Anyone who has seen my unfinished post about the I2C LCD backpack probably thinks that is a long time forgotton project. Not really, I just wanted to take it a step farther than I had and didn’t. That is until now. I just discovered a very reasonable prototype PCB manufacturer. Where for a board that is less than 2″ x 2″, you can get ten boards for less than $20 shipped. Yes, less than $2 per board shipped. When I found that, I couldn’t pass it up. So, I finalized my board design and ordered them.
These boards are purchased from and shipped from China so I was expecting a long delay. I must say though, I was pleasantly surprised. I placed my order on February 4th and sent my files to them via email. I got a response from them that they had sent my designs to the fabricator on the 5th. On the 14th, they flagged my order as “Delivered” (Really meant shipped). On the 20th, Hong Kong tracking said it left Hong Kong. And on the 27th, they were at my home in N/W Indiana. Pretty good for a start to finish.
The boards look great too. Here is a shot of the front and back of the board.
As you can see, the boards look good.
I did have one down side. When I designed my backpack, I used a port expander I had sourced from Maxim. It was a MAX7318AWG. Since then, this part doesn’t seem to be available anywhere. While there is a suitable pin for pin alternative, the MAX7311AWG, they are a bit pricey where I did find them. Oh well, at least the boards will be usable :D.
I had on hand all the components to build the board except for the SMD Potentiomenter for contrast. I know however, as long as the contrast line is biased to ground with a 1K resistor that the contrast works. So, I just installed a 1/8W 1K resistor in place of the pot.
Here is the end product.
I have zipped up the files for the board, the Gerbers for manufacture (If you want), and the test program and libraries. They can be downloaded here http://www.rs-micro.com/files/I2C_LCD.zip.
This project was designed around a NerdKit. The library files should be placed in the same folder as the default NerdKit libraries (libnerdkits).