LCD shield and/or LCD serial backpack

looks like you have to be registered to get the file from megaupload!? maybe rather post an image file, so we can see it here?

looks like you have to be registered to get the file from megaupload!? maybe rather post an image file, so we can see it here?

kuk, you just have to wait a minute before it does the download. The invitation to register is for instant downloads.

I got the file and a quick glance on eagle looks good. But I don't have enough PCB design experience to review the design.

ah, thanks. i think i got distracted by the german translation of the page :slight_smile: looked like a redirect.

kuk, es gibt kein problem :slight_smile:

cheater, I have 3 or 4 LCDs in my parts box and wonder if its worth testing the contrast and backlight circuits on them using my arduino. If you want to modify the transistor driver code so it works with the arduino's timers running on a 16mhz clock then I would be happy to test this on my breadboard.

I don't need the code for the LCD data for this test but would be happy to look at that if it would help you.

Thanks mem. I'd love it if you could test PWM with a 0.1uf capacitor on the contrast.
I'd do it but I dont seem to have any transistors around. I could scrounge one....

No code yet. I'll whip it up once I get the PCBs. :slight_smile:
Just test with AnalogWrite for now.

I've created a Sourceforge project for this to keep everything nice and tidy.
I'll be setting it up today.

Just tested (very roughly) without a transistor and it seems that the contrast acts just like a normal LED.
Ripple isnt a problem. A 0.1uf capacitor should just smooth things out a bit though.

Ok last questions:
Is a resistor required on the LCD's backlight? Sparkfun doesnt use one. I'd imagine it would be fine.
And is a resistor required on the transistor's base? I wouldnt think so.

I will be rather happy if I can ditch two resistors. :slight_smile:
I'll then be able to order.

Current parts list (assuming I can ditch two resistors):
2x 0.1uf 0805 capacitor
2x BC817 SMD NPN transistor (0.8A max)
1x 10k 0805 resistor
1x ATmega8 QTFP

My bad. The ATmega8 doesnt have enough PWM and I forgot about slave select. :slight_smile:
I've now got it with a ATmega168 which has more PWM and more space which should be good.

Just a update: I have the OpenLCD website up.
http://openlcd.sourceforge.net/

Eagle files (completely different to whats posted above) are in SF's release system.

Can someone do a quick check on the circuit to make sure it will work before I order a large stack of them?
I figured that its only slightly more to get ~138 of them as it is to get 25 of them so why not.
I dont want that many coasters though. :wink:

Just a question: You do not provide a ground signal to your SPI, SER and I2C connectors. I would have expected these to have a ground since they are not differential. Am I missing something?

Cheater, The 3d view shows the header pins for the LCD and arduino interface on the same side of the board. If I am visualising this correctly, I presume the arduino interface header will be mounted on the opposite side of the board to the LCD header.

Just a question: You do not provide a ground signal to your SPI, SER and I2C connectors. I would have expected these to have a ground since they are not differential. Am I missing something?

Yes your missing the 5V and the GND connector on it. :wink:
The user will have to connect all the grounds together themselves if power and signal are coming from two different sources.

Cheater, The 3d view shows the header pins for the LCD and arduino interface on the same side of the board. If I am visualising this correctly, I presume the arduino interface header will be mounted on the opposite side of the board to the LCD header.

Yep. The 3d view looks pretty but its not perfect.

Btw xSmurf made me add RS232 to the list of interfaces it supports. :slight_smile:
Going to see if I can fit a crystal on it, if not then I'll order.

There was a demo of a LCD shield at the last NYC hack lab.

Well 100 PCBs are now coming to me along with 4,000 capacitors and 5,000 resistors. :slight_smile:
I'll have enough to populate 30 PCBs. The Atmel chips get expensive quicky ($100 for 30).

Around half are earmarked for this first run so about 10 will be for sale. :slight_smile:
If they are popular then I can have another batch ready within about 5 days after that.

There was a demo of a LCD shield at the last NYC hack lab.

Interesting. Got a url?

A shield is great for some things... particuarly "plugging in" lots of connections to something external. However, to add an LCD panel to my Arduino, I only need to tap the serial line and 5v and 0v if I spend $8 for a complete kit of parts (except the panel itself) for the great little LCD panel controller from ModernDevice.com (no "S" in that). It is an implementation of Peter Anderson's #117.

"Except the panel..." The kit lets you interface a wide range of panels to the Arduino. Hence the need to purchase it "separately". ModernDevice offer a selection. Some only $12, if memory serves.

