Assembly

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

Put the printed circuit board into a vise or board holder, heat up your soldering iron and make sure you're ready to go!

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.



Once the soldering is complete, we can clean up by clipping the leads of the resistor. This keeps them from shorting to something else. Use diagonal or flush cutters to clip the wires right above where the solder joint ends.

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.

Solder the resistors just like you did with the first one.
Clip all the leads.

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



Flip over the PCB and check that all the legs for the buttons are sticking out.

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!

Flip over the PCB and solder in the three legs of the potentiometer

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

Flip over the PCB and solder in the 28 pins of the port expander.
Next we will attach the header, there is a standard 'extra tall' header included in the kit. However, if you want to attach a cobbler or GertBoard, etc to the plate, you may want to opt for one of our stacking headers, they're extra long so you can plug in an IDC cable on top!
Before we solder in the header, remove the bumper from the backing and attach it on the underneath so its right over the Ethernet jack when the PCB is plugged in.

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
Place the 2x13 header onto your Pi, and slide the plate on top, it should fit perfectly.

Now we will solder all 26 pins for the plate - this will send power and data between the two boards and also provide a mechanical stability. You may need to hold the plate down with tape to get it sitting flat against the Pi.

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

Finally, we place the LCD.
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
Slide the LCD over the header so that it is perfectly centered over the four holes and the silkscreen.

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!
Flip over the assembly, carefully. Then solder in the 16 or 18 pins of header
WARNING: If you're using the new Raspberry Pi model B+ with 4 USB ports you will need to take some extra steps to ensure the backlight resistor leads do not touch the USB ports and short out. See the steps below for more details.

Model B+ Protection

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.

There is current limiting in the resistor circuit so it shouldn't damage the Pi if there is a short, but to be sure it is advised to cover the USB port and resistor leads in a few layers of electrical tape. Be sure to cut the resistor leads as short as possible with flush cutters and try to ensure there are no sharp edges from the cut leads or solder. See the photo below with arrows pointing to the two locations you should place electrical tape.

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.
That's it! You're done soldering, now you just have to run the code in the Usage section next.

Last updated on 2016-03-04 at 03.43.42 PM Published on 2012-11-21 at 02.51.59 PM