robbo100
Posts: 60
Joined: Thu May 17, 2012 11:39 am

Re: Using Slice of Pi/o and 16x2 LCD at the same time?

Thu Jan 02, 2014 11:15 pm

Well, I thought it best to reply back to let everyone know that it worked!

I had already written the code for the LCD into my script before getting the LCD, and so wired it up and ran the code as soon as I could today. It worked first time, no need to debug, nothing! I am really delighted!

Anyway, just in case anyone doesn't know what a display looks like :lol: here are a couple of photos of the project.

Image

Image

Image

Image

Cheers all!

User avatar
Douglas6
Posts: 4783
Joined: Sat Mar 16, 2013 5:34 am
Location: Chicago, IL

Re: Using Slice of Pi/o and 16x2 LCD at the same time?

Fri Jan 03, 2014 6:47 pm

Congratulations! I wish any of my projects just worked on the first go.

robbo100
Posts: 60
Joined: Thu May 17, 2012 11:39 am

Re: Using Slice of Pi/o and 16x2 LCD at the same time?

Fri Jan 03, 2014 7:09 pm

Well, having said it works, it almost does.

I am having EMI problems whereby the display displays garbage when other high current devices are switched on (when they are on the same ring main)!

The Pi keeps running and still reports the right information via the print command in my ssh terminal, but the display goes mental. I have put a balun between the Pi and the display and things have improved, but it is essentially useless :-(

I bought two displays and the same problem exists with both.

robbo100
Posts: 60
Joined: Thu May 17, 2012 11:39 am

Re: Using Slice of Pi/o and 16x2 LCD at the same time?

Fri Jan 03, 2014 10:18 pm

Right, I found a fix.

I re-run the initialisation script whenever the temperaure up button is pressed. this makes the screen flash slighly when increasing the target temperature, but enables me to easily re-set the display if it goes crazy.

Not elegant, but good enough for me!

Mistertee
Posts: 24
Joined: Tue Aug 13, 2013 6:43 am

Re: Using Slice of Pi/o and 16x2 LCD at the same time?

Thu Feb 13, 2014 5:01 pm

On this page, there are links to a schematic and description of the Custard Pi 7 board, which has an LCD interface built on. It uses the I2C bus, so does not use any of the GPIO pins at all.

http://www.sf-innovations.co.uk/custard-pi-7.html

There is also a PowerPoint presentation with links to sample code that should get you up and running.

MarkDaniels
Posts: 59
Joined: Sun Oct 28, 2012 2:01 pm

Re: Using Slice of Pi/o and 16x2 LCD at the same time?

Thu Feb 13, 2014 5:23 pm

by Mistertee » Thu Feb 13, 2014 5:01 pm
On this page, there are links to a schematic and description of the Custard Pi 7 board, which has an LCD interface built on. It uses the I2C bus, so does not use any of the GPIO pins at all.

http://www.sf-innovations.co.uk/custard-pi-7.html

There is also a PowerPoint presentation with links to sample code that should get you up and running.
We also use the I2C interface to drive our LCDs from the Pi and have no problems with them even in a noisy industrial environment. I wouldn't consider doing it any other way. The hardware is slightly harder to do, but it only uses a single 8574 16 pin i.c. so it's really not that difficult and the results are so much better. The great thing with I2C is that you can string many devices off the same bus and it supports multiple bus masters, too. Just make sure you give each one a unique address ;)

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