I would like to understand this before the end-of-year discount expires.

P.S. Image files are attached in order of reference to products in my post.

Thanks for any help,
hotdog


#2

@ Hotdog, welcome to the forum. As you point out, the easiest way is to the the HD44780 Module ( https://www.ghielectronics.com/catalog/product/358 ). However, if you can’t get hold of one you could make your own using something like this https://www.ghielectronics.com/catalog/product/405 and the schematic for the display board ( http://www.ghielectronics.com/downloads/schematic/HD44780_Module_SCH.pdf ).

Alternatively, depending on your coding / electronics experience you could look at using an I2C LCD which would only require four wires. There are several examples on Codeshare including this one ( https://www.ghielectronics.com/community/codeshare/entry/925 ) which uses a Midas 16x2 LCD.

Hope that helps and good luck.


#3

Just re-quoting your links so they become visible.

You should update your profile with your location as I think I may be able to help you :slight_smile:

Ultimately the HD44780 module does a few things - maps pins in a socket to pins that end up on the LCD pinouts, as well as providing some control for the backlight. Depending on what you have access to (like Extender modules or G-Plugs) you may have a way to wire those up - again depends if you want to get significantly into a Gadgeteer module look-alike or if you just want to get something working. More than happy to try to help out in either way, and depending on where you are in AU I might have a HD44780 module you can have for Christmas !


#4

I have connected a groove oled128x64 (http://www.seeedstudio.com/depot/Grove-OLED-Display-112-p-781.html) to my cobra board, see this trhead:

https://www.ghielectronics.com/community/forum/topic?id=17351


#5

Hi All,

Thanks for your replies.

Just a quick note, I spent a good 40 minutes typing up a detailed reply to everyone, but when I went to submit it the website said I had to login again to finish posting it and naturally after I logged in it said it was unable to post my message :wall:

So this time I willl just keep my reply brief.

I am not very experienced with coding and electronics so the simpler everything is the better.

Would I2C be much harder to program for than Gadgeteer connections, and would I lose any features using I2C?

For making my own module connection with the breakout board, according to the schematics for 0 Ohm and DNP resistors should I just use plain wiring without resistors for those parts.
Also, for the transistor is it okay to use any model 3904 transistor such as ht@ tp://au.rs-o@ nline.com/web/p/bip@ olar-transistors/7930753P/ ?

Also, I have seen that 4xLine LCDs use two standard gadgeteer plugs, while 2xLine LCDs only use one (but both only use one I2C plug). Would this complicate connection to the breakout boards and would it effect use of I2C?

I am not fussed if I just strip one end of a gadgeteer connector cable and solder it straight to the LCD provided it doesn’t lose any functionality and that this would actually work.
Or alternatively if it is possible to just connect (using wires) the LCD to the row of pin holes on the FEZ Cobra II (Eco) then I could make do with that?

@ Brett thanks for the offer of a HD44780 module, but I was hoping for some sort of repeatable method or commonly (more than a couple) available component so that if this project turns out good then I can get/make some more for additional projects. That’s why I am hoping to figure out a simple way to connect the LCDs to the FEZ boards.

@ geologic thanks for the link and code example, I was considering doing another project which uses an OLED or Graphical LCD display which can display form windows made in C# with Visual Studio. Do you know if the OLED (or any LCD) can handle this capability of displaying forms? Or would I need to try running an Operating System on the FEZ to do it?

Thanks for all your help so far,
Hoping for some more :D,
hotdog


#6

Well I was going to firstly reply that my suggestion was to move to an I2C display module, they’re relatively easy. But then I thought why - when really if this becomes a seller you’re going to package this up in something that won’t rely on Gadgeteer sockets anyway, so perhaps it won’t be an issue if you rely on a single module in your prototype phase? Failing that, go to an I2C module, but be careful, just because a seller says “Gadgeteer” doesn’t mean they know what it means and that they have the pinouts correct on the Gadgeteer socket :slight_smile: Perhaps they really just mean it has the same header as Gadgeteer uses :slight_smile: :open_mouth:


#7

this works fine for control signals but is sometimes less simple for the power related lines for an LCD as you likely need to have a contrast adjustment control, and possibly need the backlight control. ( I made a homebrew adapter that has transistors on so you can use PWM from a pin to control both the contrast and the backlight, as well as sending the pwr/gnd pins to the module as needed ) Many different ways to achieve the same thing :slight_smile:


#8

Not sure but it sounds hard to me to display forms like you want on this kind of oled devices.
I use groove oled to plot simple text, and it is possible to draw simple geometric objects like lines, circles, but no more than that.


#9

What you want to look for is a screen that supports Glide. That usually means one of the R/G/B socket screens like the TE35 https://www.ghielectronics.com/catalog/product/387