What is it?

This is a circuit board which acts as an adapter between the common I2C backpacks and the 0802 format display, providing a compact and tidy result. It works with the 14-pin and 16-pin display types.

Why did you make it?

I made one up by hand with proto-board and kynar wire and it took ages. Then I needed another one. So I made up 3 prototypes at OSHPark and put the extras on Tindie. Then I ran out. So it's now a product.

Instructions

• Place the display face down.
• Insert 2 x 7 header pins into positions 1-14, short end first. DO NOT SOLDER. On 16 pin displays, leave 15 & 16 open (they are the same as A and K).
• Insert 2 single header pins into position A and K, short end first. DO NOT SOLDER.
• Place the adapter board on the pins. Display pin 1 to board pin 1.
• There are two positions for A and K - move the single pins around for the best fit with your display - there appears to be no standard locations for these on the displays. The single pins have a bit of wiggle, so it's ok to lean them a bit if needed.
• Solder the headers to the adapter board. DO NOT SOLDER TO THE DISPLAY.
• Lift the adapter board off the display.
• Trim off the long ends of the header pins with wire cutters. Eye protection is advised - those things fly!
• These instructions assume that the I2C adapter has the 16 pin header already installed. If not - you need that done before the next step.
• Insert the I2C module into the adapter board - on the other side from where you had the display. The GND pin on the I2C module is closest to the 14-pin header. Look at the picture.
• Solder 1 pin on the I2C module, then straighten it up. Then solder the other 15 pins.
• Trim off the long ends of the header pins with wire cutters.
• Position the display back on its headers.
• Solder the 16 pins to the display.

Notes:

• The I2C modules which I supply include a jumper to the backlight circuit. My preference is to solder a 330R resistor in that position as a current limiter, at least on 5V projects. probably not needed on 3.3V
• These modules also include the contrast pot and address jumpers. Default address is 0x27.
• I2C bus requires pullup resistors somewhere on the bus. 4.7K usually does the trick.
• I use this library for these displays.