Check the kit against the parts list to verify you have all the parts necessary
We recently adjusted the kit so the buttons are on the right side instead of the left. The parts list is otherwise the same, its just a little more stable than before
We'll start with the first resistor GREEN - which has orange, orange, brown, gold bands on it. This resistor acts as the backlight control resistor for the green backlight pin.
Bend the resistor into a 'staple' and slide it into the slot marked GREEN on the PCB. Resistors do not have a direction so you can put it in 'either way' and it'll work find.
Bend the 'legs' of the resistor out so it sits flat against the PCB and flip it over.
This way the resistor won't fall out while soldering.
With your soldering iron heated up and ready, solder in both leads of the resistor. To do this, heat up the round ring pad and the wire lead at the same time for 2 or 3 seconds, then dip the end of the solder into the heated joint to melt it in.
Then remove the solder and the soldering iron.
Since you did so great with the first resistor, we'll place all of the rest now at the same time.
The two 220 ohm resistors RED and BLUE - named because they are the backlight series resistors for the RGB backlights on the LCDs. These resistors are colored Red Red Brown Gold.
Next up we will place the buttons. These buttons are useful to send a signal to the Pi (say if you have a basic menu system). We have a 4-way 'direction pad' for up/down/left/right input and a button to the right called SELECT. These 5 buttons should be able to make 'talking' back to your project easy. These are connected to the I2C port expander chip so they require no extra pins on the Pi, our library does the work of reading whether they are pressed.
All the buttons are the same, and they should snap nicely into place. Press down onto each button until it snaps in and sits flat against the PCB.
We recently adjusted the kit so the buttons are on the RIGHT side instead of the left. The buttons snap in the same but they're on the right
Solder each leg, taking care not to accidentally 'short' two button legs together. The ones for the directional pads are very close!
Next, place the 10K potentiometer (the orange-faced thing with three legs) into the spot above the RESET button. It will only fit one way. This is the contrast potentiometer which will adjust how dark the characters appear. All displays are slightly different so you'll adjust this once the display is soldered in.
The kit may come with two potentiometers - a big blue one for
breadboarding the LCD and a smaller orange one for the shield kit. You
can throw away or recycle the blue one, use only the orange one here!
We recently adjusted the kit to have the potentiometer in the center rather than the right, goes in the same way, just in the middle!
We're nearly done! Now we will place the I2C port expander chip. Double check that it has the MCP23017-E/SP marking on it. This is a 16-pin expander chip, that uses the i2c bus. That means you can send it commands using the i2c pins on an Pi and control 16 more digital pins! 5 of those pins go to the buttons, 6 go to the LCD control and 3 are used for the backlight (the remaining 2 are unused).
Unlike buttons or resistors, chips do have a direction and the must be put in the right way! First, use a flat table to carefully bend the legs of the chip so they are parallel. Then slip it into the silkscreened outline so that the notch at the end of the chip is on the right. Click the image to the left to make absolutely sure you've got it in the right way. Once you are sure, press the chip into place
We recently adjusted the kit so the chip is more to the left, its the same alignment, just shifted over
On kits where the buttons are on the left, put it right below the contrast pot, as shown. This will keep the pot from touching the Ethernet jack.
On kits where the buttons are on the right, put it right next to the buttons (it shouldnt overlap any button legs) sitting flat
Solder in one pin, we suggest the top right, then check if the plate is sitting flat. If not, heat up the joint with one hand while stabilizing with the other until its right.
Then solder the other 25 pins
Break off a piece of 18 or 16 pin header from the stick in the kit.
If you have an RGB display, you'll need 18, for a blue&white you'll need 16
Place the header into the remaining slot with the long ends of the pins sticking UP. If you have only 16 pins, leave the two rightmost pads empty
Your LCD may have two rows of connectors or one row. If its a two-row-connector LCD we do not use the bottom row, just continue using the LCD as it will fit just fine!
The LCD should 'snap' in against the buttons
Solder all the pins!
With the new Raspberry Pi model B+ and its extra USB ports there's a slight problem with the layout of the character LCD shield. As you can see in the photo below, the three through-hole backlight resistors have their leads right above one of the metal USB ports. Unfortunately these leads are quite close and can potentially short against the metal USB port.
Note that if you are using a Raspberry Pi model A or B (i.e. Pi with only 1 or 2 USB ports) you can skip this step and move on. You only need to add this tape if you're using a Raspberry Pi model B+, the Pi with 4 USB ports.