It should even be possible to drive the thing from something other than the serial out pin, but that would entail a little more software work. If you are willing to use the serial pin (and that won't stop you uploading programs to the Arduino) then all you need is.....

setup()
{
serial.start(9600);
}
loop()
{
serial.Print("Hello world");
}

Why reinvent an already available wheel? There are so many other worthy projects waiting out there!!

(My only association with ModernDevice: Happy customer.)

A shield is great for some things... particuarly "plugging in" lots of connections to something external. However, to add an LCD panel to my Arduino, I only need to tap the serial line and 5v and 0v if I spend $8 for a complete kit of parts (except the panel itself) for the great little LCD panel controller from ModernDevice.com (no "S" in that). It is an implementation of Peter Anderson's #117.

"Except the panel..." The kit lets you interface a wide range of panels to the Arduino. Hence the need to purchase it "separately". ModernDevice offer a selection. Some only $12, if memory serves.

It should even be possible to drive the thing from something other than the serial out pin, but that would entail a little more software work.

Why reinvent an already available wheel? There are so many other worthy projects waiting out there!!

(My only association with ModernDevice: Happy customer.)

If TTL serial is the only interface required then the board kit in your link is a dollar cheaper (on the moderndevice.com page its shown as $9 plus shipping). But for some applications (like mine), the hardware serial port is not available (its used for data logging to a PC) and the baud rate (even at 19200) is too slow to use a software uart. For those of us that have real time applications that need something like an i2c interface, a serial only board won't cut it.

But even if my application didn't require the higher prformance, the board being discussed in this thred has greater appeal for me because for the cost of an extra dollar its much more flexible than a serial only board.

Why reinvent an already available wheel? There are so many other worthy projects waiting out there!!

Reasons?
I can list them:

  • Mine is faster and can do more. (ATmega168 vs PIC with 4k flash)
  • Mine is completely open, both hardware and software. The 117 is code protected and no source is provided.
  • Mine has four different interfaces (SPI, I2C, TTL Serial and RS232) compared to only TTL Serial on the 117.
  • Mine is cheaper. $10 for premade and $8 for a kit (SMD components however).
  • Mine is significantly smaller. Under a third of the size of the ModernDevice board.
  • And probably a few other reasons I've forgotten. :slight_smile:

I actually wanted to buy a serial LCD controller but I couldnt find any which were half decent.
They were all closed source and only had TTL Serial and maybe RS232 interfaces.

Also I have a source which sells LCD panels at $7.90 for 16x2 with backlight in single quantities or $5.90 in bulk.
$12 can buy two. :wink:

[EDIT] Oh and if these LCD controllers are popular then I will be going on to tackle things like graphical LCDs and other trickier hardware. [/EDIT]

I thin the other reason is that it is a lot of fun :slight_smile:

The 16x2 LCD board is great and I would also be interested in the Graphics board. I am thinking of using this with "sensor shields", e.g. I want to monitor the depth of a water tank using a pressure sensor.Chris

I thin the other reason is that it is a lot of fun :slight_smile:

Oh of course. :smiley:

Why reinvent an already available wheel? There are so many other worthy projects waiting out there!!

Reasons?
I can list them:

  • Mine is faster and can do more. (ATmega168 vs PIC with 4k flash)
  • Mine is completely open, both hardware and software. The 117 is code protected and no source is provided.
  • Mine has four different interfaces (SPI, I2C, TTL Serial and RS232) compared to only TTL Serial on the 117.
  • Mine is cheaper. $10 for premade and $8 for a kit (SMD components however).
  • Mine is significantly smaller. Under a third of the size of the ModernDevice board.
  • And probably a few other reasons I've forgotten. :slight_smile:

I actually wanted to buy a serial LCD controller but I couldnt find any which were half decent.
They were all closed source and only had TTL Serial and maybe RS232 interfaces.

Also I have a source which sells LCD panels at $7.90 for 16x2 with backlight in single quantities or $5.90 in bulk.
$12 can buy two. :wink:

[EDIT] Oh and if these LCD controllers are popular then I will be going on to tackle things like graphical LCDs and other trickier hardware. [/EDIT]

I'm convinced. I'm currently enjoying my relationship with I2C so I'm keen to see what else I can add to the chain.

So, for 2 units ($20) including 2 16x2 LCD panel's ($12), it's $32 + shipping. Sounds a bit light.

When will they be available off-the-shelf?

Just a question: You do not provide a ground signal to your SPI, SER and I2C connectors. I would have expected these to have a ground since they are not differential. Am I missing something?

Told you Cheats...