I2C LCD Kit

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nated
 
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Joined: Fri Feb 28, 2014 6:55 am

I2C LCD Kit

Post by nated »

I ordered your 'new' (to me) I2C LCD kit and have some suggestions posted below.

The first kit purchased I accidentally soldered the PCA9685 IC in backward. Ironically i had it positioned correctly but took it out to adjust (bend) the pins and accidentally installed it backward and soldered it. While not a common mistake I found it nearly impossible to remove the IC without damaging the board. I ended up buying a second kit and will try to replace the IC with another PCA9685 I purchased from your store. The second kit I put an IC socket to avoid any installation issues or should for some reasons the chip be damaged to make removal easier.

Also on the first kit I dropped the LCD and the back light diffuser came out during de-solder of the PCA9685. I thought it an odd thing to happen. Can it be glued back in?


Suggestions are as follow:

1) add a socket for the PCA9685. Sockets are very inexpensive to add to the kit or final product.

2) Consider selling a fully assembled board. I love assembling electronics, but sometimes I just want a part that is ready to go and am willing to pay a few more dollars for it especially if I don't have the time to assemble it. (This applies to many kits)

3) The LCD backlight LED is not functioning properly on the second kit I purchased. The Green color sometimes does not light properly or is dim. I checked the connections to it, but I think it is a faulty LED in the display module (not sure how to fix that). I presume I could swap the LCD module with another one, but I'd rather not mess with de-soldering. Is there any other reason the green LED might not be lighting?

4) The I2C library appears to have a slow refresh with long lines of text (I'm not sure if this is an issue with the library or my implementation code). The documentation could be clearer as to what the library is doing and which functions it uses (the demo program compiles to more than 7k bytes). Does the code use any timers? It appears the loop issues the I2C command and holds up communications. This might be causing a blinking and slow refresh (I'm not quite sure though).


Its a great kit. Anyone looking for an LCD with minimal pin usage should check it out. Once I assembled it properly I was very happy with it. I'll buy another one for my next project.

I do wish there was one more button though (a back button) and maybe an SPI version since the I2C bus is only 100kHz without modifying it.

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adafruit_support_bill
 
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Joined: Sat Feb 07, 2009 10:11 am

Re: I2C LCD Kit

Post by adafruit_support_bill »

Thanks for the feedback. I will review it with the design team.
If you post photos of the front & back of the shield we'll see if we can spot any issues that might cause the backlight problem. From your description, it is most likely due to an intermittent solder joint somewhere between the IC and pin 17 of the LCD module.

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